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NEW YORK (Reuters Health) - Whooping cough has been unusually common in Seattle-area babies in recent years. Now a new report suggests the problem could be corrected by encouraging vaccination of the people who care for them.
In the Seattle area between 2002 and 2007, 136 out of every 100,000 infants developed whooping cough each year, on average. Among every 100,000 U.S. infants overall, however, only 97 developed whooping cough in 2005.
In their study of Seattle babies who came down with whooping cough, the researchers found that nearly half the people who lived or worked with the babies were eligible to receive a vaccine that would have protected them -- and maybe the babies, too -- from the illness, according to a report published in the Archives of Pediatrics and Adolescent Medicine.
The incidence of whooping cough, also known as pertussis, "varies from year to year in different areas of the U.S.," said Dr. Tina Q. Tan at Children's Memorial Hospital in Chicago, who reviewed the findings for Reuters Health.
"There needs to be more educational efforts targeted at adult physicians and health care consumers on the major public health burden that pertussis continues to be and the importance of vaccination as a means of prevention," Tan said in an email.
Whooping cough causes uncontrollable, violent coughing, infects 30 to 50 million people a year globally and kills about 300,000, mostly children in developing countries.
There are regular outbreaks in developed countries. The problem may be getting worse because some parents have been reluctant to vaccinate their children -- and the more unimmunized people there are in a community, the more likely there are to be outbreaks. One recent whooping cough outbreak in California has affected more than 6,400 people and killed at least 10 infants.
None of the infants in Seattle died from whooping cough, but nearly half were hospitalized. Among those hospitalized, 1 in 5 needed to be in an intensive care unit.
Seventy-seven percent of infected infants in Seattle had already been partly vaccinated. However, children need to receive a series of shots to be completely vaccinated, and most babies who get sick with whooping cough aren't old enough to have completed the entire series of injections.
Consequently, in 2008 health officials, including the American College of Obstetricians and Gynecologists, recommended that new mothers receive a new "Tdap" vaccine for tetanus, diphtheria and pertussis designed for older children and adults. Protecting the mothers would keep the germs away from the little ones, too.
And late last month, the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention in Atlanta voted to update that advice, saying that new mothers should receive Tdap during pregnancy, rather than immediately after giving birth.
Approximately 50 percent of household members and people in regular contact with the infants who developed whooping cough would have been eligible for the Tdap vaccine -- and receiving it may have prevented the infants from developing the infection in the first place, the authors argue.
The Tdap vaccine costs about $30. Insurance plans generally cover it for new mothers, and Medicare covers it for grandparents and other older adults.
Dr. Cameron Grant of the University of Auckland in New Zealand, who also reviewed the findings for Reuters Health, agreed that kids and adults in contact with infants should receive the Tdap vaccine. Since it takes a few shots for infants to have full protection themselves, preventing whooping cough in "close contacts will reduce the risk of spread of pertussis from these contacts to the infant," said Grant, who noted he has received funding from and attended meetings sponsored by companies that produce the Tdap vaccine.
It's not clear why Seattle babies had a higher risk. Study author Dr. Matthew P. Hanson of the Bill & Melinda Gates Foundation and his colleagues note it may stem from better diagnosis of the disease, better reporting of cases when they occur, or regional differences.
It's also not clear why infants from minority groups were more likely to develop whooping cough. For instance, African-American babies had more than triple the risk of white babies. "There could be several reasons" for this pattern, Grant said in an email. Black or Hispanic infants may spend more time with extended family, or have less access to health care and therefore receive fewer immunizations, he suggested.
SOURCE: bit.ly/kEg36P Archives of Pediatrics & Adolescent Medicine, July 2011.