Whooping cough may be result of waning immunity
By REPORTER STAFF
Mercer Island Reporter Staff
July 23, 2012 · 1:29 PM
Reports from the United States Center for Disease Control indicate that the whooping cough outbreak in Washington state has the attention of the nation’s leading scientists.
The Washington State Secretary of Health declared a pertussis epidemic on April 3, 2012. By June 16, the reported number of cases in Washington in 2012 had reached 2,520 (37.5 cases per 100,000 residents), a 1,300 percent increase compared with the same period in 2011 and the highest number of cases reported in any year since 1942.
Consistent with national trends, high rates of pertussis were observed among infants under 1 year old and 10 years old.
However, the incidence in adolescents aged 13 to 14 years was also up, despite high rates of vaccination. Scientists believe this fact suggests early waning of immunity.
The pertussis vaccination remains the single most effective strategy for prevention of infection.
Researchers gathered information from patients about whether or not they had been vaccinated.
They found, in part, that as the children grew to adolescents, fewer had been vaccinated to the standard dosage level.
Through June 14, 2012, eight deaths have been reported in the United States, at a rate of 0.62 per 1,000 for reported cases. In comparison, 0.79 to 2.3 deaths per 1,000 reported cases occurred annually during 2000-2011.
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