Insights

From RSV to hMPV: Building the Next Generation of Respiratory Challenge Models

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:40:01 GMT

Respiratory viruses don’t wait for clinical trial calendars. Their seasonality, strain variability, and unpredictable circulation patterns have long frustrated vaccine developers and trial designers. But infection can be simulated — safely, reproducibly, and on demand. That is the promise of human challenge models. And as the field evolves, so do the pathogens we need to understand. Respiratory syncytial virus (RSV) was once the frontier. Now, human metapneumovirus (hMPV) is stepping into the spotlight.

The Rise of hMPV

hMPV has quietly circulated for decades, but only recently emerged as a global concern. With rising case numbers and no approved vaccine or antiviral, it has become a priority for respiratory researchers. Like RSV, hMPV is difficult to study in the field — often co-circulating with other viruses and evading seasonal surveillance. Earlier this year, outbreaks in China and India triggered pandemic concern from the media, which isn’t possible for this virus as pandemics are from viruses that newly enter the human population from animals. This is the not the case for hMPV but it is nonetheless an important pathogen that causes significant epidemics every winter season.

Human metapneumovirus is elusive, which is why it wasn’t formally identified until 2001 — not because it was new, but because it was so difficult to detect. hMPV was discovered through persistent tissue culture work, where cytopathic effects took up to 17 days to appear — well beyond the standard discard window in most labs. Retrospective serology later revealed antibodies in samples dating back to the 1950s.

Thus, hMPV is not new in the scientific community. It has been known for two decades by the scientific community. However, what is new is the mainstream awareness, and the recognition that it targets the same vulnerable populations as RSV: infants, the elderly, and those with underlying conditions. This history underscores the challenge: hMPV is hard to detect, hard to isolate, and hard to study in the wild. Which is exactly why a controlled, reproducible challenge model is so valuable.

RSV as a Blueprint

RSV challenge models were a turning point. They demonstrated that symptomatic infection could be recreated in healthy volunteers, enabling early efficacy data and informing later-stage trial design — all within a controlled clinical setting.

The success of RSV was not just about the virus. It was about the infrastructure behind it:

The ability to characterise strains in the lab
The precision of endpoint selection
The reproducibility of infectivity across cohorts

RSV vaccines had failed for decades, sometimes making disease worse. Then the discovery was made on exactly how to design vaccines to produce effective virus neutralising antibodies that solved the problem, the so named preF vaccines, named after the viral protein they target. Vaccine efficacy studies using the RSV challenge models were the first proof of concept that vaccination against RSV could be safe and effective. That data de-risked the field and gave companies confidence to move forward. These elements formed the blueprint for what came next — the development of the hMPV challenge model.

Building the hMPV Challenge Model

Developing a challenge model for hMPV required more than clinical ambition. It demanded deep lab expertise:

Characterising the strain for safety and infectivity
Validating symptomatic disease in healthy volunteers
Ensuring reproducibility across endpoints and assays

Clinical isolates were sourced from patients who can become infected in the community naturally, some of which were from paediatric patients hospitalised with severe hMPV infection. These samples were triaged for safety, growth potential, and absence of co-infectious agents. The selected isolate was manufactured under GMP conditions with minimal passage, preserving its natural characteristics and minimizing cell adaptation. The final product is a medical-grade virus, frozen in calibrated dilutions and ready for direct human inoculation — no post-GMP manipulation required.

These models are made safe not by weakening the virus, but by careful volunteer selection and rigorous monitoring. That approach allows real infection dynamics to be studied with wildtype viruses while protecting participants.

Safety and Endpoint Design

Volunteers are monitored daily for symptoms, viral load, and patient perception. Symptom severity is scored categorically (0–3), and nasal discharge is measured using pre-weighed tissues — a crude but effective metric. The key endpoint is moderate-to-severe symptomatic infection (grade 2+), which aligns closely with field trial recruitment triggers.

Endpoints must translate. If a volunteer perceives they have a cold and it is bothersome enough to stop daily activities, that is exactly the kind of trigger that determines recruitment in a field trial. Challenge models must mirror that reality, hence careful design of the trial endpoints to ensure that goal is realised.

Immunological Insights and Model Flexibility

Unlike previous models, this hMPV study did not pre-exclude volunteers based on antibody levels. Despite this, the model produced high infection rates and robust disease curves. A clear correlation was observed between baseline antibody levels and disease severity — allowing future studies to either stratify or pre-select volunteers depending on the trial’s goals.

This gives two options. If efficiency is the priority, volunteers can be pre-screened to maximize moderate-to-severe infections with fewer participants. If real-world translation is the goal, all comers can be included and stratified. The model works both ways.

Benchmarking Against RSV

The hMPV model was benchmarked against the extensively validated RSV-A model. Disease severity, duration, and symptom profiles were comparable, with hMPV peaking slightly earlier. This similarity reinforces the model’s reliability and its potential to support vaccine development across the pneumovirus family, just as the RSV-A model has already been used so successfully in the development of the current RSV Vaccines

The Future of Respiratory Modelling

As new pathogens emerge and old ones evolve, the need for agile, lab-enabled challenge models will only grow. RSV showed what is possible. hMPV is showing what comes next.

The future is not about chasing viruses across seasons. It is about designing disease — safely, ethically, and with scientific precision. That is how vaccines and antivirals for the pathogens that matter most will be accelerated.

Learn more about the hMPV challenge model and its clinical data - register for access to this on demand presentation.

