A small study from Italy has found that immunity to whooping cough is short lived after either vaccination or natural disease.
Researchers from the University of Milan evaluated 38 children, aged 5-6 years, who had been immunised three times by age 11 months with a combined diphtheria, tetanus, tricomponent acellular pertussis and hepatitis B (DTaP-HBV) vaccine.
Their immune responses were compared with those of 21 children who had acquired pertussis during their first year of life and who had received only a diphtheria, tetanus and hepatitis B (DT-HBV) vaccination. The immunity to pertussis was similar in both groups.
The authors recommend that previously vaccinated or infected children receive a booster to maintain long term immunity (Infect Immun, 2001; 69: 4516-20).