Pregnant Women to Get Pertussis Vaccine

June 23, 2011 -- To halt a spike in whooping cough cases and deaths in infants, pregnant women now are advised to get a booster shot of the pertussis vaccine in their late second or third trimester.

Vaccination against whooping cough -- pertussis -- can't start before age 2 months. But the disease is particularly deadly for unprotected infants. Of the 194 U.S. pertussis deaths from 2000 to 2009, 152 were in infants ages 1 month or less. Twenty-three deaths were in infants ages 2 to 3 months.

Doctors have been fighting recent outbreaks of whooping cough by giving the Tdap booster vaccine to women as soon as they give birth -- and also vaccinating everyone else who comes into contact with an infant. The idea, called "cocooning," is a good one. But in the real world, it's been nearly impossible to vaccinate most fathers -- and even harder to find and vaccinate grandparents, siblings, and caretakers.

"Is cocooning working? No, not at the national level," CDC researcher Jennifer Liang, DVM, told the CDC's Advisory Committee on Immunization Practices (ACIP) at yesterday's meeting. "We've had very little success vaccinating fathers and other family members."

"We need a new strategy," said ACIP working group chairman Mark Sawyer, MD, professor of pediatrics at the University of California, San Diego.

The new strategy: Give the Tdap booster vaccine to women in the late stages of pregnancy.

"It's a twofer," said ACIP chairwoman Carol Baker, MD, professor of pediatrics at Baylor College of Medicine, Houston. "By vaccinating in the late second or third trimester, you protect the mother and you protect the infant."

That's because the developing fetus gets a protective dose of its mother's antibodies. This protection can help bridge the gap between birth and the infant's own vaccination.

By a 14-1 vote, the ACIP recommended this plan. Women now will be given a booster dose of Tdap after their 20th week of pregnancy.

What about cocooning?

"We would never not recommend cocooning, but it is an insufficient national strategy to prevent pertussis mortality and morbidity," Liang said.

The Tdap booster vaccine is meant for teens and adults. Those who have already had their booster shot do not need another. But for those who aren't sure, a second booster is safe.