Combo Vaccine Linked To Kids' Convulsions

ProQuad Protects Against Measles, Mumps, Rubella, Chickenpox
February 28, 2008

ATLANTA (AP) -- A new study finds children suffered higher rates of fever-related convulsions when they got a Merck combination vaccine instead of two separate shots.

The results prompted a federal advisory panel to back away from its preference for the combo vaccine ProQuad, which protects against measles, mumps and rubella as well as chickenpox.

In the study of children ages 12 months through 23 months, the rate of seizures was twice as high in toddlers who got ProQuad, compared with those who got one shot for chickenpox and one for the three other diseases.  

The lead researcher of the federally funded study said the risk translates to about one extra case of convulsion for every 2,000 doses of the combo vaccine.

The study focused on children who develop fevers and then go into convulsions. It's an occurrence that frightens parents but usually has no lingering consequences. There were no deaths in the new study.