Yellow fever is a viral disease that is transmitted by infected mosquitos. It is mainly found in tropical areas in Africa and South America. Although the current yellow fever vaccine is highly effective with a single dose, vaccine supply is limited.
When outbreaks happen during vaccine shortages, the World Health Organization recommend using a lower dose, but there is currently a lack of research on how effective it is at causing an immune response.
The team at KEMRI Wellcome Trust Research Programme conducted a randomised, double-blind trial in Uganda and Kenya, using 480 volunteers without a prior history of yellow fever or the vaccine. The main goal was seroconversion 28 days after receiving the vaccination, with each of the three smaller doses. The results showed that a dose as low as 500 IU was noninferior, compared to the standard dose of 13,803, regarding the goal of seroconversion at 28 days after vaccination.
To read the full paper, visit the New England Journal of Medicine website: https://www.nejm.org/doi/10.1056/NEJMoa2407293