Controlled Human Infection Model's (CHIM) in your backpack: how Human Challenge Trials support regulatory approval of travel vaccines

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:40:00 GMT

Helping to protect travellers

A ‘travellers vaccine’ is a vaccine administered to travellers from a ‘non-endemic region’, before they visit an endemic region, and they form an important component of travel medicine. Beyond protection of tourists, they are also administered to prevent the importation of vaccine-preventable diseases ‘at home’. Proof of immunization for travel dates back to the first smallpox vaccine in 1796. It took another century to develop the next generation of vaccines against cholera, rabies, and typhoid fever. During the 20th century, the range of vaccines used by travellers largely expanded with yellow fever, poliomyelitis, tetravalent meningococcal, and hepatitis A vaccines. The International Certificate of Inoculation and Vaccination was implemented in 1933. 1

Currently, vaccines are administered to travellers following a risk assessment based on their destination and individual risk factors, but certain countries also mandate certain vaccines.

Most of the time, vaccines administered to travellers have been developed for use in endemic regions. In a number of cases, vaccines have been specifically developed to serve the travellers market. This blog presents a case study of how Human Challenge Trials can help support the regulatory development of this type of vaccine.

Cholera - Overview

Cholera is a severe, rapidly-dehydrating diarrheal disease caused by toxigenic serogroups of the bacterium Vibrio cholerae. It constituted the greatest epidemic disease of the 19th century.

Cholera is endemic in areas of Africa, the Indian sub-and Southeast Asia, where it remains a disease associated with poverty and poor sanitation, Recently cholera cases have been reported in the Caribbean (Haiti and Dominican Republic). In developed countries, cholera is extremely rare, and cases are traced to travellers returning from endemic areas. 2

Vaccine Development

Developing a cholera vaccine for travellers using a Controlled Human Infection Model
Vaxchora is a live oral cholera vaccine intended to prevent cholera disease in adults and children aged from 6 years (18 years in the US).

The vaccine is specifically aimed at those travelling to cholera-endemic regions. It contains a weakened form of the cholera bacterium Vibrio cholerae (serogroup O1). Vaxchora received marketing authorisation valid throughout the EU in April 2020 and was approved by the FDA in June 2016. 3,4

Developing a vaccine for cholera – in particular one aimed at travellers – has a major challenge as performing a Phase III field trial in this population would be difficult, as both the placebo and the active group would need to be meaningfully exposed to cholera – in the same order of magnitude – in order to achieve a conclusive result on efficacy. To be able to demonstrate efficacy, a Controlled Human Infection Model (CHIM) trial was included in the development pathway as the pivotal efficacy study, replacing a Phase III efficacy field trial. In this CHIM study, 197 healthy adults aged 18 to 45 years received a single dose of either Vaxchora (95 volunteers) or placebo (102 volunteers) and were then given infectious cholera bacteria (O1 strain).

Results

The CHIM trial showed that Vaxchora can prevent symptoms of cholera in people coming into contact with the bacteria and provided the pivotal part of the efficacy data. In order to have a sufficiently large safety database, a main safety immunogenicity study involving 3,022 healthy adults aged 18 to 45 years was performed. Two further studies in special populations confirmed that giving Vaxchora to adults aged 46 to 64 years or to children and adolescents aged 6 to 18 years was effective at producing antibodies against cholera bacteria.

Conclusion

Human challenge trials not only play a role in supporting the development of vaccines by serving as a proof-of-concept trial, but as the above example illustrates, can in some very specific cases, also be used as a more pivotal element of the development.

References

Pavli A, Maltezou HC. Travel vaccines throughout history. Travel Med Infect Dis. 2022 Mar-Apr;46:102278..
Gabutti G., Rossanese A., Tomasi A., Giuffrida S., Nicosia V., Barriga J., et al. Cholera, the current status of cholera vaccines and recommendations for travellers. Vaccines. 2020;8:606.
Vaxchora: EPAR EMA/82271/2020 Committee for Medicinal Products for Human Use (CHMP) assessment report. Vaxchora International non-proprietary name: cholera vaccine, oral, live Procedure No. EMEA/ H/C/003876/0000
FDA. Vaxchora information

Unravelling the hMPV Surge: From Media Attention to Vaccine Development

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:40:00 GMT

Inflammatory messaging

It’s a confusing picture out there on what is really going on with hMPV infections globally currently. Since early January hMPV (or human metapneumovirus if we are to use its’ full name) has been in our news feed nearly daily following reports from a significant surge of infections in China. In recent days, China has reported that the rate of new hMPV infections in their county is now declining. However, the reports from China have led to a flood of articles across the news outlets, some with quite inflammatory headlines and others with a more balanced approach. Taken out of context, reports that cases have doubled within a week in the USA can sound alarming, but this is a virus known to circulate in winter and spring so such patterns are not unusual and within what we would expect for this and other seasonal respiratory viruses.

Fear of the unknown

Among my fellow virologists, hMPV was of course well known as an important respiratory pathogen before it became headline news earlier this month. Despite the COVID pandemic creating many “armchair virologists”, I think it’s fair to say, that, prior to January, hMPV was not a household name. In fact, much of the general public had never heard of hMPV. Pictures of overwhelmed hospitals from virus infections naturally bring back recent memories from the onset of the COVID pandemic so this, coupled with the virus name being unfamiliar, explains the understandable concern raised.

Welcome clarification

It was great to see the highly respected and trusted WHO stepping in to clarify exactly what they understood to be the picture in China and that “surge” of hMPV infections was in fact within normal expected levels for this time of year. During Dr Harris’ statement, she was keen to point out that actually most new respiratory infections in China were still being caused by seasonal influenza and not hMPV, reminding us that flu remains the more significant burden and highest impact on struggling health systems with the levels of hospitalisations caused.

