Infant pertussis outbreak emphasizes need to vaccinate health care workers

The cases of 11 infants who contracted pertussis from a health care worker have renewed calls to get adolescents and adults vaccinated against the infection, particularly if they work in a hospital or other medical setting.

"We think it's very important that people do everything to prevent pertussis in infants, and this means immunizing teens, adults, parents of infants and people who are taking care of infants. It means immunizing health care workers," said Don Murphey, MD, lead author of the paper outlining the incident published in the June 6 Morbidity and Mortality Weekly Report. He is also the medical director of occupational health at Cook Children's Medical Center in Ft. Worth, Texas. The infants were infected at another hospital in the community.

The outbreak occurred a year before the Food and Drug Administration's 2005 approval of Tdap -- the vaccine that includes the pertussis immunization -- for adults and adolescents. This step was followed by recommendations from the Advisory Committee on Immunization Practices urging that all adolescents and adults receive the preventive, with those working for a medical institution viewed as especially high-priority targets. The American Medical Association encourages health care workers to be immunized for their own protection and to reduce transmission to others. But most experts suspect that many health care professionals remain unimmunized and that the risk that outbreaks will continue remains high.

"Patients should have the right and every expectation that they're not going to get diseases that they didn't have when they went into the exam room or hospital," said Greg Poland, MD, professor of medicine and director of the vaccine research group at Mayo Clinic in Rochester, Minn.

No data have been collected on how many health care workers have received the Tdap vaccine, although numbers pertaining to the general adult population are not encouraging. According to statistics released in January from the Centers for Disease Control and Prevention's National Immunization Survey, 2.1% of 18- to 64-year-olds had received it. Also, a study published in the November 2007 issue of the journal Infection Control and Hospital Epidemiology found that 87% of health care workers were not planning to receive it.

Experts are concerned because health care workers are more likely to get pertussis in the course of their job. They also are more likely to transmit it to those most likely to experience complications.

"[Pertussis] is clearly a hundred-day cough in adolescents and adults," said Grace Lee, MD, MPH, assistant professor of pediatric infectious diseases at Harvard Medical School in Boston. "Vaccination protects them and their families. It protects the patients." She has published several papers on the cost effectiveness of this vaccine.

Some medical institutions are piggybacking pertussis vaccination efforts onto those for influenza. In some ways, pertussis vaccination is easier because it doesn't have to be given annually or during a narrow window in the fall and winter like flu vaccine, but motivating health care workers to get the shot is challenging. It's fairly new -- some people are not aware of it or that protection from childhood pertussis immunization likely has waned. Also, even though cases of pertussis have increased among adults, it's still viewed as a childhood disease. So the vaccine may not be viewed as vital for adults.

"This does require a whole new kind of paradigm, and we need to educate both the professional staff and others in the hospital about why we're talking about whooping cough," said William Schaffner, MD, president-elect of the National Foundation for Infectious Diseases and chair of the Dept. of Preventive Medicine at Vanderbilt University School of Medicine in Nashville, Tenn.

The price of the vaccine also may be a barrier, although studies have shown that vaccination saves money by reducing disruption and the need for prophylactic antibiotics caused by outbreaks.