Whooping cough vaccine not as powerful as thought

Whooping cough vaccine not as powerful as thought

 

…Of the 18 students in the recent Cobb cluster, 17 were properly immunized with five doses of DTaP vaccine, which protects against diphtheria, tetanus and pertussis, health officials said.

 

…But scientists are struggling to understand why reports of pertussis cases have risen dramatically since the 1980s. It may reflect more testing or diagnosis; it may reflect the cyclical nature of the disease. It’s even unclear how often clusters like the one in Cobb occur.

 

About 10,000 cases and 20 infant deaths were reported in the United States last year, but some studies have suggested the number of people sickened each year may be closer to 300,000, CDC officials said.

Experts believe the disease is underdiagnosed and underreported in vaccinated school-age children and adults who often have milder symptoms and whose childhood shots have worn off. They believe that adolescents and adults are spreading the disease to vulnerable infants and children.

 

…While no vaccine is 100 percent effective, some parents are surprised and angry that a vaccine they trusted is failing to protect some children. And officials with the Georgia Division of Public Health said too many local doctors are not aware the disease is circulating in the community and can infect fully vaccinated children.

 

Nationally, school-age children diagnosed with the disease are generally teenagers, which is what prompted a CDC advisory panel in 2005 to recommend an additional pertussis booster shot at age 11 or 12.

To try to determine the magnitude of the problem at the four Cobb schools, last month CDC and local health officials gave voluntary pertussis tests to 108 children and staff who were currently coughing, and 22 of them showed evidence of recent infection, said Julie Gabel, a state health department epidemiologist.

Despite the study’s test results, some doctors refused to believe parents when they said that their children had pertussis. “More than one said to the parent: ‘Well, your child couldn’t have had pertussis, your child’s been vaccinated,” Gabel said, adding that the department is working to educate physicians.

At the four schools, health officials think the outbreaks are over or winding down. But whooping cough continues to be reported elsewhere. Georgia health officials aren’t aware of any other current whooping cough clusters.

…“The real issue is what the rate of vaccine failure is,” said Orenstein, a former CDC official who recently became deputy director for vaccine preventable diseases at the Gates Foundation in Seattle…

 

PERTUSSIS CASES

U.S.

2009* 1,699

2008 10,007

2007 10,454

2006 15,631

2005 25,617

2004 25,827

2003 11,647

 

* Year so far

Source: CDC

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