BOSTON (Reuters) - Merck's chickenpox vaccine Varivax not only loses its effectiveness after a while, but it has also changed the profile of the disease in the population, U.S. researchers reported on Wednesday.I have spoken out against the chickenpox (varicella) vaccine mandate as one that is unnecessary and may be causing more harm than good. It is much better for people to get chickenpox as kids than adults, and the vaccine leaves adults without the immunity they need.
The study confirmed what doctors widely knew -- that the vaccine's protection does not last long.
And with fewer natural cases of the disease going around, unvaccinated children or children in whom the first dose of the vaccine fails to work have been catching the highly contagious disease later in life, when the risk of severe complications is greater, they said.
"If you're unvaccinated and you get it later in life, there's a 20-times greater risk of dying compared to a child, and a 10 to 15 times greater chance of getting hospitalized," said Jane Seward of the Centers for Disease Control and Prevention in Atlanta, who worked on the study.
The findings, reported fully for the first time in Thursday's New England Journal of Medicine, have already had an impact.
They helped prompt the CDC's Advisory Committee on Immunization Practices to recommend a booster shot between the ages of 4 and 6. The panel also said in its June 2006 report that children, adolescents and adults should be given boosters as well.
No one knows how long the effects of a second shot will last, said the research team, led by Sandra Chaves of the CDC.
Saturday, March 17, 2007
Chickenpox vaccine endangers adults
Here is some new CDC research: