Whooping cough cases expected to hit 10-year high

The national outbreak of pertussis, or whooping cough, is hitting Connecticut and has public health officials calling on residents to get vaccine boosters.

Last year, there were 68 reported cases of pertussis in the state. There have been 111 reports already this year, according to the state Department of Public Health. The disease has not caused any known deaths in Connecticut in recent years, said Kathy Kudish, DPH's vaccine preventable disease epidemiologist. Kudish expects cases to reach a 10-year high.

One culprit behind the increase is "waning immunity." People who received the standard series of pertussis vaccines in childhood are contracting the disease, often in adolescence.

The Centers for Disease Control recommends a pertussis booster, Tdap, for people age 11 and older to boost immunity. Last year, Connecticut began requiring the booster for children entering the seventh grade.

"It's really important that people who are expecting a child make sure that they've had the Tdap booster," said Kudish. "We really want to protect the most vulnerable, and that's infants up to 12 months." Anyone who has contact with an infant or is immune compromised should promptly get the vaccine, she added.

The state is encouraging other adults and parents of children 11 and older to talk with their primary care provider to find out if they have received the Tdap booster.  In October, pharmacists will be authorized to offer the Tdap booster to people 18 and older. (Editor's note: This corrects an earlier version of this article.)

Through mid-August, 22,000 cases of pertussis were reported across the United States, with 13 deaths, mostly among infants. There were 18,719 cases reported to the CDC for all of last year.

Most cases of pertussis are never reported, according to Kudish. The characteristic "whooping" sound of attempts to breathe between coughs does not necessarily occur in older patients. More accurate diagnostic tests for pertussis may be contributing to the uptick in reported cases, she said. Like many infectious diseases, pertussis is cyclical, with periodic increases in cases, said Kudish.

The waning immunity of DTaP, the standard childhood vaccine against pertussis since the 1990s, has provided fodder for people who oppose immunizations generally, said Amy Pisani, executive director of the Connecticut-based Every Child By Two, an organization that promotes vaccination. She called DTaP "not a perfect vaccine, (but) it's not a dangerous vaccine."

In the 1990s, DTaP, an acellular vaccine that contains only part of the bacterium that causes pertussis, replaced a whole cell vaccine that did confer longer immunity. The switch was made in part because of public fears about whole cell vaccines, Pisani said. The whole cell vaccine can cause side effects, such as fever. Some anti-vaccine advocates believed the shot caused epilepsy, though scientists generally dispute that claim.

This story was reported under a partnership with the Connecticut Health I-Team (www.c-hit.org).