A recent study suggests that whooping cough vaccine’s protective effect eventually fades away as years go by. Researchers found that in the year following vaccination the vaccine has a protective role only in 69 percent of middle-schoolers.
After four years since immunization the situation is a lot grimmer – the vaccine is still doing its job in just 9 percent of vaccinated kids. The study was published Feb 5 in the medical journal Pediatrics.
The study results may point to an explanation to why the U.S. has been plagued by so many whooping cough outbreaks in recent years despite tremendous vaccination efforts.
According to a 2012 report issued by the Centers for Disease Control and Prevention, more than 48,000 new cases were recorded in the U.S., which is higher than reports have suggested in 1955.
Currently, kids first receive the vaccine at kindergarten, while at the age of 11 or 12 immunization is repeated once more. CDC experts also recommend adults to renew their whooping cough vaccine until the age of 64.
Official reports show that immunization efforts paid off in the last century, as cases of whooping cough, or pertussis, plunged from over 227,000 in the late 1930s to fewer than 1,000 cases in the mid-1970s.
The type of vaccine was swapped with an improved version in the 1990s as population became concerned over the horrendous side effects of the earlier vaccine – seizures, uncontrollable crying bouts, fever, and limp muscles.
But Paul Offit of the Children’s Hospital of Philadelphia believes that the new vaccine dubbed DTaP has traded effectiveness for safety.
Nicola Klein, lead author of the latest study and head of the of Kaiser Permanente’s Vaccine Study Center, found that during the recent whooping cough outbreaks including those in California, most kids affected by the conditions had been immunized.
Researchers also found that kids aged 10 to 16 represented the group with the highest risk of contracting the infectious disease. Additionally, older kids and adults were at lower risk. Scientists believe that that may be because they had been immunized with several doses from the older vaccine.
Klein believes that we should expect for larger pertussis outbreaks in the coming years as the effect of the vaccine gradually fades away. Study authors think that a simple solution as repeating vaccination during an outbreak might just solve the problem.
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