Plan expert: CDC made 'serious mistake' on N95s

'What good is a guideline that can't be followed?'

The Centers for Disease Control and Prevention made "a serious mistake" in holding fast to a recommendation that health care workers wear N95s or comparable respirators during the H1N1 influenza A pandemic, a national pandemic planner says.

Eric Toner"That was a huge problem," says Eric Toner, MD, a pandemic planning expert and a senior associate with the Center for Biosecurity at the University of Pittsburgh Medical Center. "I think it was a serious mistake to hold health facilities to that guideline because it was never practical."

When the pandemic began in early spring 2009, the CDC viewed the novel virus with an appropriate abundance of caution and recommended N95 respirators, a step beyond surgical masks long used for seasonal flu. Eventually, the Occupational Safety and Health Administration (OSHA) stepped in to enforce the guideline, though infection preventionists already were arguing that surgical masks normally used for flu were sufficient and much more practical for most patient encounters. There also was a problem for even the most well intentioned: supplies.

"There were not enough — and still are not enough — N95 respirators to be used in the way that the guidance recommended," Toner says. "There was no opportunity for hospitals to buy enough N95s to follow the guidance. So even if they wanted to [follow the guideline] there was no way to do it. The CDC made a judgment that N95s were the highest degree of protection. I wouldn't necessarily argue with that, but what good is making a guideline that can't be followed?"

Data are in dispute

The data are in dispute. A recently published randomized trial showed that medical masks were just as effective as respirators in preventing flu infection.1 That was a serologic study involving blood draws, meaning the transmission could have occurred in the community in the absence of any respiratory protection. However, because the trial was randomized any differences in the groups can be linked to the intervention (respirator vs. mask). Nevertheless, occupational health experts can cite a wealth of research from laboratory trials showing fit-tested N95 masks are superior to surgical masks. The CDC recommended the higher level of protection for the novel virus, but there was another problem — compliance.

"It is well known that N95s are difficult to use for long periods of time and so compliance tends to be pretty poor," Toner says. "There's a lot of conflicting evidence as to whether or not they are really even necessary — [particularly] in this pandemic with this virus. I think it would be different if we were dealing with a more lethal virus, but we weren't."

At one point, the message became profoundly mixed, as the infectious disease community was reassuring people that H1N1 was transmitting like a normal influenza virus and public health officials were recommending respiratory protection in health care beyond levels used in any prior flu season.

"It was a contradiction," Toner says.

Moreover, IPs say the mandate that health care workers don N95 respirators to treat known or suspect H1N1 influenza A patients undermined the medical response, in part because it delayed discharge of H1N1 patients to facilities that didn't have the gear to comply. "The current recommendation [for N95] respirators is based on the unique conditions associated with the current pandemic, including low levels of population immunity to 2009 H1N1 influenza, availability of vaccination programs well after the start of the pandemic, susceptibility to infection of those in the age range of health care personnel, increased risk for complications of influenza in some health care personnel (e.g., pregnant women), and the potential for health care personnel to be exposed to 2009 H1N1 influenza patients because of their occupation," the CDC said in a statement.

The CDC was under considerable pressure from health care unions and worker safety advocates since at least four nurses nationally have reportedly died of complications related to H1N1. What is not known is whether the infections were acquired in the community or occupationally, and if the latter, whether respiratory protection levels were a contributing factor.

The respirator-mask situation escalated into an appeal to the highest office in the land, as the nation's leading infectious disease associations urged President Obama to halt federal enforcement of the mandate. However, there was no response from the executive office to the letter from the Association for Professionals in Infection Control and Epidemiology, the Society for Healthcare Epidemiology of America (SHEA), and the Infectious Diseases Society of America, says Neil Fishman, MD, president-elect of SHEA.

Politics superseded science

"I think it was clearly an instance where politics superseded the science," says Fishman, director of the department of Healthcare Epidemiology and Infection Control at the University of Pennsylvania Health System in Philadelphia. "That whole issue took a lot of energy and resources that could have been better applied elsewhere. My hope going forward is that the science has evolved adequately through the experience of this pandemic to demonstrate that medical masks are sufficient protection for influenza. I really hope that we don't see a move to make N95s the norm for influenza. That is unnecessary and would have unintended consequences."

However, Fishman says he would support N95 use for health care workers in the face of a more transmissible virus such as severe acute respiratory syndrome (SARS).

"I would be screaming out loud that we need to make sure everybody is using N95s," he says. "For influenza — regardless of the severity of the disease or the virulence of the virus — I'm confident that the science demonstrates medical masks are adequate."

In the aftermath of the H1N1 pandemic, IPs and clinical researchers need to make the scientific case that N95s are not a good option for pandemic influenza, says Ruth Carrico, RN, PhD, RN, CIC, a veteran IP and assistant professor of health promotion and behavioral sciences at the University of Louisville (KY).

"We on the clinical side have not done a good job of getting our results out into the medical literature," she says. "There are a lot of data that have been done in controlled settings by NIOSH and OSHA, but we haven't had that translated into what it means on the clinical side. So, we are partly responsible for getting ourselves into this mess."

That said, the whole concept of occupational and community illness needs to be clarified, she says. "We need to decide what this means in terms of infectious diseases," she says. "How do we carve away all the other confounders, like coming into contact [with disease] outside the workplace? We need to have a better understanding and people need to be willing to budge. This is what we call a donkey argument. Both sides are sitting down. Where is the middle ground in all of this — something that makes sense and allows you to do your job."


  1. Loeb M, Dafoe N, Mahony J, et al. Surgical mask vs. N95 respirator for preventing influenza among health care workers: A randomized trial. JAMA 2009; 302(17):1,865-1,871.