Hepatitis B Vaccine Linked to Onset of Diabetes
Investigators compared 150,000 children who had been vaccinated at age 3 months to an equal number of unvaccinated children. To assess the risk of developing type 1 diabetes in children who got the vaccine later, after vaccination became mandatory in Italy, 400,000 children who were vaccinated at age 12 were compared with children who had not been vaccinated.
In the group as a whole, the rates of type 1 diabetes were 46 per 100,000 for children who had been vaccinated and 34 per 100,000 for children who had not. For those vaccinated at age 12, the rates were 17.8 per 100,000 for vaccinated children and 6.9 per 100,000 for unvaccinated children.
Although these may seem like large groups to study, they are not big enough for scientists to see clear patterns for type 1 diabetes, Rewers says. For a study like this to have value, the database should involve as many as 250,000 people in both the vaccinated and unvaccinated groups, he says.
"Caution is necessary when the potential of vaccine-related risks is studied," Rewers tells WebMD. "Without sound supportive data, [parents] can become unduly alarmed and stop immunizing their children." When immunization rates drop, diseases that can cause serious illness -- and death -- return, he tells WebMD.
The National Institutes of Health and the CDC are jointly establishing a system known as "sentinel monitoring areas," Rewers tells WebMD. The agencies will track the rate of type 1 diabetes in these areas -- consisting of selected counties in the U.S. -- and will determine whether the rate is related to things like immunizations, recommended infant feeding schedules, and outbreaks of infection.
Rewers has not been involved with the development of any vaccine and has no ties to any company that manufactures vaccines.