NINE babies have died in California, and four in Australia, so far, in the worst epidemic of whooping cough in rich countries since vaccination became widespread in the 1950s. The main cause is a lack of re-vaccination, but the bacterium may also be adapting to beat vaccines.
Vaccination protects babies 鈥� these recent deaths have been in babies not yet vaccinated 鈥� but immunity wanes with age, so older children and adults can be unwittingly infected with whooping cough and infect unvaccinated babies. California is that don鈥檛 require re-vaccination of children entering secondary school. It is now offering vaccine to anyone over 7.
Yet waning immunity doesn鈥檛 explain why whooping cough, or pertussis, has climbed steadily in Europe and North America since the 1990s, says Frits Mooi of the Dutch National Institute for Public Health and the Environment in Bilthoven.
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Vaccines are still made with strains isolated before the 1950s, he says. Mooi has evidence that circulating pertussis bacteria are mutating to evade vaccines, and producing more of a toxin .
鈥淲hooping cough bacteria currently in circulation appear to be mutating to evade vaccines鈥�
鈥淚f confirmed, it will be the first known case of a human disease germ adapting to vaccination,鈥� says William Schaffner, head of preventive medicine at Vanderbilt University in Nashville, Tennessee.
