Ups and downs of whooping cough vaccine

The whooping cough epidemic in Washington State — as of Tuesday, there were 3,014 cases of the bacterial infection that causes cold-like symptoms and serious coughing fits in kids and adults, but can be fatal for babies — has fueled a new debate about the vaccines that once nearly wiped out this illness.  This week, the Centers for Disease Control and Prevention warned that the country is in for the worst year of whooping cough outbreaks since 1959.

Whooping cough’s comeback can’t be explained fully by the rising numbers of families that refuse vaccines for their children (and for parents, too), the CDC now says. It’s emerging that reformulated vaccines introduced in the 1990s aren’t as protective as older vaccines.  The older, “whole cell” DTwP vaccine (it protects against diphtheria, tetanus, and pertussis) — which contained entire, dead pertussis bacteria — was phased out in 1997 due to concerns about side effects. But the new vaccine, the acellular DTaP given to babies and kids up to age 7, seems to lose effectiveness — dropping to about 70 percent protection within five years according to the Washington State Department of Health. And a booster vaccine for teens and adults, called Tdap, also seems to weaken after a few years.

As a result, whooping cough numbers are slowly rising in kids after age 7 — spiking at age 10, then dropping off for a year or two when they receive the Tdap vaccine, then rising again among 13- and 14-year-olds. Older teens who received the older vaccine as little kids seem to have better protection, the CDC says.

Family decisions to decline vaccine are contributing to the increase, the CDC says. That’s especially true in Pennsylvania and a handful of other states that allow parents to say no for personal or philosophical reasons. All states allow religious and medical exemptions. But 50% of all whooping cough in the US this year come from six states (the others are Wisconsin, Washington, Texas, Arizona and Ohio) that offer a personal or philosophical exemption.  In the 2009-2010 school year, 3 percent of Pennsylvania kindergarteners had vaccine exemptions — including 1,777 for medical reasons and 2,924 for religious, personal or philosophical reasons. In New Jersey, 1 percent had exemptions (167 were medical, 905 were religious — personal or philosophical exemptions aren’t allowed); in Delaware, less than 1 percent of kindergarteners had exemptions for medical or religious reasons.)

Pertussis may also be on the rise due to better reporting or to changes in the bacteria itself. Taken together, the changes translate into two to three times more whooping cough in Pennsylvania this year compared to last year, three times more in New Jersey and a smaller increase in Delaware.           

The best way to protect your family, experts say, is still getting the vaccine. Vaccination lowers risk for infection, for passing pertussis along if you do get it, and for shorter, less severe symptoms. It’s also important to be aware of the symptoms. Here’s what health experts on the front lines in Washington State recommend:

For Infants and Children: In the U.S., the recommended pertussis vaccine for children is called DTaP. This is a safe and effective combination vaccine that protects children against three diseases: diphtheria, tetanus, and pertussis. For maximum protection against pertussis, children need five DTaP shots. The first three shots are given at 2, 4, and 6 months of age. The fourth shot is given at 15 through 18 months of age, and a fifth shot is given when a child enters school, at 4 through 6 years of age. If a 7-10 year old is not up-to-date with DTaP vaccines, a dose of Tdap should be given before the 11-12 year old checkup.

For Preteens and Teens: Vaccine protection for pertussis, tetanus, and diphtheria can decrease with time. Preteens going to the doctor for their regular check-up at age 11 or 12 years should get a booster vaccine, called Tdap. Teens and young adults who didn't get a booster of Tdap as a preteen should get one dose when they visit their health care provider.

For Pregnant Women: Pregnant women who have not been previously vaccinated with Tdap should get one dose of Tdap during the third trimester or late second trimester – or immediately postpartum, before leaving the hospital or birthing center. By getting Tdap during pregnancy, maternal pertussis antibodies transfer to the newborn, likely providing protection against pertussis in early life, before the baby starts getting DTaP vaccines. Tdap will also protect the mother at time of delivery, making her less likely to transmit pertussis to her infant.

For Adults: Adults 19 years of age and older who didn't get Tdap as a preteen or teen should get one dose of Tdap. Getting vaccinated with Tdap at least two weeks before coming into close contact with an infant is especially important for families with and caregivers of new infants. The easiest thing for adults to do is to get Tdap instead of their next regular tetanus booster — the Td shot that is recommended for adults every 10 years. The dose of Tdap can be given earlier than the 10-year mark, so it's a good idea for adults to talk to a health care provider about what's best for their specific situation.

Know the warning signs: Whooping cough typically starts with coldlike symptoms that can include a runny nose, congestion, fever, and a mild cough. Coughing may become so severe that it’s hard to take a breath — but babies may not even cough. The CDC advises parents to see a doctor if they or their children develop a prolonged or severe cough. Whooping cough is treated with antibiotics, the earlier the better.