Greater public awareness helps drive research

Nonetheless, hMPV is an important pathogen so I welcome the fact that this virus has been brought to the attention of the world’s media this month. Greater awareness of the viruses that continue to cause significant human disease and suffering is surely a good thing; raised awareness typically leads to greater research funding and ultimately improved medical countermeasures. Whilst hMPV is already well known within the scientific community, it is not nearly as well studied as influenza and RSV (Respiratory Syncytial Virus), either at an academic level or by industry in developing vaccines and treatments. This is perhaps not surprising given that hMPV was not discovered until 2001, so far more recently than RSV or influenza which we have known about for much longer. Furthermore, it was long considered extremely difficult to produce effective vaccines against the Pneumoviridae - the virus family for which both RSV and hMPV are members. This started to change with the discovery of the importance of the pre-fusion formation of RSV’s F protein as the appropriate vaccine target. Vaccines designed to elicit antibodies specifically targeted against the pre-fusion formation of virus’ F protein, known as the pre-F vaccines, have totally changed the paradigm and demonstrated that effective vaccines are possible.

Challenge studies derisk vaccine development

Developing a vaccine based on any completely new construct or scientific approach always carries risks, particularly regarding the ability to achieve the desired protective effect. Human viral challenge models have long been considered an ideal way to mitigate the risk of an expensive large-scale vaccine trial failure. This is because they involve the direct inoculation of healthy study participants with the virus of interest, which, therefore, allows for direct testing of vaccine efficacy in a highly controlled setting and requires far fewer study participants than conventional trials to determine vaccine efficacy. hVIVO is very proud of its significant role in bringing the world’s first efficacious RSV vaccines to market via the use of their RSV challenge model. The model provided the first-ever demonstration of vaccine efficacy in humans for the RSV pre-F vaccines. This breakthrough led to multiple RSV pre-F vaccines being tested in the model and the successful proof-of-concept results from these challenge studies were pivotal in fast-tracking the RSV vaccines to market.

RSV vaccine success drives hMPV vaccine development

I was delighted to have observed a couple of years ago that the RSV vaccine success led some of those biotech and pharma RSV research teams to turn their attention to hMPV. Consequently, there are now a number of promising hMPV vaccines in the development pipeline. Albeit most have not yet reached the development stage of efficacy testing in humans and none have yet demonstrated efficacy to prevent or significantly reduce the hMPV disease burden.

High hopes for the hMPV challenge model

Following this trend of RSV vaccine research teams to convert to working on hMPV, over the past year or so, hVIVO have utilised their challenge model development expertise to develop an hMPV challenge model, which culminated in a pilot challenge study late last year. As reported earlier last week, the pilot study was highly successful in demonstrating that an effective hMPV challenge model could be established with good infection rates observed and, as expected, in a safe and controlled manner. There are high hopes that the hMPV challenge model can help fast-track the development of hMPV vaccines, just as the RSV model did for RSV vaccines, to ultimately gain some control over this important global pathogen and save lives.

Why are Biotech’s & Pharma Using Human Challenge Studies for Drug Development?

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:39:59 GMT

What is a human challenge study?

In a human challenge study, healthy volunteers are intentionally infected with a virus/bacteria or parasite in a quarantine facility. The volunteers are monitored under 24/7 supervision by medical experts. These trials are strictly regulated and approved by the applicable regulators and ethics committee. These studies are performed to help further scientific research and drug development.

Human challenge studies allow for data collection in a controlled environment, this data gives further insights to see if a vaccine or antiviral is effective and contributes to a deeper understanding of how an infectious disease affects a group of volunteers in a controlled medical environment.

How are vaccines and therapeutics developed?

Human challenge models are featured in phase II stages of clinical research, but in a number of specific cases can be used as a pivotal trial.

What is the difference between a Field Trial and a Human Challenge Trial?

Why do Healthcare providers such as Biotechs & Pharma use Human Challenge Studies?

Human challenge studies can be an important factor for healthcare providers, such as biotech's and pharma as they generate valuable data in dosing, safety and efficacy data. They also can be performed in a short time-frame (by comparison of the drug development journey – getting from idea to market) and be used as a supportive measure to prove the effectiveness of the challenged drug or antiviral.

It is important to note that human challenge studies are widely accepted by global regulators, and are of great interest to the healthcare industry, due to their validity and their ability to provide further scientific understanding.

How can the hVIVO Group help with a Drug Development plan?

As the hVIVO Group compromises of two companies, hVIVO & subsidiary Venn Life Sciences, the organization offers a full-service solution.

Venn Life Sciences is an integrated drug development consultancy, which offers CMC (chemistry, manufacturing and controls), preclinical, Phase I & II clinical trials design and execution. Together the companies offer a full-service solution, from consultancy and drug development, to running the human challenge model.

hVIVO, the world leader in testing infectious and respiratory disease vaccines and therapeutics using human challenge clinical trials. The Group provides end-to-end early clinical development services to its large, established and growing repeat client base, which includes four of the top 10 largest global biopharma companies.

The Group includes:

Unique portfolio of 11+ human challenge models to test a broad range of infectious and respiratory disease products
World class challenge agent manufacturing
Specialist drug development and clinical consultancy services via its Venn Life Sciences brand,
Laboratory Services offering through the hLAB brand, which includes virology, immunology biomarker and molecular testing.
The Group offers additional clinical field trial services such as patient recruitment and clinical trial site services.

hVIVO runs challenge studies in London from the Whitechapel quarantine clinic, a state-of-the-art QMB clinic with its highly specialised on-site virology and immunology laboratory, and a lab in Plumbers Row. To recruit volunteers/patients for its studies, the Company leverages its unique clinical trial recruitment capacity via its FluCamp volunteer screening facilities in London (Plumbers Row) and Manchester.

Building on decades of unrivalled experience, hVIVO provides world class expertise and capabilities in challenge agent manufacture, a unique portfolio of established human challenge models to test a broad range of infectious and respiratory disease products, and specialist drug development and clinical consultancy services.

To learn more about the advantages of a Human Challenge Trial, read our blog here.

