[Changes in epidemic features of epidemic cerebrospinal meningitis after vaccination with purified meningococcal polysaccharide vaccine group A in Zhengzhou].

The authors studied the epidemic features of epidemic cerebrospinal meningitis before and after mass vaccination with Purified meningococcal polysaccharide vaccine group A. After the mass vaccination, the morbidity rate of epidemic cerebrospinal meningitis fell considerably year after year. The epidemic cycle changed for the first time. The ratio of the number of cases in the city to those in the countryside was reduced. The phenomenon that the infectious disease spread along traffic lines from city to countryside disappeared. The cases mainly occurred in the remote mountain village. The morbidity rate in the group of 0-3 years relatively increased. The level of antibody titers in population obviously increased. The carrier rate of meningococci and constituent ratio of group A reduced. The epidemic group was group A, but cases of group C occurred for the first time.