May 26, 2009

Vaccination Refusal Raises Risk Of Whooping Cough

Researchers said on Tuesday that one in 20 children whose parents do not get them vaccinated against whooping cough catch the highly contagious illness, Reuters reported.

Kaiser Permanente's Colorado Institute for Health Research showed in a government-funded study that only one in 500 children who got vaccinated developed whooping cough.

The study is the first to use medical records to confirm which children received immunizations and which ones did not, compared to the subsequent rates of whooping cough, or pertussis, researchers said.

Dr. Jason Glanz, an epidemiologist who worked on the study published in the journal Pediatrics, said although the illness is rarely fatal, it causes uncontrollable deep coughing and is especially dangerous for infants.

Whooping cough accounted for most of the 140 U.S. deaths from pertussis between 2000 and 2005.

However, an increasingly small proportion of parents are refusing vaccination shots for their children over fears about possible health threats such as autism "” raising the prospect that vaccine-preventable illnesses may reappear in clusters.

But history has shown that immunization has been credited with the eradication or control of smallpox, polio, diphtheria, measles, mumps and rubella.

Glanz said in a telephone interview that there were about 10,000 U.S. cases of whooping cough in 2007, so it was chosen to study the impact of vaccine refusals.

He said the U.S. immunization program has essentially become a victim of its own success, as it has been so successful at eliminating so many diseases that "we no longer see them."

He believes this has lead to more parents being worried about vaccine safety, since they're no longer worried about the diseases themselves.

Glanz suggested parents wrongly rely on "herd immunity" that assumes others will vaccinate their children so they do not have to, but the risk of an outbreak increases as more refuse to immunize.

The "tipping point" to an outbreak may be if immunization rates drop below 90 percent, he said.

Medical or religious exemptions are allowed in most U.S. states for not getting a child vaccinated. Some simply allow parents to refuse vaccinations out of a belief that they could harm their children.

Glanz said about 1 percent of U.S. parents get exemptions for their kids, but the figure is higher in some areas.

However, if children come out unscathed after surviving a bout with whooping cough, they can still spread illness-causing bacteria to more vulnerable victims, including babies not yet vaccinated.

Prevention of the illness requires five vaccination doses between 2 months and 18 months of age.

While most commonly employed vaccines are tightly regulated and monitored and are safe, Glanz said that does not prevent misinformation from circulating on the Internet and by word of mouth about supposed dangers.

"I'm hoping that our study is an additional piece of information that doctors can use when conveying the risks and benefits," he said.

He said that among the concerned groups of parents, some are on the fence and others are just staunchly anti-vaccine.

"As a father of young children, I understand that vaccines can pose confusing and difficult choices, so the purpose of this research is to give parents more information to weigh the benefits and risks, and to provide pediatricians with more information to help participate in the discussion," Glanz said.


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