What You Need to Know About Pertussis

Pertussis—known to most of us as whooping cough or "100-day cough"—is a highly contagious disease that starts with cold symptoms and progresses to coughing bouts severe enough to leave patients gasping for air. The United States is headed for the worst pertussis epidemic in 60 years, with more than 18,000 cases reported in 2012. What do you need to know to keep your family healthy?

“Pertussis can affect all ages,” said Yvonne Maldonado, MD, Packard Children's service chief of pediatric infectious disease. “It's transmitted by coughing and is very contagious.” The disease is caused by a bacterium, Bordetella pertussis, which produces many different toxins. These toxins stimulate the body's immune response, making our airways very inflamed and swollen.

Infants less than a year old, especially babies under six months of age, are most vulnerable to complications of pertussis, with about a dozen babies dying in the U.S. each year. Because babies have small airways, the swelling leaves little room for breathing. Babies with pertussis struggle to inhale, taking a big breath that produces the classic “whoop” sound. “They may have spells during which they stop breathing,” added Maldonado, “and can also develop secondary bacterial pneumonia.”

Antibiotics can eliminate the B. pertussis bacteria but they do not work against the toxins that cause airway swelling. This means babies may stay sick for weeks or months.

Vaccination for pertussis began in the 1950s; yet, as Maldonado explained, there is recent evidence that newer and safer vaccines may not provide long term immunity, leaving people who have not been recently vaccinated vulnerable to the disease. “That's why a booster shot is now recommended for everyone over age 10,” she said.

California has had less than 400 cases so far this year, a huge drop in the number of cases compared to 2010, when 9,000 people got sick and 10 infants died in California alone. Up to 80 percent of babies with pertussis get infected by someone in their household, such as a parent, grandparent or sibling. Significant measures at the state level helped reduce exposure to pertussis, including an effort to protect new babies who are too young to be vaccinated by “cocooning” – vaccinating all family members around that baby.

Infants should be vaccinated at 2, 4 and 6 months, with a booster shot at age 15-18 months and another at age 4-6 years. The pertussis vaccine is among those required for children to enter kindergarten in California. Starting in the 2012-13 school year, California law also requires children entering 7th grade to have a pertussis booster.

Adults of any age who have not had a booster shot since childhood should receive the vaccine, as should pregnant women in their third trimester. “We think the mother develops antibodies that cross the placenta to the baby, so her infant will be born with some protection,” said Maldonado, “Expectant dads and grandparents who will spend a lot of time around a newborn should get vaccinated, too.”

Ask your primary care physician or your child's pediatrician for information about receiving the vaccine. For local families that lack a health care provider, Santa Clara County provides information about obtaining low-cost pertussis vaccination for children at http://www.sccgov.org/sites/sccphd/en-us/Residents/IzClinic/Pages/TdapClinics.aspx.