Tripledemic Takedown: How Human Challenge Trials are Ideal to Expedite Multivalent Vaccine Development

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:39:58 GMT

Introduction

The recent rise of the "tripledemic" – the concurrent spread of the influenza virus, SARS-CoV-2 virus, and respiratory syncytial virus (RSV) – is posing significant risks, especially to older adults and those with chronic conditions or compromised immune systems.[1] Although flu and RSV have shown strong seasonal patterns, peaking in the winter months, the convergence of these viruses with COVID-19 exacerbates healthcare pressures during the winter, adding significant strain to hospital resources. The overlap in symptoms of these viruses – including fever, cough, runny or stuffy nose, and sore throat – makes it difficult for healthcare professionals to identify the specific virus from symptoms alone with distinguishing diagnostic tests required to facilitate exact diagnosis and inform treatment strategies.

The availability of Human Challenge Trials (HCT) represents a significant leap forward in our list of tools to help tackle these diseases. This blog explores how such trials can fast-track the development of multivalent vaccines, designed to protect against multiple viruses at the same time. The need for such vaccines has never been more urgent.

Moving Towards a Multivalent Vaccine

Currently, vaccines for flu, RSV and COVID-19 are formulated independently and administered separately. The tripledemic poses a unique challenge, and so a combination vaccine, which can protect against all three or even multiple viruses, is an ideal solution. Multivalent vaccines offer several benefits:

Increased Vaccination Uptake: Simplifying the vaccination process into a single shot can lead to higher uptake.
Reduced Healthcare Burden: Administering one vaccine instead of three reduces logistical challenges and the strain on healthcare systems.
Cost Efficiency: There is a potential for cost savings in production and administration.

Developing these vaccines through traditional methods, however, is time-consuming and complicated in terms of regulatory approval and formulation to ensure each vaccine component still remains effective and safe once combined. Regulators typically require evidence of at least safety and immunogenicity of the combined vaccine, and potentially also efficacy, even if these parameters have been established for the individual vaccines.

The Role of Human Challenge Trials

Human challenge trials (HCT), sometimes also referred to as Controlled Human Infection Studies, streamline this process by allowing simultaneous testing of multiple antigens and play a crucial role in vaccine development, especially for new technologies like mRNA vaccines. Unlike traditional field trials, which rely on participants naturally encountering a virus, HCT take a more controlled approach – experimentally inoculating the trial subjects with a specific medical grade version of the virus (the challenge virus). Separately inoculating difference participants on the trial with a different target virus ensure efficacy data is collected against all pathogen targets and facilitates efficient multivalent vaccine development.

Advantages of HCT include:

Precision: By deliberately exposing participants to a specific strain of the virus, there is a greater level of control – not possible in traditional field studies – and elimination of the variability seen in community-based infections. Often not all of the viruses wanting to be tested are circulating at high enough levels during the trial duration to collect sufficient data on the efficacy of all components of the combination vaccine; this issue is totally eliminated in HCT.
Speed of Data Generation: In traditional field trials, subjects are vaccinated and then asked to continue with their normal life, leaving it to random chance that they will be exposed to the virus of interest naturally in the community. Consequently, the majority of subjects are not exposed to the virus, so it is not possible to make any assessment of vaccine efficacy from those subjects. As all subjects in HCT are directly exposed to the virus, they all contribute to vaccine efficacy assessments and substantially less subjects are needed; these HCT are completed much faster than traditional field trials.
Efficiency: With statistically significant data obtained, with the help of Data Management services such as those provided by Venn Life Sciences from fewer participants than field trials, HCT are more resource-efficient and have reduced logistical and financial burdens. Furthermore, unlike field trials that often need to extend the study duration at increased cost due to one or more of the viruses of interest not circulating to high enough levels during the season the trial was run, HCT have far more predictable controlled budgets and timelines as they are not dependent on level of community circulating virus and can be conducted all year round.

HCT can also be used to complement field studies by supplying additional data for a specific pathogen in a combination vaccine that was in low circulation during the field trial, so the efficacy data is effectively supplemented by HCT data.

Whilst HCT are often run in healthy adults with no risk factors for severe illness such that they are expected to clear the infection without invention by their own immune response, HCT can also be against pathogens where an individual’s existing immunity is not expected to be sufficient to clear an infection. In such incidences, proven treatments would need to be available. Malaria is an example of this as the strain of the parasite can be carefully controlled and chosen for a HCT, to ensure that it is sensitive to antimalarial drugs and not resistant so that we can treat the subject in the HCT to prevent the development of malarial disease symptoms.

Recent Advancements

Human challenge trials are revolutionising the approach to vaccine development by offering a faster, more precise, and efficient approach to studying vaccine efficacy. As the global leader in Human Challenge Trials, in 2021, hVIVO performed the World’s first COVID-19 HCT, set up during the height of the pandemic to provide a tool to quickly test a range of different vaccines to ascertain the best one to use should the first generation of vaccines had not proven to be successful. This model has now progressed with the development of later variants of the SARS-CoV-2 virus, such as Omicron BA 5.

Another ground-breaking example is studies at hVIVO that have provided efficacy data, which had a massively positive impact in bringing RSV vaccines to market in the last few years despite there being no vaccine available since RSV was isolated in 1956. Every year in the US, the CDC estimates RSV causes 60,000 to 80,000 hospitalisations and 100–300 deaths in children under 5 years and up to 160 000 hospitalisations and 6000–10,000 deaths in adults over 65 years.[2] HCT, conducted at hVIVO, first demonstrated the efficacy of a novel RSV vaccine, which gave confidence to the market that RSV vaccination may be possible. This led to several pharmaceutical companies expediting their RSV vaccine programmes by testing their efficacy in a HCT at hVIVO and obtaining fast-track and breakthrough status with the regulators, which facilitated subsequent clinical development steps. Consequently, the quality data from the HCT gave both the vaccine producers and the regulators confidence that the vaccine can work and provide an effective solution for this unmet medical need.[3]

Conclusion

With RSV vaccines now on the market, thanks to human challenge trials conducted at hVIVO, there is greater potential to address the challenges posed by the tripledemic, by integrating such studies to significantly shorten the timeline in developing and bringing multivalent vaccines to market. While this remains a long-term objective, the development of combination vaccines, through such trials underline its ethical and practical value. Not only will this be a cornerstone to managing several respiratory viruses at the same time, but also has the potential to save thousands of lives and alleviate the burden on worldwide healthcare systems, particularly if the higher vaccine update expectations of a combination vaccine are realised.

