The meningitis C vaccine program introduced in the UK in 1999 has been successful in bringing down disease rates. Now, new research indicates that vaccine remains effective 4 years later, provided that it was given at the appropriate age.

Meningitis is a potentially fatal condition that involves inflammation of the membrane covering the brain and spinal cord. Although the disease can arise from a number of causes, the most common is from bacterial infection. The vaccine protects against a bacteria called meningococcus C, one of the most common causes of meningitis in the UK.

The vaccine has proven effective in the short-term for reducing meningitis rates, senior author Dr. Mary Ramsay, from the Health Protection Agency in London, and colleagues note in The Lancet medical journal. The long-term effectiveness of the vaccine, however, was unclear.

Ramsay’s team addressed this issue by analyzing surveillance data collected 4 years after the vaccine program was implemented.

Vaccine effectiveness remained high for children who received the vaccine between 5 months and 18 years of age as part of a catch-up program. Although a drop in effectiveness did occur during follow-up, the overall effectiveness was still high - 90 percent - after 4 years.

In contrast, the vaccine’s effectiveness fell rapidly in children who received the vaccine between 2 and 4 months of age as part of a routine immunization program. The overall effectiveness for this group was just 66 percent.

This report provides “reassuring data,” Dr. Paul A. Offit, from the University of Pennsylvania in Philadelphia, and Dr. Georges Peter, from Brown Medical School in Providence, Rhode Island, note in a related editorial.

The results suggest that “a booster dose for young infants at 13 to 15 months of age would probably solve the challenge of waning immunity in infants vaccinated at 2, 3, and 4 months of age.”

SOURCE: The Lancet, July 24, 2004.