By Margarita Nahapetyan
Children whose parents do not want to immunize them are 23 times more likely to develop the whooping cough, or pertussis, compared to those kids who have all their vaccinations done on time, U.S. researchers reported last week.
In contrast, only one in 500 children who received their vaccination shots, developed whooping cough in the study by Kaiser Permanente Colorado's Institute for Health Research. The investigators said that their study, funded by government, appears to be the first to use medical records in order to confirm which kids received vaccinations and which ones did not -- and the subsequent rates of the whooping cough disease.
The experts said that while most parents have their kids vaccinated, leading to significant decrease in some serious childhood illnesses, a number of American families who reject immunizations, appears to be dramatically increasing. Pertussis, which features uncontrollable deep coughing, is fatal in a rare cases, but infants are the ones who are the most vulnerable and accounted for most of the 140 U.S. lethal outcomes from whooping cough between 2000 and 2005, said Dr. Jason Glanz, PhD., a senior epidemiologist at Kaiser Permanente's Institute for Health Research, who worked on the study. From the data available, it was impossible for the researchers to determine why parents are choosing to refuse the shots. The study also did not evaluate the side effects of vaccines.
The investigators based their conclusions on the analysis of records of 751 children with the ages between 2 months and 18 years. All the children were enrolled in the Kaiser Permanente Colorado health plan from 1996 to 2007. Throughout the period of the study, researchers identified 156 cases of laboratory-confirmed whooping cough. They compared these children to 595 other kids who did not develop the disease.
The results revealed that children of parents who refused to have their children immunized, were 23 times more likely to get the infection, compared to children who received the vaccine. What is more, another analysis of 27,748 young children between the ages of 2 and 20 months, showed that with 31 laboratory-confirmed cases of whooping coughing, there was a similar increase in the risk of developing the disease among kids of parents who refused to give their offspring the pertussis vaccine. Overall, between 11 and 12 per cent of pertussis cases in the total population were attributable to families' rejection of immunizations.
Researchers say that the reason why many families these days refuse vaccinations is that many of the vaccine-preventable diseases, such as whooping cough, smallpox, and polio, have become very rare. Parental concern, the experts explain, "seems to have shifted from preventing disease transmission to vaccine safety." "Now parents are no longer worried about the diseases themselves, as far as their children getting sick. They are more worried about vaccine safety," the researchers wrote. They also noted that some families are sure that vaccines 'overload' children's immune systems and result in chronic illnesses.
Another common belief is that there is a link between immunizations and autism. And in spite of the fact that no vaccine-autism connection has been proven yet, fears of developing autism after vaccination prompts many families to refuse some or all of the recommended immunizations for their children. Also, according to scientists, some individuals believe that their children are at low risk for getting an infection and that many vaccine-preventable diseases are not serious enough.
Researchers stress out that the findings of this new study are very important for parents who cite low risk of infection as a reason to choose fewer vaccinations or reject them completely, and for scientists as well, who are worried that decreased vaccination rates could result in more disease outbreaks across the country.
The findings will appear in the June 2009 issue of the journal Pediatrics, the journal of the American Academy of Pediatrics. The National Institute of Allergy and Infectious Diseases funded the study.