Since being approved in 2000, the pneumococcal conjugate vaccine (PCV) has become one of the regular childhood shots. Part of approving any new vaccine is keeping track of side effects; recently researchers at the Centers for Disease Control and Prevention reported on PCV.

What the researchers wanted to know: What side effects does the pneumococcal conjugate vaccine have, and how severe are they?

What they did: The researchers reported the first two years of PCV data from the voluntary Vaccine Adverse Event Reporting System, which the CDC and the Food and Drug Administration fill with information on side effects from manufacturers, patients, and healthcare workers.

What they found: Most of the side effects reported—85 percent‑were minor. But some were serious, including seizures and severe allergic reactions; 117 children died after having the vaccine. There were 13.2 reports per 100,000 doses of vaccine distributed.

What the study means to you: While some of the reported side effects probably were because of the vaccine, many probably weren't. Kids' usual bouts with rashes, diarrhea, and even seizures could easily coincide with a vaccination and be reported, even if they had other causes. And, as always, any possible side effects of a vaccine should be weighed against the benefits—in this case, preventing pneumococcal disease, the main cause of bacterial meningitis.

Caveats: Reporting adverse events to the government is voluntary, so many possible side effects probably don't get reported. That means you can't tell how common side effects are—this study just gives a rough estimate of how many are mild and how many are severe. Also, most children get multiple vaccines at a time, not PCV by itself.

Find out more: Information on this vaccine from the American Academy of Family Physicians

The CDC's immunization schedules for children and adolescents

Read the article: Wise, R.P., et al. "Postlicensure Safety Surveillance for 7-Valent Pneumococcal Conjugate Vaccine." Journal of the American Medical Association. Oct. 13, 2004, Vol. 292, No. 14, pp. 1702-1710.

Abstract online: http://jama.ama-assn.org