July 19, 2012 -- Whooping cough cases could be headed toward a 50-year high in the United States, and the CDC says the nation is on track for record rates of the disease.
Twice as many cases have been reported so far this year as at the same point last year, a CDC official said today.
Nationwide, nearly 18,000 cases of whooping cough, or pertussis, and nine deaths have been reported in 2012, Anne Schuchat, MD, director of CDC's National Center for Immunization and Respiratory Diseases, told reporters.
"We would need to go back to 1959 to find as many cases reported by this time in the year," she said.
Whooping Cough Worst in Babies
More than 3,000 cases have been reported in Washington State alone, where health officials have declared a whooping cough epidemic.
Pregnant women and anyone else likely to come into contact with young babies are being urged to get booster shots to prevent whooping cough, even if they have been vaccinated in the past.
That's because babies are most likely to die or be hospitalized when they get the highly contagious bacterial disease, which is named for the characteristic cough that accompanies it.
All of the whooping cough fatalities that have occurred this year have been among babies who were too young to be fully vaccinated, Schuchat said.
For children, the whooping cough vaccine DTaP is given in five doses, with the starting dose recommended at 2 months of age and the last dose recommended between the ages of 4 and 6 years.
More than half of children diagnosed with whooping cough before their first birthday require hospitalization.
Compared to children who are fully vaccinated, unvaccinated children have eight times the risk for getting whooping cough, Schuchat said.
When vaccinated children do come down with the disease, they tend to have milder symptoms and are less likely to pass their infection onto others.
Vaccine Change May Be Factor in Rise
The reasons for the dramatic increase in whooping cough cases are not entirely clear, but Schuchat offered several possible explanations.
She said better diagnosis and reporting of whooping cough may be contributing to the increased numbers, along with the fact that the disease tends to peak and wane in cycles.
It does not appear that anti-vaccination sentiment among parents has contributed to either the national rise in cases or the Washington State epidemic, she says.
She added that the CDC is investigating whether the switch from whole-cell to acellular pertussis vaccine in 1997 may have contributed to the increase, especially among young teens.
The acellular vaccine is less likely to cause fever and injection site reactions, and it may carry a lower risk for a very rare but serious neurological complication. But there are also suggestions that its protection may not last as long as the whole-cell version of the vaccine.
Booster Vaccination Rates Low
Mary Selecky of the Washington State Department of Health said the 3,000 cases reported so far this year in the state is triple the number seen during all of 2011.
"For every case that we know about we suspect that there are many cases out there that we don't know about," she says.
Selecky reiterated Schuchat's call for pregnant women and anyone else who comes into contact with babies to be vaccinated.
A booster pertussis, tetanus, and diphtheria (Tdap) vaccine has been available since 2005, but only about 8% of adults have gotten it, Schuchat said.
The CDC recommends Tdap booster for adults aged 19-64 who have not received Tdap previously. Pregnant women should wait until after the 20th week of pregnancy or preferably in the third trimester. If not given during pregnancy, then the dose should be given as soon as possible after delivery.
"I know that we can do better than this and we need to do better," Schuchat said.