Yellow fever vaccine only for those at high risk of exposure
DEAR DR. ROACH — My husband and I are taking a cruise around South America that includes several stops in Brazil. We both are 72 and in good health. What is your opinion about our getting the yellow fever vaccine? According to the Centers for Disease Control and Prevention, it “should be given cautiously to people older than 60.” I don’t understand why. — P.M.
ANSWER — The yellow fever vaccine, which in the U.S. can be given only at specially accredited travel clinics, has significantly higher risks, compared with routine vaccines. Most people do very well, with between 5 and 30 percent of people having a mild reaction that includes fever, headache and muscle ache, beginning a day or two after the vaccine and lasting a week or so.
About 2 people per 100,000 will develop anaphylaxis, the most severe immediate reaction. It requires emergency treatment. Clinics that give the vaccine must be prepared to recognize and treat anaphylaxis, and recipients need to stay at least 15 minutes after the vaccine to monitor for it.
However, there are two rare and potentially fatal conditions associated with yellow fever vaccine: One causes inflammation of the brain (encephalitis) and its lining (meningitis); the other causes a condition similar to yellow fever, called yellow fever vaccineassociated viscerotropic disease. Because people over 60 are at higher risk for adverse effects, it should be given only to those with high risk for exposure to yellow fever. Fortunately, the risk for these complications is still low: Perhaps 5 older people per 100,000 who get the vaccine get a serious complication, and perhaps 5 per million get the worst complication, viscerotropic disease.
Some parts of Brazil are experiencing a yellow fever outbreak now, so it’s very important that you check your travel itinerary with the information available at wwwnc.cdc.gov/travel/ notices/alert/yellow-feverbrazil. Not all travelers to Brazil will need the vaccine. Many cruise lines avoid areas with high risk of yellow fever.
Further, there is a shortage of the only licensed vaccine available; a different (but similar) vaccine may be available. If you decide to get the vaccine, you should find a yellow fever travel clinic well ahead of time. The vaccine has risks, but yellow fever has a mortality rate at least 5 to 10 percent, and up to 50 percent for those with severe disease. People with risk for getting yellow fever are more likely to benefit from than be harmed by the vaccine, despite its risks. People with zero risk of getting the disease, however, do not benefit.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to: ToYourGoodHealth@med. cornell.edu. Health newsletters may be ordered from www.rbmamall.com.