References

GSK Behind the science magazine article The ‘tripledemic’ will hit older people hard this winter - but we can reduce the impact (accessed 20 June 2024)
Respiratory syncytial virus vaccines: the future is bright. Lancet Respir. Med. DOI: https://doi.org/10.1016/S2213-2600(24)00184-X
Morningstar news article IN THE KNOW: hVIVO involvement in drug approval should boost interest (accessed 20 June 2024)

Empowering Next‑Gen Infectious Disease & Vaccine Development

marketing@hvivo.com (Elisa Masat) — Fri, 10 Apr 2026 18:39:57 GMT

Essential tools and technology to aid research

Infectious disease research is evolving faster than ever, driven by the need for more sensitive, scalable, and precise molecular tools. As pharma and biotech organizations push to accelerate vaccine development, improve early‑stage decision‑making, and enhance clinical trial success rates, the ability to extract more insight from limited biological samples has become essential.

Today’s clinical trial laboratories, especially those supporting virology, vaccine development, and early‑phase drug discovery, require technologies that deliver high‑resolution data with minimal sample usage. This is where the next generation of digital PCR (ddPCR) platforms is transforming the landscape.

Sponsor Challenges: More Insight from Less Biological Material

Clinical studies typically produce a limited number of high‑value samples, particularly in early‑phase infectious disease and vaccine research. Laboratories must maximise data output, detect low‑frequency mutations, support precise quantification, and maintain accuracy across high‑throughput clinical trial settings.

Solution: The QX700S Digital PCR Platform (ddPCR)

The Bio‑Rad QX700S ddPCR platform delivers a powerful leap forward in molecular diagnostics, infectious disease research, and pharma‑grade assay development. It offers high sensitivity, 7‑color multiplexing enabling up to 21 targets, ultra‑low sample volume requirements, and high‑throughput automation.

Impact on Clinical Trials and Research

ddPCR strengthens its role as a core component of modern molecular biology strategies in drug development. When paired with Next Generation Sequencing (NGS), digital PCR enhances detection sensitivity and supports comprehensive analytical frameworks for infectious disease studies, vaccine efficacy monitoring, viral mutation analysis, and gene therapy characterization.

Key Benefits:
• More insights from every sample
• Unmatched sensitivity for mutation verification
• Rapid turnaround times
• Reproducible, high‑quality data
• Future‑ready molecular workflows

Empowering Next‑Gen Infectious Disease & Vaccine Development

hVIVO becomes the first global clinical trial laboratory to adopt the Bio-Rad QX700S platform, reinforcing our commitment to infectious and immunology disease research and clinical trials.

Learn more about our laboratory services.

Human Challenge Studies: Their Conduct and Safety Aspects

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:39:57 GMT

If 100 clinical research professionals either from the CRO or Pharma/Biotech industries were surveyed and asked to explain what a human challenge study is, the most common answer most probably would be – “I have never heard of it” and very few of them would give the correct description. This is not something extraordinary, as this type of clinical studies is unique and niche, and highly therapeutically focused. A different situation in responses would be if the respondents of such survey would be those working in the field of infectious diseases or early clinical development of vaccines.

Even though human challenge studies or controlled human infection model (CHIM) studies may sound like something new within the clinical research space, over the past 80 years they have been conducted for over 20 different infectious disease pathogens and over 45,000 volunteers have participated in these clinical trials (1,2). Over 200 CHIM studies have been registered on clinicaltrials.gov. The numbers will definitely increase in the years to come, especially due to significantly increased interest in vaccine and antiviral development after the COVID-19 pandemic (3). This article overviews human challenge studies, specific aspects of their conduct and safety for the healthy volunteers participating in CHIM studies.

What is a Human Challenge Study?

Human challenge studies or CHIM studies is a specific type of clinical trials, which involve the intentional infection of a healthy, adult, consenting volunteers with an infectious agent (3). In other words, healthy volunteers enrolled in these studies are infected on purpose with a particular pathogen, in order to investigate the efficacy of vaccines, antivirals, anti-infectives or anti-parasitic drugs.

Even though infecting a healthy person on purpose might sound very unethical or even dangerous, these studies are conducted in a highly controlled environment. Moreover, there is a proven track record of safety of these clinical trials discussed hereinafter in this article.

Conduct of Human Challenge Studies

Even though human challenge studies may sound as very complex and complicated, from their set-up and management perspective many elements are very similar or even the same as for any other clinical trial. On the other hand, pathogen inoculation and disease control require specific experience and environment, therefore, these studies are mostly conducted in specialized units.

From a regulatory perspective, CHIM studies are considered to be either Phase Ib, Phase I/II or Phase IIa clinical trials, therefore, the same study start-up timelines apply. Usually, first in human data have to be obtained prior to the conduct of human challenge study. The flow of a human challenge study is shown in Figure 1. Some specific aspects of healthy volunteer screening and consent, randomization and treatment, as well as monitoring and follow-up are discussed further.

