The meningitis C vaccine program introduced in the UK in 1999 has been successful in bringing down disease rates. A recent study 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. Researchers from the Health Protection Agency in London analysed surveillance data collected 4 years after the vaccine program was implemented and found that the vaccine has proven effective in the short-term for reducing meningitis rates, the long-term effectiveness of the vaccine, however, was unclear. 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 per cent 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 per cent. 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.
The Lancet,
June 2004