INTRODUCTIONPertussis is a highly communicable, vaccine-preventable respiratory disease and a frequent but often underestimated cause of prolonged cough illness in adults. Protection after childhood vaccination is minimal after 10 years without boosting. The need for adult booster depends on the national epidemiology.

MATERIALS AND METHODSWe did a seroepidemiological survey amongst the adult population (aged 18 to 45 years) of Singapore. None had received pertussis booster vaccine in the preceding 10 years. We measured IgG antibodies to pertussis whole cell antigen.

RESULTSTwo hundred and seventy subjects with the median age of 30 years were enrolled. We found positive IgG antibody levels in 97% of the population. Seropositivity was not associated with age, gender or race.

CONCLUSIONThe seroprevalence in adults was much higher than the previously documented seroprevalence of around 50% in the adolescent age group in Singapore. The increase is most likely due to natural infection with B. pertussis. Pertussis booster vaccine for adolescents/young adults in Singapore would be indicated.

Adolescent ; Adult ; Antibodies, Anti-Idiotypic ; immunology ; Antibodies, Bacterial ; blood ; Bordetella pertussis ; immunology ; Cross-Sectional Studies ; Diphtheria-Tetanus-acellular Pertussis Vaccines ; pharmacology ; Female ; Humans ; Immunoglobulin G ; immunology ; Male ; Middle Aged ; Population Surveillance ; methods ; Prevalence ; Prognosis ; Retrospective Studies ; Seroepidemiologic Studies ; Singapore ; epidemiology ; Whooping Cough ; epidemiology ; immunology ; prevention & control