Healthy Volunteer Screening and Informed Consent

Controlled human infection model studies, as any other healthy volunteer clinical trials starts with healthy volunteer screening. Depending on the pathogen used in a challenge study, many healthy volunteers are not serologically suitable to participate in the study, due to the high immunity against the pathogen and therefore, low probability to get infected. This means that the number of subjects screened for a challenge study might be much higher in comparison to the usual healthy volunteer clinical trial.

The ethical aspects of CHIM clinical trials have been widely debated, with specific focus on the informed consent process and the understanding of risks and benefit (4,5). In order to be included in a challenge study, healthy volunteers are thoroughly screened based on inclusion and exclusion criteria and enrolled after an informed consent process. Informed consent form is usually quite extensive, as it must include not only the information related to investigational medicinal product, but also to the pathogen inoculation and associated risks of the infection. Therefore, informed consent process may frequently include a test of understanding (3).

Randomization and Treatment

The selected study participants are randomized to receive either the investigational medicinal product (IMP), comparator (if applicable) or placebo, and at a certain timepoint challenged with the infective pathogen. Worth mentioning that not all study participants may get infected with the disease after the pathogen has been inoculated, some may experience asymptomatic disease.

Based on the type of IMP (vaccine, therapeutic or prophylaxis), timing of the dosing and challenge pathogen inoculation may differ. While vaccines are usually administered 1 or 2 months prior to the challenge, prophylactic or therapeutic treatments may be administered just before or after pathogen inoculation, based on the treatment regimen and the onset of disease. Depending on the pathogen, participants may be treated with rescue medication at a defined time based on the study protocol and development or severity of symptoms.

Monitoring and Follow-up

Challenge studies requires careful monitoring throughout the clinical trial period, vital signs, and other clinical and laboratory parameters are monitored. Patient diary cards are often used to track symptoms, which in many cases are an important endpoint.

Depending on the disease model used in a human challenge clinical trial, study participants have to stay in the quarantine after pathogen inoculation for a certain period of time. Such period may vary from couple of days to weeks, as described in a clinical study protocol. This is required not only for the clinical trial data collection purposes, but also to ensure health and safety of the subject, public safety and infection control. Follow-up visits depends on the study protocol but usually the follow-up period is quite short (1-2 months post discharge).

Safety of Healthy Volunteers

As in all clinical trials – safety of study participants is of most importance. So, is it safe to infect healthy volunteer with a certain pathogen in order to test a new vaccine or antiviral? Challenge studies are designed to limit and minimize risks to participants and are done with strict infection control measures to limit and reduce third-party risks (6). The dose of pathogen to be inoculated is carefully selected, the timing of inoculation is defined in a clinical study protocol. Therefore, with all risk management measures applied, CHIM studies have an excellent safety record.

For example, in the last 30 years of work by the Walter Reed Army Institute of Research conducting CHIM Malaria studies, not one person has been hospitalized due to adverse events related to the study (3). Similarly, in the last 20 years of work by a specialized commercial human challenge study site hVIVO, with over 60 challenge studies conducted and over 3000 healthy volunteers enrolled, these studies have demonstrated an excellent safety profile.

To sum up, human challenge studies has been conducted for many years and provide highly valuable data in clinical development programs. Therefore, such data collected during CHIM studies play an important role in early development of vaccines and anti-infectives. Due to their specifics, challenge studies are conducted only at a limited number of academic centres and a few commercial enterprises, like hVIVO. All such studies require specific clinical research infrastructure, well trained scientists and clinicians, protocols with well-defined inclusion and exclusion criteria, rigorous informed consent processes and careful monitoring and governance (3).

References

J.A. Kalil, S.A. Halperin, J.M. Langley, Human challenge studies: a review of adequacy of reporting methods and results, Future Microbiol. 7 (4) (2012) 481–495.
M. Roestenberg, M.A. Hoogerwerf, D.M. Ferreira, B. Mordmüller, M. Yazdanbakhsh, Experimental infection of human volunteers, Lancet Infect. Dis. 18 (10) (2018) e312–e322.
Sekhar A, et al. Human challenge trials in vaccine development. Semin Immunol. 2020. PMID: 33262068
B. Bambery, M. Selgelid, C. Weijer, J. Savulescu, A.J. Pollard, Ethical criteria for human challenge studies in infectious diseases, Public Health Ethics 9 (1) (2016) 92–103.
T. Hope, J. McMillan, Challenge studies of human volunteers: ethical issues, J. Med. Ethics 30 (1) (2004) 110–116.
Jamrozik E, Selgelid MJ. COVID-19 human challenge studies: ethical issues. Lancet Infect Dis. 2020 Aug;20(8):e198-e203. doi: 10.1016/S1473-3099(20)30438-2. Epub 2020 May 29.

Human Challenge Trials as a tool in raising funding

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:39:56 GMT

Introducing challenge trials

In human challenge studies (HCT) or Controlled Human Infection Models (CHIM), healthy volunteers are administered a pathogenic or virulent strain of a challenge agent, which can be a virus (ie influenza), bacteria (ie cholera) or a parasite (ie malaria).

In a historical context, the concept of challenge studies is not new. The experiments conducted by Louis Pasteur in the 19th century, where chickens were challenged with a weakened bacteria causing chicken cholera and immunized from further chicken cholera infection, can be seen as a type of challenge study. Human Challenge Trials have been performed in the United Kingdom since 1946 when the Medical Research Council established the Common Cold Unit (CCU) (also known as the Common Cold Research Unit [CCRU]) at Salisbury, Wiltshire. The aim was to undertake laboratory and epidemiological research on common colds in view of reducing human and economic costs.

Use of Human Challenge Trials

Human challenge trials are usually performed after phase 1 safety trials and are usually classified as phase 2 trials

In current drug / vaccine development human challenge trials can be used in a variety of ways, like dose-finding study, in preparation of field trials, but the most common use is that HCT are used as phase 2 proof-of-concept (PoC) studies.

