October 12, 2009

‘Mask debate’ diverts from flu-preventive measures that work

Infection control experts at Johns Hopkins and the U.S. Centers for Disease Control and Prevention report that a contentious debate in the medical community over what type of protective masks health workers should wear to prevent the spread of H1N1 and other flu viruses is dangerously distracting the health care community from focusing on simple prevention measures that are clearly known to work.

In an editorial published Oct. 1 in the Journal of the American Medical Association, Trish Perl and Arjun Srinivasan say that findings of a new study comparing the value of two types of medical masks are likely to ignite still more debate at a time when more emphasis should be placed on vaccination, rigorous hand washing and other proven prevention measures.

The mask study, conducted by a team of Canadian researchers, found that nurses who wore high-tech N95 masks were infected by influenza only slightly less often than those who wore common surgical masks, Perl and Srinivasan say.

Perl, chief epidemiologist at The Johns Hopkins Hospital, says that the release of the mask study, to be published in an upcoming issue of JAMA, will further distract attention from other important prevention measures.

“Unfortunately, this intense discussion over respiratory protection has distracted attention from the critical importance of implementing other strategies known to prevent the transmission of influenza in health care settings,” Perl and Srinivasan write in JAMA.

The authors say that prevention measures are even more pressing in health care settings today, given the re-emergence of the H1N1 influenza pandemic, which is widespread in much of the United States. A vaccine for H1N1 is expected to be publicly available in mid-October.

The chief prevention measure that should be employed more widely among health care personnel is flu vaccination, Perl and Srinivasan note in their editorial. Only about 45 percent of health care workers get a flu shot each year, the two experts say, citing a 2008 CDC study.

Annual flu vaccination of health care workers “has been shown to protect both patients and health care personnel, decrease patient mortality and minimize worker absenteeism,” the authors write.

Masking plays a role, the authors say, but a diverse approach—using measures such as keeping sick visitors from hospitals, rapidly moving patients with respiratory illness and high fever into isolation areas and developing programs to encourage cough etiquette and regular hand washing—is better.

Health care workers’ “adherence with hand hygiene is also far from ideal,” note the authors. In addition, health care workers commonly work despite having a respiratory illness, thereby putting patients and co-workers at risk. “Hence, a change in culture is needed; personnel must stay home when they are ill, and employers must penalize them when they do [come to work sick],” they add.

The authors conclude that while more research and discussion are needed about which type of mask health care workers should wear when near sick patients, that issue should not “excuse anyone from failing to implement other measures that are known to protect patients and [health care personnel] from influenza.”