The 12 month phase 3 data indicates 75% vaccine efficacy of R21 in annual malaria sites in children at 12 months after the first dose was delivered. Phase 2b data at a 42 month timepoint showed 71% efficacy after four total doses (Abstract here, #6949).
Resolves upon publication of peer-reviewed data from the R21 team at Oxford (expected to be before September 1st, 2025).
Vaccine efficacy is defined as the primary endpoint for time to clinical malaria in seasonal sites, as defined in the paper linked above.
1Day Sooner has an R21 Status Report available here that may be useful.
More malaria-related questions can be found on our Manifold account here.
1,000This says 71-73%
"Efficacy (reduction in clinical malaria episodes) data revealed high rates 67-75% over 12 months for standard and seasonal sites, with similar efficacy (66-76%) up to 18 months post 4 doses and maintained efficacy of 71-73% at seasonal sites over 24 months"
