Navigation Links
Whooping Cough Vaccine Less Effective Over Time: Study

By Serena Gordon
HealthDay Reporter

TUESDAY, Nov. 27 (HealthDay News) -- Vaccination does safeguard children against whooping cough, but its protective effect seems to lessen over time, new research finds.

The 2010 outbreak of whooping cough (pertussis) in California, which sickened more than 9,000 people and left 10 infants dead, prompted an examination of the current vaccine's effectiveness. That study concluded that the vaccine is effective but loses power over the years, leaving children 7 to 10 years old particularly susceptible.

"The pertussis vaccine is our best protection against disease," said the study's lead author, Lara Misegades, an epidemiologist at the U.S. Centers for Disease Control and Prevention in Atlanta. "We found that unvaccinated children were eight times more likely to be a pertussis case than vaccinated children. Parents should ensure children complete the childhood series and make sure your children get the adolescent booster too."

In the United States this year, more than 36,000 whooping cough cases have been reported, including 16 deaths -- most in infants younger than 3 months old, according to the CDC.

Because the vaccine's protective shield diminishes over time, health experts have suggested that the current vaccine dosing schedule may need reevaluation.

"We're continuing to evaluate the changing epidemiology [of pertussis], but it's too early to speculate if there's a need for an additional booster," Misegades said.

Results of the study appear in the Nov. 28 issue of the Journal of the American Medical Association.

The vaccine, commonly referred to as the DTaP vaccine, also includes immunizations for diphtheria and tetanus. It is given in a five-dose series at 2, 4 and 6 months; at 15 to 18 months; and between 4 and 6 years. An adolescent booster is recommended between age 11 and 12.

The current study was designed to evaluate how long it had been between the last DTaP vaccination and the development of pertussis in patients involved in the California outbreak, the state's largest in 60 years.

The study included data from 15 California counties with a high incidence of whooping cough cases. A total of 682 children aged 4 to 10 years who had pertussis were included, and for each of these children three kids of the same age from the same physician practice who did not have pertussis were selected for comparison.

The researchers found that, compared to the controls, children who had contracted whooping cough were 89 percent less likely to have received all five doses of the vaccine. Children with the disease were more likely to be unvaccinated compared to those without the disease -- 7.8 percent versus 0.9 percent, according to the study.

The researchers also found that the more time that had passed since vaccination, the less effective the vaccine appeared to be.

"Within the first few years, the vaccine's efficacy was around 98 percent," Misegades said. "Five or more years out, the vaccine effectiveness had dropped to about 71 percent."

Seven- to 10-year-old children had the highest incidence of disease, and incidence increased with age. About 3 percent of the cases occurred in 4-year-olds, while 31 percent of the cases were in 10-year-olds.

The current vaccine is an acellular vaccine, and it doesn't contain whole cells of the bacterium responsible for pertussis infections. The previous vaccine did contain whole cells of the bacterium, but was more likely to cause side effects, according to the study.

The switch to the acellular vaccine may partly explain the resurgence of pertussis, according to an accompanying journal editorial, but other factors may also be involved. Better diagnosis may also play a role, Dr. Eugene Shapiro, a professor of pediatrics and epidemiology at the Yale University School of Medicine, wrote in the editorial.

Dr. Kenneth Bromberg, director of the Vaccine Study Center at the Brooklyn Hospital Center in New York City, agreed that the whole-cell vaccine may have been more effective than the acellular vaccine, although he pointed out that the whole-cell vaccine sometimes had production issues and one batch of vaccine wasn't always as effective as another. And, he said, the components of that vaccine that may have increased effectiveness may be the very ones that also increased the risk of side effects.

The takeaway message for parents, Bromberg said, is that "the vaccine works. It's effective, so make sure everyone is appropriately vaccinated according to the current schedule."

"We'll have to wait for further study to [determine if the current dosing schedule needs change]," he said. "Parents should stay tuned as to whether we recommend additional vaccinations for pertussis."

More information

Learn more about pertussis vaccines from the U.S. Centers for Disease Control and Prevention.

SOURCES: Lara Misegades, Ph.D., M.S., epidemiologist, U.S. Centers for Disease Control and Prevention, Atlanta; Kenneth Bromberg, M.D., chairman, pediatrics, and director, Vaccine Study Center, Brooklyn Hospital Center, New York City; Nov. 28, 2012, Journal of the American Medical Association

Copyright©2012 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. What did we learn from the 2010 California whooping cough epidemic?
2. Whooping Cough Cases Reaching Record Highs: CDC
3. Is Improved Vaccine Causing Whooping Cough Outbreaks?
4. Whooping Cough Vaccine Protection Fades Over Time: Study
5. CDC Panel: All Pregnant Women Should Get Whooping Cough Shot
6. Honey a Sweet Treatment for Kids Night-Time Cough
7. Secondhand Smoke May Impair Childrens Cough Reflex
8. Chronic Cough Responds to Epilepsy Drug, Study Finds
9. Prenatal exposure to pesticide additive linked with childhood cough
10. Antibiotics Dont Ease Coughs in Kids With Common Cold: Study
11. Study Suggests Vaccine May Help Kids With Brain Cancer
Post Your Comments:
Related Image:
Whooping Cough Vaccine Less Effective Over Time: Study
(Date:11/25/2015)... ... 2015 , ... Beddit® has launched a new Android app for ... features a more intuitive SleepScore™ that rates sleep quality on a 100-point scale and ... created by a proprietary algorithm. Beddit analyzes the data to provide an easy to ...
(Date:11/25/2015)... (PRWEB) , ... November 25, 2015 , ... In an ... Resurrection Medical Center (RMC) in Chicago, IL, UV Angel is evaluating the efficacy of ... and surgical intensive care units (totaling 30 beds) from May 2014 through October 2015 ...
(Date:11/25/2015)... ... ... Today, Mothers Against Drunk Driving (MADD) learned that the number of ... time since 2011. In 2014, there were 9,967 fatalities involving an alcohol impaired driver, ... Traffic Safety Administration (NHTSA), 32,675 people were killed in traffic crashes in 2014. Drunk ...
(Date:11/25/2015)... Silver Spring, Md (PRWEB) , ... November 25, ... ... the Pulmonary Hypertension Association (PHA) announces the nation’s Periwinkle Pioneers, individuals and groups ... the history of this disease. The Periwinkle Pioneers, nominated by the public, will ...
(Date:11/25/2015)... , ... November 25, 2015 , ... ... announced that it has undertaken significant expansion of its current state of the ... is part of PharmaTech’s strategy to increase its manufacturing capacity as well as ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... , November 26, 2015 3D ... by 2022, according to a new report by Grand View ... Kidney Disease (CKD) which demands kidney transplantation is expected to ... cost effective substitute for organ transplantation. --> 3D ... by 2022, according to a new report by Grand View ...
(Date:11/26/2015)... November 26, 2015 ... the "2016 Future Horizons and Growth ... Testing Market: Supplier Shares, Country Segment Forecasts, ... their offering. --> ) ... "2016 Future Horizons and Growth Strategies in ...
(Date:11/26/2015)... November 26, 2015 ... adds "Global Repaglinide Industry ... Report on China Repaglinide Market, 2010-2019" ... data and information to its online ... . --> ...
Breaking Medicine Technology: