Expanding Challenge Studies to Other Diseases

While challenge studies are not appropriate for every disease, they can be useful for many. We support and advocate for the development of novel challenge models for various diseases worldwide, as well as the continued implementation of challenge models that have already been established.

Hepatitis C

1Day Sooner is actively working with researchers in North America and the United Kingdom to realize the first ever challenge studies for hepatitis C, a viral liver disease that nearly 60 million people live with worldwide. Hepatitis C is fully treatable, but there is no vaccine, and as a bloodborne disease, it is exceedingly difficult to conduct field trials for vaccine efficacy.

Read more about why we think challenge studies are the best route for a vaccine here — and how you can express preliminary interest in volunteering if they are approved in your area!

Group A Strep

While often thought of as just a pesky sore throat, group A streptococcus (strep A) infections kill hundreds of thousands of people per year. 1Day Sooner founder Josh Morrison knows this all too well, having lost a relative to strep A. We are supporting the implementation and recruitment of strep A challenge trials in Australia, and believe they hold great promise for an eventual vaccine. Read more about strep A and the strep A challenge model here.


Tuberculosis (TB) kills more people than any other disease besides COVID-19. Given the enormous numbers of people that TB affects and the dangers of TB, developing a safe and effective TB vaccine would be a historic achievement. 1Day Africa has liaised extensively with the ongoing efforts to establish safe challenge studies in Malawi, where TB burden is extremely high.