These Human Challenge proof-of-concept trials designed to provide early evidence about efficacy and if a drug is likely to be successful in later clinical trial phases, and this is a short timeframe. Hence, PoC studies can guide drug developers to make smarter "go or no-go" decisions about if proceeding with larger, more expensive studies in the next stage of drug development. The results of PoC studies are critically pivotal for strategic decisions in early drug clinical trial development.

Human Challenge Trials have also previously been accepted as `preliminary clinical evidence` in the framework of Fast Track designation by the US Food and Drug Administration.

Due the reduced number of subjects needed for a Human challenge trials (40-60 subjects) compared to a classic `field` PoC trial (180-600 subjects), Human Challenge Trials forms a cheaper alternative. In addition their shorter duration allows for a quicker availability of efficacy data.

Use of Human Challenge Trials in raising funding

With their reduced cost and shorter duration, phase 2 Human Challenge Proof of Concept trials are a very helpful tool in supporting your company in raising funds - be it an additional fundings round with private investors or initial clinical data used as basis for an Initial Public Offering (IPO).

In summary, the core attributes of a Human Challenge Trial compared to a traditional field trial are:

Reduced cost
Reduced timeliness
Early efficacy data
`Clean data` without the background noise of Field Trials

UK Life Sciences Sector Plan 2025: What it Means for the Future of Clinical Research

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:39:55 GMT

What is the UK Life Sciences Sector Plan?

This national strategy is designed to strengthen the UK’s position in health and biomedical innovation. It aligns government, industry, and research efforts to accelerate the development and delivery of new healthcare technologies and treatments.

The plan, launched in July 2025, provides an overview of the 10-year mission for the UK of becoming Europe's leading life sciences economy by 2030 and establish the UK as the world's third most important life sciences economy - behind the US and China - by 2035.

According to the UK Government, The life sciences sector already plays a vital role in the national economy, employing over 304,000 people across nearly 7,000 businesses and generating more than £108 billion in turnover in 2021/22. This strong foundation underpins the ambition of the new sector plan.

The plan is supported by government funding of over £2 billion, alongside funding from UK Research and Innovation (UKRI) and the National Institute for Health and Care Research (NIHR). The strategy is developed in consultation with industry, engaging with over 250 organisations and 400 individuals across life sciences businesses, providers, and patient charities.

This is a new model of partnership between science and society, between government and industry, and between economic and health policy. Better health and stronger growth go hand in hand, and the most effective healthcare relies on the rapid adoption of new technologies and treatment.

The Action Plan: Driving Innovation and Growth

The plan is built around three strategic pillars:

Enabling world-class research and development (R&D) – to take advantage of, and build upon, the UK’s historic scientific strengths by investing in translational models and networks, commercial clinical research, and our data and genomics capabilities. This includes support for preclinical model research networks and targeted funding for biotech and medtech small and medium-sized enterprises.
Making the UK an outstanding place in which to start, grow, scale, and invest – to ensure that brilliant ideas are built and scaled into multi-billion-pound companies in the UK, our manufacturing sector is supported to thrive, and that we drive Foreign Direct Investment (FDI).
Driving health innovation and National Health Service (NHS) reform – ensuring patients get rapid access to the most clinically and cost-effective new technologies, and enabling the shifts from sickness to prevention, hospital to community, and analogue to digital.

With life sciences accounting for around 17% of all UK business R&D expenditure, the sector is central to the UK’s innovation landscape and economic competitiveness. To drive early impact, the government will initially focus on six headline actions:

Health Data Research Service (HDRS) – A £600 million investment will create a secure, AI-ready health data platform integrating genomic, diagnostic, and clinical data to attract global trials and research.
Faster clinical trials – Building on the O’Shaughnessy reforms, the UK will reduce trial setup times to under 150 days and aims to double commercial trial participation by 2026 and again by 2029.
Manufacturing investment – Up to £520 million will be deployed through the Life Sciences Innovative Manufacturing Fund (LSIMF) to enhance sovereign capability, strengthen domestic health resilience and supply chain security.
Streamlined regulation and market access – The Medicines and Healthcare products Regulatory Agency (MHRA) will become more agile, with international reliance models and better alignment with the National Institute for Health and care Excellence (NICE) to speed up access to medicines and medical devices.
Simplified NHS procurement – A new Rules-Based Pathway and NHS Innovator Passport will make it easier for innovative products to be adopted across the health system.
Strategic industry partnerships – The government will secure at least one major partnership annually with leading life sciences companies and provide dedicated support for 10–20 high-potential UK companies to scale, attract investment, and remain UK-based.

Vision and targets

The plan envisions a dynamic ecosystem where science, capital, industry, and the NHS work will be uniting their strengths. By 2035, the UK aims to be a global leader in science, genomics, regulatory, and clinical research infrastructure. This will be enabled by a data ecosystem that drives research, diagnosis, with a strong focus on prevention. Our capital markets will support and fund entrepreneurs to scale, and - critically - our health system will adopt and scale innovation, from medicines to medtech and AI enabled technologies.

To measure progress, four key targets have been set:

Commercial R&D investment – Highest in Europe by 2030; globally (excluding US and China) by 2035.
Access to scale-up capital – More finance raised than any other European country by 2030, globally (excluding US and China) by 2035, with Initial Public Offerings and firms valued over £10 billion.
Patient access – UK to be among the top three fastest countries in Europe for access to medicines and medtech by 2030.
FDI – Highest life sciences FDI in Europe by 2030; globally (excluding US and China) by 2035.

Delivering the Plan: Execution

Each headline action has a named senior responsible officer to ensure accountability. Progress will be tracked through annual implementation updates. The Life Sciences Council, co-chaired by government and industry, will meet biannually to oversee delivery.

