CDC Updates Recommendations for Protecting Clinicians From Influenza

As new data about influenza transmission and concerns about potential shortages of some protective equipment have emerged, the US Centers for Disease Control and Prevention (CDC) has updated its guideline to help protect clinicians from infection with the 2009 influenza A(H1N1) virus.

Among the changes are more detailed strategies for reducing clinician exposure to influenza in hospitals, a reduction in the amount of time clinicians are advised to wait to return to work after an influenzalike illness, and strategies for stretching the supply of N95 respirators in case of shortages (http://www.cdc.gov/h1n1flu/guidelines_infection_control.htm). The changes come on the heels of data published in this issue of JAMA and released online on October 1 that suggest surgical masks may provide as much protection as the respirators (Loeb et al. JAMA. 2009;302[17]:1865-1871).

An Institute of Medicine (IOM) Committee in September recommended that health care workers use fit-tested N95 respirators rather than surgical masks for protection against 2009 influenza A(H1N1) (http://www.nap.edu/catalog.php?record_id=12748). Such masks are substantially more expensive and less readily available than surgical masks. The committee was instructed not to take into account potential supply issues. But if hospitals are faced with a large influx of patients infected with the virus, supplies could fall short.

However, the data reported by Loeb et al suggest that during routine clinical care of patients with influenzalike illness, cheaper and more readily available surgical masks might provide equivalent protection. The trial included 446 nurses working at 8 Ontario hospitals who were randomly assigned to wear either a surgical mask or fitted N95 respirator while caring for patients with fever and respiratory symptoms during the spring of 2009. The study's results suggest that larger droplets that can be filtered out by surgical masks may be driving infection of clinicians during routine care, explained Mark Loeb, MD, of McMaster University in Hamilton, Ontario, Canada, and lead author of the study. He cautioned that more research is necessary, however, and emphasized that clinicians should continue to wear N95 respirators for procedures that pose a higher risk of transmission, such as intubating a patient.

Kenneth I. Shine, MD, chair of the IOM committee, said during an interview in mid-October that the committee was aware of the abstract for the study by Loeb et al but chose to exclude it and other then-unpublished studies from its review. Because the IOM committee was dissolved after issuing its report, it cannot change its conclusion, but Shine said the committee recognizes the study as an important contribution to the evidence base and encourages further research.

The new CDC recommendations do take into account such emerging data and offer a variety of strategies hospitals can use to prevent infection among clinicians during the flu season. For example, the agency suggests that hospitals use a variety of administrative policies, physical barriers, and vaccination to protect health workers. If supplies of the preferred fit-tested N95 respirators run low, the agency suggests considering strategies such as training personnel in extended use or reuse of respirators (http://www.cdc.gov/h1n1flu/guidelines_infection_control_qa.htm). Another potential strategy suggested that, in certain circumstances, N95 respirators be reserved for the highest-risk care and for clinicians who are at greater risk of complications from influenza. Other clinicians who are performing lower-risk procedures on potentially infected patients and who are themselves at low risk of complications from infection would use surgical masks.

The CDC also said that a clinician who has had an influenzalike illness may return to work 24 hours after his or her fever resolves without the use of fever reducers instead of the 7 days previously suggested by the agency.