Meningococcal meningitis group A: a successful control of an outbreak by mass vaccination

Jeddah is the main point of entry to the holy places in Saudi Arabia. An outbreak of meningococcal disease (MCD) occurred during the fasting lunar month for Muslims, Ramadan (March-April) of 1992. To assess the threat of local spread of MCD within Jeddah, the effects of previous and a mass vaccination programme against MCD during the outbreak, we reviewed the medical records of confirmed cases (CC) of MCD (defined as a bacteriologically confirmed case or a case diagnosed by latex test) and their vaccination status in the last five years before the outbreak. There were 41 CC of meningitis due to Neisseria meningitidis (group A). The ratio of males to females was 4.1:1. Thirty two percent of the cases were religious visitors. About one fourth (22%) of the cases were Pakistani. More than half (57%) of the cases, who were residents of Jeddah, lived in the north-eastern part of the city, as did half of the Pakistani cases. The case-fatality rate among CC was 19.5%. Persons who visited the Makkah (Mecca) during Ramadan were more likely to get the disease than those who did not (odds ratio [OR] = 6.1; 95% confidence interval [CI] 1.4-40.7). Unvaccinated persons were more likely to get the disease than those who were vaccinated against MCD (OR = 13.9; 95% CI 1.8-296). Meningococcal vaccine (MCV) against MCD was effective in preventing the disease. However, MCV was of no protective value if it had been administered more than five years before the outbreak. The reason mentioned most frequently for not being vaccinated by both cases (84%) and controls (57%) was lack of knowledge about the disease. Health education programmes should be strengthened and promoted. A good collaborative surveillance system between Jeddah and other holy cities, especially Makkah, is needed to abort outbreaks among religious visitors and to prevent the spread of MCD outbreaks.