Impact of the UK Life Sciences Sector Plan on hVIVO

hVIVO is a leading full-service early-phase Contract Research Organisation, globally recognised for our expertise in human challenge trials. We offer end-to-end clinical development services, including virology and immunology lab support through our hLAB division.

hVIVO has expanded its service offering through the recent acquisitions of Clinical Research Services (CRS), enhancing our early-phase clinical trial services, and Cryostore, a specialist in high-quality, temperature-controlled storage solutions for biological and clinical materials. Venn Life Sciences, a subsidiary of hVIVO, contributes consulting and biometry expertise, while FluCamp supports patient recruitment. With five clinical trial sites, hVIVO offers a seamless pathway from preclinical research through to Phase III trials.

The UK Life Sciences Sector Plan positions the UK as a more efficient, data-rich, and sponsor-friendly environment for clinical research. This presents multiple strategic advantages for hVIVO:

Faster clinical trials – Reduction of trial setup times from ~250 to less than 150 days by 2026; aim to double participant numbers by 2029.
Innovative trial designs – Legislation supports adaptive, device, and decentralised trials through risk-based models and new methodologies.
Greater inclusivity – Public & patient involvement being formalised, with guidance on diversity targets to ensure underrepresented groups are included.
Regulatory reform and simplification – Launch a Regulatory Innovation Office to streamline MHRA approvals and uplift regulatory agility.

UK Life Sciences Sector Plan – A strong step forward

hVIVO is pleased to see the UK Government’s continued commitment to strengthening the life sciences sector through its latest strategic plan. With significant infrastructure investment and policy support, the UK is positioning itself as a global leader in life sciences innovation, research, and development.

hVIVO has established a working partnership with the Office for Life Sciences in support of their sector plan. Our Chief Executive Officer, Yamin Mohammed Khan, was recently featured in the UK Government’s life sciences sector plan press release.

As a company headquartered in the UK, we actively contribute to the strength of this ecosystem. The emphasis on building and expanding infrastructure within the UK not only reinforces the country’s reputation as a hub for cutting-edge science, but also creates exciting opportunities for collaboration, talent development, and long-term growth.

We are especially pleased to see the rise of Canary Wharf as one of the UK’s most dynamic life sciences communities. Our relocation to Canary Wharf places us at the heart of this emerging cluster, surrounded by world-class facilities, academic institutions, and fellow innovators. It is an inspiring environment that reflects the UK’s ambition to lead the future of life sciences.

The UK Life Sciences Sector Plan represents a major step forward in shaping a world-leading ecosystem for biomedical innovation, clinical research, and life sciences investment - one that hVIVO is proud to be part of.

Get in touch to explore how our expanded services and expertise can accelerate your drug development journey.

The UK Regulatory Competitiveness in an ever changing world

marketing@hvivo.com (Andrew Catchpole) — Fri, 10 Apr 2026 18:39:54 GMT

Clinical research success during the COVID-19 pandemic

The United Kingdom, with its rich history of clinical trials, has long been a preferred destination for conducting cutting-edge research. One of the key factors contributing to its attractiveness is the favourable regulatory environment, particularly when it comes to early development trials. Over the years, the UK has established itself as a frontrunner in clinical research, boasting a remarkable track record of achievements. Notably, it has played a pivotal role in recent successes, such as the rapid development of the COVID-19 vaccines and therapeutic trials.

The COVID-19 pandemic underscored the UK's prowess in clinical research, showcasing a dynamic collaboration between various stakeholders. This included the government, academic institutions, industry leaders, the National Health Service (NHS), and the public, all united in a shared mission to expedite the development of treatments for an urgent global health crisis.

Changes to Clinical Trials regulations

To reinforce its position as a global leader in clinical research, the Medicines and Healthcare products Regulatory Agency (MHRA), the UK's competent authority, unveiled a comprehensive plan earlier this year. This plan outlines significant changes to clinical trial regulations in the UK, with a primary focus on expediting key stages of the process.

Key changes proposed by the MHRA include:

Incorporating the MHRA/research ethics committee combined review into legislation: This step is set to establish competitive timelines for the review of trial applications, streamlining the process and reducing delays.
Streamlining reporting requirements and eliminating duplications: This initiative aims to enhance participant safety while minimizing administrative burden, making the UK even more attractive for clinical trials.
Introducing a 'notification scheme' for low-risk trials: Trials with risks akin to standard medical care will receive quicker approvals, eliminating the need for extensive regulatory review while ensuring that they are conducted in a risk-proportionate manner.
Reforming Request for Information (RFI) receipt: Sponsors will now have access to RFIs as they are ready, adopting a 'rolling review' approach, reducing waiting times and enhancing efficiency.
Enhancing risk proportionality in the trials process: The integration of risk proportionality into Good Clinical Practice (GCP) and other aspects of the trials process ensures that regulations align with the actual risk involved.
Streamlining and enhancing approval procedures: The MHRA seeks to make the process more efficient and competitive while maintaining international standards for trial conduct. This, in turn, will bolster the UK's position as a preferred site for multinational trials.

Notably, the MHRA has set ambitious timelines, with a goal of completing application reviews within a maximum of 30 days and making a final decision within a maximum of 10 calendar days after receiving responses to queries. These timelines stand in sharp contrast to the often lengthy processes in continental Europe under the EU Clinical Trial Regulation 536/2014, making the UK an ideal destination for early development trials, including Human Challenge Trials.

Elevating global clinical research leadership

In conclusion, the UK's commitment to enhancing its clinical trial landscape through regulatory reform not only reinforces its historical standing but also positions it as a global leader in clinical research. The streamlined and efficient regulatory framework, coupled with competitive timelines, makes the United Kingdom a top choice for researchers and organizations looking to conduct ground-breaking clinical trials.