The National Institute of Health on 27 July, 2016 announced trials for a new yellow fever vaccine. There is one currently available, but pregnant women, those over 60, infants, and the immunocompromised should not take it due to increased health risks.
Yellow fever caused 84000-170000 severe cases and approximately 50000 deaths in 2013 according to the World Health Organization. Infections appear to be on the rise in Africa. The hope is that the new vaccination will be effective and without side effects in the immunocompromised population.