Whooping cough vaccine: Unvaccinated children behind outbreak

Parents who fail to vaccinate their kids for nonmedical reasons against whooping cough are the cause of the bacterial infection's outbreak, a new study says.

Researchers found that incidence of whooping cough was 2.5 times more likely in areas where parents exempted their kids from vaccinations.

Nonmedical vaccine exemption not only puts kids at risk of contracting the contagious disease, but their peers and families as well, the researchers noted.

"Not vaccinating your child is not a benign decision. It has real health consequences to the individual child and to the community," explained study senior author Saad Omer, an associate professor of global health, epidemiology and pediatrics at Emory University in Atlanta, to HealthDay.

Whooping cough, also known as pertussis, attacks the respiratory system and is highly contagious. The U.S. Centers for Disease Control and Prevention reported 48,000 cases and 18 deaths, mostly among infants, from the disease in 2012.

To prevent the disease from spreading, it's important the kids get vaccinated on schedule, the researchers said, explaining its resurgence can partially be blamed on the new version of the vaccine, which doesn't last as long as the old vaccine.

Omer and his team studied vaccine exemptions from school data and whooping cough outbreak. The risk of whooping cough was 20 percent higher inside a vaccine exemption cluster - they found 39 such areas - than outside of one, according to the results.

The 2010 whooping cough outbreak in California affected 9,120 people and resulted in 10 deaths. The largest outbreak since 1947, the event brought the issue into the spotlight.

Study authors noted that in California's case, vaccine exemptions rose from 0.77 percent in 2000 to 2.33 percent in 2010, although about 91 percent of kindergarteners that year had received all the necessary immunizations.

"It's personal freedom versus public health," noted Dr. Kenneth Bromberg, director of The Vaccine Research Center and chairman of pediatrics at The Brooklyn Hospital Center in New York City.