MONDAY, March 11 (HealthDay News) -- Despite high levels of vaccination, the rate of whooping cough in the United States is at its highest level in decades, and one reason may be that immunity from the vaccine diminishes each year after the fifth dose is given.
New research from the U.S. Centers for Disease Control and Prevention (CDC) confirms what other recent studies have found: protection against whooping cough wanes significantly between the fifth dose of the vaccine -- given sometime during the 4- to 6-year-old age range -- and the adolescent booster vaccine given at 11 or 12.
"This study provides fairly strong evidence that the trends we're seeing are real -- and a couple of other studies with similar findings have recently come out," said study lead author Sara Tartof, who was at the CDC at the time of the study and is now a researcher at Kaiser Permanente in Los Angeles.
Nonetheless, "the vaccine is still a great tool," she said. "Kids who are fully vaccinated who get whooping cough have a much milder disease than those who aren't vaccinated. Vaccines are still the best protection against disease, and the incidence of whooping cough is low."
Whooping cough, which is also called pertussis, is a highly contagious bacterial disease that attacks the respiratory system. In 2012, the United States had the highest number of whooping cough cases since 1959, according to the CDC. During 2012, the CDC received reports of 41,000 cases and 18 deaths, with most of the deaths occurring in infants.
The whooping cough vaccine also includes immunizations for diphtheria and tetanus. It's given in a five-dose series at 2, 4 and 6 months; at 15 to 18 months; and between 4 and 6 years, according to the CDC. An adolescent booster is recommended between age 11 and 12.
The current study, published online March 11 in the journal Pediatrics, looked at children bo
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