Deaths Tied to Yellow Fever Vaccine
Monath suggests that some people may carry an extremely rare genetic susceptibility that renders them likely to contract the illness when vaccinated. Others have questioned whether differences in the viral strains used to make the vaccine, contamination, or other factors account for events
And why are the reports surfacing now, when the vaccine has been in use for decades?
Public health experts suggest that better monitoring and reporting of bad reactions to vaccines and drugs may have helped turn up cases that have been missed in the past.
Martin Cetron, MD, an author of the CDC report, says more than 250,000 doses of the vaccine are dispensed in the U.S. each year, and the likelihood of serious problems is only one in 400,000.
"We are talking about something which is so infrequent that one might not see a case but every year or so," says Cetron, deputy director of the division of global migration and quarantine at the CDC.
Monath urges travelers to receive the vaccine only if they are traveling to the areas where yellow fever is commonplace -- including tropical South America or sub-Saharan Africa. However, he notes that some other countries may require proof of vaccination to enter, especially if they are passing through areas where the disease is rampant.
At the same time, Monath says travelers headed to dangerous areas are being under-vaccinated. And both he and Cetron urge travelers to recognize the life-threatening nature of yellow fever.
"If you are traveling in an area of ongoing transmission, such as Western Africa or the Amazon, your risk of getting yellow fever unprotected by vaccine is many times higher than your risk of [having problems] from the vaccine," says Cetron.