Recent study revealed that children who are not immunized against whooping cough have 23 times higher risk of getting the infection as compared to immunized children.

Researchers reviewed the health records of Kaiser Permanente Colorado members aged 2 months to 18 years between 1996 and 2007. Study revealed that cases of whooping cough have increased. Researchers also found that number of parents refusing to have their children vaccinated is increasing in the United States.

Lead author Jason Glanz, a senior scientist at Kaiser Permanente's Institute for Health Research, said: "This study helps dispel one of the commonly held beliefs among vaccine-refusing parents: that their children are not at risk for vaccine preventable diseases."

"It also shows that the decision to refuse immunizations could have important ramifications for the health of the entire community. Based on our analysis, we found that one in 10 additional whooping cough infections could have been prevented by immunization."