Young people who get a new meningitis shot may be at a slightly higher risk of developing a paralyzing side effect, federal researchers said. Even so, U.S. health officials said the benefits far outweigh the risk of getting the rare condition, Guillain Barre syndrome. They are not backing off their recommendation that most students be vaccinated.
The researchers cautioned that they are uncertain about their risk estimate, and a larger study is being planned.
They found the added risk was 1.25 cases of GBS for every one million doses of vaccine distributed.
“It’s a very small risk,” said one of the study’s authors, Dr. Robert Davis of the U.S. Centers for Disease Control and Prevention, who noted the risk of getting meningitis without the shot is far greater.
A U.S. federal vaccination advisory committee is to discuss the research next week when it takes a new look at the government’s meningitis vaccine recommendations, CDC officials said.
The research was reported Thursday in the CDC’s Morbidity and Mortality Weekly Report.
The vaccine, Menactra, is made by Sanofi Pasteur, which said it tested it in more than 10,000 people. The company reported no cases of Guillain-Barre, or GBS, which is characterized by increasing weakness in the legs and arms, sometimes severe enough to cause paralysis.
The vaccine is licensed for use in Canada but is not yet in distribution, said Nancy Simpson, a spokesperson for the company’s Canadian operations.
The U.S. government approved it for marketing in January 2005, and the CDC recommended it for routine vaccination four months later.
About 6.6 million doses had been distributed through the end of September, according to Sanofi.
The CDC recommends the vaccine for students when they enter high school and college. In particular, college freshmen living in dorms are urged to get the shot because close contact is a major risk in the spread of bacterial meningitis. People ages 15 to 24 have some of the highest mortality rates. Survivors can suffer mental disabilities, hearing loss and paralysis.
Between March 2005 and September 2006, 17 people developed GBS within six weeks of receiving the vaccine. Fifteen of those were 11 to 19 years old.
Scientists expect a small number of GBS cases to occur naturally, so the researchers calculated an expected rate of cases and compared it to the rate in the vaccinated people.
Death or serious illness from bacterial meningitis occurs at an annual rate of about 1.2 cases per 100,000 youths ages 11 to 19, said Davis, director of the CDC’s immunization safety office.
That means the risk of an unvaccinated youth getting seriously ill from bacterial meningitis is about 10 times greater than the risk of a vaccinated youth developing GBS, according to the study.
A larger study that would give a more accurate picture of the risk is being discussed with the vaccine maker, Davis said.