Researchers in Colorado have found a link between a parents decision not to vaccinate their children and increased rates of pertussis -- a diagnosis also known as whooping cough.

In findings reported in the journal Pediatrics, investigators reported on the results of a case-control study of 156 children with laboratory confirmed cases of whopping cough and 595 children without the diagnosis who had received health management services at Kaiser Permanente of Colorado between 1996 and 2007.

Data showed that children who had not received vaccinations were at a several hundred-fold increased risk for whooping cough compared children who had been vaccinated. More than one in ten children who had not been vaccinated were diagnosed with the condition compared to about one in 200 children who had been vaccinated.

Pertussis, or whooping cough, is caused by bacteria that leads to severe coughing fits and can be so bad that it can cause choking and vomiting. Although it can be treated with antibiotics and typically lasts about a week to ten days (or about 2-weeks in unvaccinated children), severe complications can occur during the active phase and include pneumonia, emphysema, severe weight loss, vomiting, bleeding in the brain (cerebral hemorrhage), seizures, infection of the lining of the brain (encephalitis), and death. Whooping cough is extremely contagious during the first five days of infection.

Because of potential of severe complications and the contagious nature of the infection, many children diagnosed with whooping cough are hospitalized during the active phase. Before a vaccine was discovered, whopping cough was one of the leading causes of death among children in the United States.

The study provides further evidence of the risks associated with failure to vaccinate children against this and other dangerous diseases like measles, mumps and rubella.

Over the past decade and especially in the last five years, an increasing number of parents are choosing not to vaccinate their children. Although the reasons cited vary, most surveys on the topic have found that parents fears with respect to vaccine safety are driving decreasing vaccination rates. One of the most common reasons cited has been a fear that vaccines might cause autism in a child.

While the theory of there being a link between vaccines and autism has been debunked by large population-based studies worldwide, hundreds of websites continue to perpetuate this theory. An early settlement by some pharmaceutical companies in response to lawsuits by families with autistic chidlren, has been cited by some proponents of the theory that a link exists despite subsequent court rulings stating that the was no evidence of such an relationship.

Some popular celebrities have also claimed such a link on popular programs like the Oprah Winfrey Show despite statements by the US Center's for Disease Control and Prevention (CDC) and the World Health Organization (WHO) that strongly recommend vaccinating children and outline the severe risks associated with not vaccinating children.

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