Infected HCWs shunned protective measures

Few H1N1 infected wore N95s, goggles, gowns

In the H1N1 influenza A pandemic, many infected health care workers failed to wear personal protective equipment. They became sick after caring for infected patients. In addition, they were infected after socializing with co-workers who came to work sick.

The bottom line: Health care workers need to improve their adherence to infection control precautions and they need work policies that encourage them to stay home when sick. Those are findings from analyses of cases in which health care workers acquired H1N1 in the early weeks of the pandemic.

From May 4 to June 1, 2009, the Centers for Disease Control and Prevention received 81 reports of health care workers with confirmed or probable pandemic H1N1 in 25 states. Two were hospitalized, including one health care worker with other underlying medical conditions. On average, the ill health care workers missed a week of work.

Half of the cases involved likely transmission in the health care setting, according to detailed information on 70 of the cases. About two-thirds of those occurred in inpatient care or an emergency room. In 20% of cases, there was no known exposure, either in the hospital or in the community.1

"One commonality we saw is that uniformly people who acquired H1N1 infection were not wearing respiratory protection of any sort when caring for patients," says Matthew Wise, PhD, epidemiologist with CDC's Division of Healthcare Quality Promotion and lead author. "This really points to a need for a comprehensive approach to infection control in these settings. We're not going to be able to promptly identify every patient who walks through the door."

A Health Hazard Evaluation of four hospitals affiliated with the University of Utah School of Medicine in Salt Lake City found similar gaps in the use of personal protective equipment.2 In part, that might have been because residents rotated among hospitals with different policies, says Marie A. de Perio, MD, medical officer in the Hazard Evaluations and Technical Assistance Branch for the National Institute for Occupational Safety and Health in Cincinnati and co-author of the Health Hazard Evaluation.

"The four medical centers all had four different recommendations for appropriate PPE when taking care of flu patients. That caused a lot of confusion among the house staff," she says.

Medical residents were most likely to report that they used PPE if they were present during aerosol-generating procedures or in the Intensive Care Unit. "That suggests to us that emphasis on PPE was strong in these high-exposure settings," she says.

Rare use of respirators, goggles

The spotty use of infection control precautions is striking, particularly considering that H1N1 was still emerging in the spring of 2009.

In 20 cases of probable or possible patient-to-health care worker transmission reported to CDC, less than half of the health care workers (9, or 45%) reported wearing gloves most or all of the time. Only two reported wearing respirators always or most of the time, and only five reported wearing a surgical mask always or most of the time.

Goggle or face shield use was virtually non-existent, although CDC had recommended eye protection (as well as respiratory protection, contact and standard precautions) when caring for pandemic H1N1 patients. Sixteen, or 89%, reported that they never used eye protection.

CDC's infection control guidelines recommend "protection of the eyes, nose and mouth by using a mask and goggles or face shield alone" when caring for a patient with a respiratory illness in which there is a risk of a splash or spray of respiratory secretions or bodily fluids.3

The findings were similar in the Utah evaluation. About two-thirds of the physicians were considered to have "low adherence" to protections based on their reports of PPE use.

Why didn't the physicians wear protective equipment? More than half of them (55%) said they didn't know the patient had pandemic H1N1 or an influenza-like illness. Lack of availability was identified as a common reason, as well, in the Utah survey.

In fact, even in those early weeks of the pandemic, three of the four hospitals reported having supply shortages of N95s and facing high prices to obtain more N95s, powered-air purifying respirators, or fit-testing kits.

Co-workers infected HCWs

Personal protective equipment wasn't the only problem. Health care workers faced an exposure risk from co-workers who came to work sick.

"That was a relatively common route of transmission among health care workers who were infected," says Wise.

He notes that about 20% of health care workers who became infected with H1N1 were non-clinical personnel — a receptionist in an outpatient clinic, a pharmacy technician, and a front office manager, for example.

"Those people didn't [seem to be] infected by contact with patients, but they were infected by ill health care workers," he says.

In the Utah evaluation, about three-quarters (77%) of physicians with influenza-like illness reported working while ill, and about half (52%) of all physicians surveyed reported having contact with a co-worker who was ill.

In dramatic evidence of the potential for transmission, a cluster of eight cases of influenza-like illness occurred among the residents and fellows within 48 and 96 hours of a resident dinner. Six of them had attended the dinner.

De Perio suggests that programs should be clear about how absences will be handled so that residents don't feel pressured to come into work because they don't want to burden their colleagues.


1. Wise ME, de Perio M, Halpin J, et al. Transmission of pandemic (H1N1) 2009 influenza to healthcare personnel in the United States. Clin Infect Dis 2011;52:S198–S204.

2. de Perio M, Brueck SE, and Mueller CA. Evaluation of 2009 pandemic influenza A (H1N1) virus exposure among internal medicine housestaff and fellows. Health Hazard Evaluation Report (HETA 2009-0206-3117). Available at Accessed on Dec. 14, 2010.

3. Siegel JD, Rhinehart E, Jackson M, et al. CDC Healthcare Infection Control Practices Advisory Committee. 2007 Guideline for isolation precautions: Preventing transmission of infectious agents in healthcare settings. Available at Accessed on Dec. 14, 2010.