Extensively Drug-Resistant Typhoid — Are Conjugate Vaccines Arriving Just in Time?

New England Journal of Medicine
October 18, 2018   Vol. 379 No. 16

Extensively Drug-Resistant Typhoid — Are Conjugate Vaccines Arriving Just in Time?
Jason R. Andrews, M.D., Farah N. Qamar, F.C.P.S., Richelle C. Charles, M.D., and Edward T. Ryan, M.D.
We are in a critical period. XDR S. Typhi has appeared in a densely populated area of Asia. The growth of informal settlement areas lacking adequate sanitation and water infrastructure will most likely fuel its transmission, and international migration and travel could facilitate its spread. The good news is that an effective typhoid conjugate vaccine is now available and can be used to augment typhoid-control efforts. The Typbar TCV vaccine is now being used in the outbreak response in Hyderabad, though the strain had already spread beyond the vaccine target area and may continue to disseminate.
The new WHO recommendation, availability of a prequalified vaccine with durable immunogenicity that can be given to young children, and the Gavi funding commitment provide more favorable conditions than have ever before existed for countries to incorporate typhoid vaccines into immunization programs. To guide these efforts, we need to invest in improved surveillance efforts and accelerate conjugate vaccine introduction in countries where the burden of typhoid is known to be high. Whether we will take the necessary action before the window closes is still uncertain.