Immunity wanes after vaccination against whooping cough

JAMA2012;308:2126-32OpenUrlCrossRefPubMedWeb of Science

There is a growing feeling among experts that modern acellular vaccines against Bordetella pertussis are not as durable as the old whole cell ones. A case-control study of children from California seems to support this theory, with odds of infection rising and vaccine efficacy falling with each year since completion of the vaccination schedule. Estimated efficacy of five doses of the acellular vaccine fell from 98.1% (95% CI 96.1% to 99.1%) in the 12 months after the last dose to 71.2% (45.8% to 84.8%) after five years.

The authors compared the vaccination histories of 682 people reported to have whooping cough with 2016 uninfected controls. All were recruited in 2010, during the biggest outbreak for 60 years, in which 10 infants died. This study and others were launched in response to particularly high rates of whooping cough among preadolescents, despite high coverage of the recommended DTaP (diphtheria, tetanus, and acellular pertussis) vaccine.

The new analyses add to other circumstantial evidence from California and elsewhere that current vaccine strategies aren’t working for long enough to protect vulnerable groups of older children, says a linked editorial (p 2149). Whooping cough can be serious for these children and deadly for any young unvaccinated infants who they come into contact with. Better vaccines might be needed in the long run. Meanwhile, public health authorities should consider redesigning schedules to make smarter use of the vaccine that we have, which works considerably better than nothing.