Local research with global impacts – human challenge trials making a difference
Advancing our knowledge of disease, and improving how we protect against it.
What we learn from human challenge trials can push us closer to finding better methods of protecting against disease, like improved vaccines. The impacts reach around the world.
What we learn from human challenge trials can push us closer to finding better methods of protecting against disease, like improved vaccines.
In many cases, those who are most impacted by disease are children, the elderly, the immunocompromised, pregnant people, and those who don’t have access to high-quality healthcare or reliable sanitation. The advancements in vaccines and treatments that human challenge trials make possible benefit these groups the most. The impacts of what we learn from human challenge trials reach around the world.
What we’ve learned from human challenge trials
Pneumonia
Pneumonia causes about 2.5 million deaths a year. Those who are young, elderly, or immunocompromised are the most likely to experience severe disease from the infection. There are vaccines that can protect these groups, but there are many different strains of the bacteria that causes pneumonia, and the vaccines don’t protect against them all.
Researchers in the UK conducted a challenge study to better understand how our immune system responds to these bacteria, and what gives us immunity to the infection. They were able to discover some important clues about which cells are the most important to a successful immune response to the bacteria. Previous studies conducted ethically in animals had seemed to point towards a different kind of cell as a key player. This clearer understanding could help researchers design more effective vaccines.
Typhoid
Typhoid fever causes close to 130,000 deaths each year. The disease disproportionately affects low- and middle-income countries.
Some bacteria produce a molecule called a toxin that can help them enter the body, evade the immune system, and more. The bacteria that cause typhoid fever produce these molecules, but researchers haven’t been able to determine exactly what role these typhoid toxins play in typhoid fever. The disease is different in mice than in humans, making it harder to figure this out from animal trials.
Results from a challenge study at the University of Oxford suggest that the toxin’s role may have to do with concealing the bacteria from the immune system. More research will be needed to understand the exact role, but these results will help get us closer to that answer. This knowledge could also help us understand why the bacteria remains in some people even after recovering from the illness, which is part of how the bacteria continues to spread.
Influenza
The flu can be a more serious illness for seniors, the very young, or those with certain health conditions.
Influenza, or flu, is a common virus impacting many people each year. It can be a serious illness for people from vulnerable populations like the elderly, the very young, or those with certain health conditions. Annual flu vaccines are an important part of protecting these groups against the flu. However, current vaccines and drugs aren’t always 100% effective.
A challenge study in London tested a potential new drug as a treatment against the flu. The results indicated that the drug both reduced symptoms and limited how much the virus was able to make copies of itself to continue spreading. The new drug has now moved on to the next phase of development and is one step closer to being able to help protect others from serious illness caused by influenza.
Other studies have examined new combination vaccines for Malaria, helped us learn more about COVID-19 and what dose of the virus should be used in future trials, and more.
Advancing our knowledge of disease
Human challenge trials and the volunteers that take part in them will continue to make a difference felt in our communities and around the world.
Human challenge trials are an important tool that have been in use for decades. They have helped researchers learn more about the early immune response and test new vaccines and treatments and have played a significant role in strengthening global knowledge of how to best protect against severe disease.
Advancements in vaccine technologies and treatments for diseases, including those made possible by challenge trials, have helped prolong lives globally.
Where longstanding questions about disease remain, and the impacts of illness persist, future challenge studies will help us solve those mysteries. Human challenge trials and the volunteers that take part in them will continue to make a difference felt in our communities and around the world.