I received an e-mail today from one of the many, many travel and tropical medicine listserves I am following. There has been recall of the YF vaccine manufactured by BioMaguinos, headquartered in Brazil. The recall is in response to the 4 Peruvian deaths associated with recent vaccinization, all from the same lot, of this implicated vaccine. Of note, there are 9 lots in total that are being recalled, at present. This larger recall, involving other lots, makes you wonder how widespread the problem vaccines are? This vaccine is widely used in South America.
According to the WHO/PAHO statement, 3 of the 4 deaths have been classified as “acute viscerotropic disease following yellow fever vaccination” after autopsy, with the 4th case pending. There have only been 37 cased of confirmed or suspected acute viscerotropic disease following yellow fever vaccination, since the disease was first recognized in 2001.
From that same WHO/PAHO statement: “The estimated risk for viscerotropic disease following YF vaccination ranges from 0.1 to 0.3 per 100,000 vaccinated persons overall; a higher risk has been documented in persons older than 60 years.”
The vaccine used in the USA is from a different company: Sanofi Pasteur.
The Yellow Fever vaccine is a live virus vaccine. This means you are actually getting a bit of the virus, that is alive, injected into you. There are other vaccines that make use of killed bacteria or viruses and inject them, letting your body develop immunity without risk of infection. The ubiquitus MMR (measles, mumps, rubella) vaccine is a live virus vaccine. Commonly given to children in developed nations, it is never to be given to people with weakened immune systems or pregnant women.
The Yellow Fever vaccine is given as a one shot dose and offers protection from YF for 10 years, according to WHO re-imminuzation requirements. I have commonly heard that the YF vaccine is believed to provide immunity for up to 30 years, although there is limited formal data to this.
Contraindications to receiving the YF vaccine include an altered or weak immune system (because you cannot fight off the live virus used to immunize you), pregnancy (the live virus can harm the fetus), allergy to eggs (the vaccine is produced by injecting the virus into eggs, allowing it to multiply) and age less than 9 months old (immune system might not be able to fight off the live virus).
Check out more about Yellow Fever over at AdventureDoc.org and my original post about this, a few days ago.