Flu recs redefine HCW protection

Droplet, airborne — or a new hybrid?

In a lingering legacy of the H1N1 pandemic, stronger protections are now advised for seasonal influenza than was the case prior to the emergence of the novel H1N1 strain. That distinctive status was recently highlighted in new influenza guidance in California.

When the Centers for Disease Control and Prevention issued updated guidelines for this year's seasonal influenza, which includes H1N1, it recommended surgical masks for health care workers performing routine patient care but retained the advice for health care workers to use N95 respirators when performing aerosol-generating procedures. It also emphasized vaccination and a comprehensive strategy to prevent transmission of influenza.

California public health authorities reviewed that guidance and decided to step it up a bit. The California Department of Public Health (CDPH) is suggesting that employers allow their employees to wear N95 respirators if they want more protection than provided by surgical masks.

California also will enforce the use of respiratory protection for aerosol-generating procedures under that state's Aerosol Transmissible Diseases standard, says Barbara Materna, PhD, CIH, chief of CDPH's occupational health branch. Employers must list the exposure-prone procedures that occur at their hospital in their ATD exposure control plan.

"The respiratory protection is required no matter the immunization status," notes Deborah Gold, MPH, CIH, senior safety engineer in the research and standards health unit at Cal-OSHA in Oakland. After all, employers may not know whether a particular employee has been vaccinated or is exempt due to medical contraindications, and the flu vaccine is not 100% effective, she notes.

"We wanted to acknowledge...that people doing patient care are still going to be at some risk of exposure," says Materna. "If it's not appropriate for them to have the vaccine or the vaccine isn't 100% effective at providing immunity, they're going to be at some risk."

What about meningitis?

The California interpretation raises a new question: Will the changes related to influenza lead to a new approach to other droplet-spread diseases?

"This is the first time that a disease currently [designated for] droplet precautions has a requirement for respiratory protection for aerosol-generating procedures," says Materna. "We raise a question as to whether this would be required for other [diseases considered to be spread by droplets, such as meningitis]."

That concern was highlighted in a recent case of N. meningitidis transmission from an undiagnosed patient to a first responder and a respiratory therapist. Cal-OSHA cited Alta Bates Summit Medical Center in Oakland, CA, for failing to conduct a prompt exposure analysis or to readily offer prophylaxis after the meningitis case was identified.

The ER physician who performed suctioning and intubation on the patient and the respiratory therapist who assisted were not wearing a surgical mask or respirator. The respiratory therapist later developed meningitis and was hospitalized for 11 days. The physician was offered post-exposure prophylaxis eight days after the exposure.1

In fact, of 10 workers who had close contact with the patient, only four wore respirators — two firefighters and two paramedics. Only one of the five health care workers who assisted in care of the patient in the ER wore a surgical mask, and none wore a respirator. At the time, respirators were recommended for health care workers caring for patients with suspected pandemic H1N1 — and required by California's ATD standard.

The guidelines are clear for airborne infectious diseases such as tuberculosis. Health care workers must wear respirators and patients should be in airborne isolation rooms. CDC recommends droplet precautions — including use of a surgical mask by health care workers in close patient contact — for diseases "spread through close respiratory or mucous membrane contact with respiratory secretions" such as pertussis, N. meningitidis, and influenza.2

Can droplets become infectious aerosolized particles? Materna asserts that recent research "does support the fact that when people cough or sneeze they're emitting particles that can be inhaled." In its guidance, CDC acknowledges the potential for some airborne spread of influenza: "Airborne transmission via small particle aerosols in the vicinity of the infectious individual may also occur; however, the relative contribution of the different modes of influenza transmission is unclear."

Aerosol-generating procedures may increase the risk, even from droplet-borne pathogens, says Materna. While the current CDC guidelines recommend respirators only for health care workers caring for patients with tuberculosis, SARS and "avian or pandemic influenza viruses," the recent CDC and California guidance suggest that the protections may be expanded.


  1. Materna B, Harriman K, Rosenberg J, et al. Occupational transmission of Neisseria meningitidis – California, 2009. MMWR 2010;59:1480-1483.
  2. Siegel JD, Rhinehart E, Jackson M, Chiarello L, and the Healthcare Infection Control Practices Advisory Committee, 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings. Available at www.cdc.gov/hicpac/pdf/isolation/Isolation2007.pdf.