Surveillance of measles, pertusis, diphtheria and tetanus among healthy population in Shengsi islands, 2007

ObjectiveTo evaluate the vaccination efficacy and herd immunity in Shengsi islands. MethodsThe surveillance of measles, pertusis, diphtheria and tetanus antibody level were conducted among 248 healthy people (including the people from other palaces) by a random sampling, specific IgG of measles was detected by micro hemagglutination inhibition test, agglutinating antibody of pertusis were detected by tube agglutination test and antitoxins of diphtheria and tetanus were detected by indirect hemagglutination test. ResultsAmong this healthy population, the measles antibody positive rate was 72.18%, pertusis antibody positive rate was 80.74% and the protection rate was 32.38%, diphtheria antibody positive rate was 54.25% and the protection rate of tetanus antitoxin was 72.18%. ConclusionThe herd immunity level of vaccines is insufficient, which might be related with non-fully vaccination of some children among floating population, the change of vaccination schedule and doses, poor cold chain for vaccine transportation and the decrease of quality of some vaccines.