Adults may not transmit whooping cough

ANN ARBOR, Mich., Nov. 12 (UPI) -- Transmission of whooping cough by adults may be minimal and adult vaccination is unlikely to be an efficient way to control the disease, U.S. researchers say.

University of Michigan epidemiologists Pejman Rohani, Xue Zhong and Aaron King combined two independent sets of data from previous studies and found age-specific contact patterns alone can explain the observed shifts in prevalence and age-specific incidence.

Data from Sweden were used because infants had been routinely vaccinated for nearly 30 years, but after concerns about the led to a halt in whooping cough, or pertussis, vaccination was discontinued in 1979. It resumed in 1996 using a different vaccine.

The second set of data was from a 2008 study in which more than 7,000 people from eight European countries kept track of all the contacts they had with other people during one day, recording the age and sex of the person they interacted with, where the interaction took place and the duration and type of contact -- such as conversation or physical contact. This study found children interacted far more frequently with other children than with adults.

The researchers stress that since the study used incidence data from Sweden, the results may or may not apply to the United States, where infant vaccination compliance rates are lower and the population more diverse.

"We need similar analyses for the United States," Rohani says.

The findings are published in the journal Science.