by Matt Rosenberg July 23rd, 2012
The headline-grabbing outbreak of whooping cough, or Pertussis, in Washington state this year affected Hispanics at a rate more than twice that of non-Hispanics, according to a new report from the Washington State Department of Health and U.S. researchers that was published late last week by the U.S. Centers for Disease Control in the CDC’s journal Morbidity and Mortality Weekly Report. The report “Pertussis Epidemic – Washington 2012″ found that in the large percentage of cases where ethnicity and race were known, that “statewide cumulative incidence was higher in Hispanics than non-Hispanics (53.1 versus 24.6 cases per 100,000 population).”
By age, infants under less than one year, plus children ages 10, 13 and 14 had the highest incidence of whooping cough during the statewide epidemic.
Through June 16 of this year the overall number of reported cases in Washington State was 2,520, or 37.5 per 100,000. That was a 1,300 percent increase over the same period here last year and the most reported in the state since 1942. The state’s rate to almost mid-year 2012 was also nine times the national rate of 4.2 per 100,000 during the same period. However researchers stress Pertussis rates for key populations of infants, 10-, 13- and 14-year-olds also rose nationally in that time.
Underscoring parallel concerns at the national level, total cases of whooping cough to date in 2012 in the U.S., at almost the mid-year point, were higher than in any of the five previous years as “a gradual and sustained increase” has developed nationally since historic lows in the 70s.
Researchers looking at recent Washington State and U.S. data wrote that they were especially concerned at the increased incidence of whooping cough among 13- and 14-year-olds, despite how many were vaccinated. Outcomes are suggesting “early waning of immunity,” in what they say is a national trend.
As many as one-third of young adolescents in Washington state and the U.S. who got the common Tdap vaccination including protection against Pertussis, and who had received other vaccines against whooping cough earlier in their lives, still were susceptible to Pertussis after administration of Tdap, according to the report.
The vast majority of whooping cough cases in Washington state involved children one year of age or older and fewer than one percent of those were hospitalized because of their pertussis. Children less than year with Pertussis were hospitalized at a higher rate, of almost 22 percent. But none in either age category were reported to have died as a result of Pertussis.
State and U.S. health authorities strongly recommend renewed Pertussis vaccinations for adolescents and adults, especially pregnant women.