CDC ponders change in H1N1 recommendations
Debate continues on flu transmission mode
Should health care workers wear respirators when caring for patients with novel H1N1? In mid-June, the Centers for Disease Control and Prevention was considering a shift from airborne precautions to droplet precautions, which would mean that health care workers would wear surgical masks when caring for patients. Respirators would still be recommended for aerosol-generating procedures.
By this summer, many states already were recommending surgical masks, and an advisory panel of experts questioned the need for respirators if the virus was no more virulent than seasonal influenza. "The initial approach was warranted before the transmission dynamics and severity were clearly known," says Lisa Maragakis, MD, MPH, associate hospital epidemiologist at The Johns Hopkins Hospital in Baltimore.
"The virus is like seasonal flu, and we should take the same precautions as with seasonal flu," says Maragakis, who is a liaison to the Healthcare Infection Control Practices Advisory Committee (HICPAC) for the Society of Healthcare Epidemiologists of America (SHEA).
However, health and safety directors of labor unions that represent millions of health care workers urged CDC to maintain a higher level of protection, particularly since experts acknowledge that the virus could change in its virulence if it re-emerges, as expected, this fall. Also, there is no pre-existing immunity to the virus among the general population, as there is for seasonal flu strains. (Flu experts say adults over the age of 60 may have some partial immunity from decades-old exposure to an H1N1 strain.)
"We believe the H1N1 outbreak is different from seasonal influenza," says Bill Kojola, an industrial hygienist with the AFL-CIO. "The two ought to be treated differently."
At press time for Hospital Employee Health, the CDC was holding to its recommendation that health care workers caring for H1N1 patients wear N95 respirators.
Questions about precautions
The response to novel H1N1 reveals continued contention about whether influenza is airborne or droplet-spread and whether respirators are necessary to protect health care workers.
Recent influenza research indicates that influenza particles remain airborne, but some infection control experts question whether those particles are infectious.
When making a decision about respiratory protection, it's important to know the infectious dose as well as the routes of transmission, says Roland BerryAnn, deputy director of National Personal Protective Technology Laboratory of the National Institute for Occupational Safety and Health, which is a part of CDC. That is particularly difficult to determine with a novel strain, he notes.
"It's not an exact science. People are trying to make the best decisions on the epidemiological evidence that they're gathering during the outbreak. [They're] trying to assess the protective recommendations to the hazard and continue to protect the workers," he says. "Thus far, we are still maintaining the aerosol precaution as well as the droplet precautions."
While there have been spot shortages of certain N95 models, BerryAnn says respirator manufacturers report that they will be able to meet their orders over the next six months. "There are no distribution or production problems to speak of to prevent the delivery of the equipment," he says.
Some health departments decided soon after the emergence of H1N1 to place less reliance on the N95 respirator. For example, Tennessee diverged from the CDC recommendations as of May 5, about 10 days after the first CDC Health Advisory.
The Tennessee recommendation for droplet precautions applied more broadly. At the time, CDC set a case definition of patients who had traveled to Mexico or U.S. locales that had confirmed cases. Yet epidemiological links were being lost so that cases emerged without a clear connection to Mexico or some other outbreak spot, says Marion Kainer, MD, MPH, medical epidemiologist for the Tennessee Department of Health.
"Tennessee recommended droplet precautions with every patient with febrile respiratory illness and respiratory protection for aerosol-generating procedures on patients with febrile respiratory illness," she says. "We wanted to emphasize administrative controls and a tiered approach. We felt that was protecting more health care workers."
However, as of mid-June, there still was a lot of uncertainty about the novel H1N1 - both in terms of its future patterns of transmission and virulence as well as the public health response to it.
"Pandemic planning is based on high virulence and limited resources," says Michael Bell, MD, associate director for infection control in CDC's Division of Healthcare Quality and Promotion. "We do have a set of [recommendations] for something that is very severe. We don't have a systematic way to step away from that."
Should health care workers wear respirators when caring for patients with novel H1N1? In mid-June, the Centers for Disease Control and Prevention was considering a shift from airborne precautions to droplet precautions, which would mean that health care workers would wear surgical masks when caring for patients. Respirators would still be recommended for aerosol-generating procedures.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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