Influenza Vaccine Mandate Math

Last week, I described five steps individual hospitals, systems and society should take when implementing compulsory influenza vaccination of healthcare workers. One component of many influenza vaccine policies is mandatory surgical masks for healthcare workers who refuse or otherwise cannot receive the vaccine. Does masking unvaccinated healthcare workers even make sense? Or rather, who is more likely to spread influenza in hospitals - an unmasked, vaccinated healthcare worker or an unvaccinated, masked healthcare worker? Let's look at the numbers.

Let's assume influenza vaccine is 50% effective. In 2014-15, overall effectiveness was 19% while in 2012-13 and 2013-14 it was 49% and 51%, respectively. I'll give the vaccine a mulligan last year since during the prior decade, vaccines were far more effective. Let's further assume with vaccine mandates, 90% of healthcare workers receive the vaccine and 10% do not.

If 90% receive a vaccine that is 50% effective, we will have 45% of healthcare workers in our hospital protected and 45% unprotected. The tricky thing is that we won't know who is protected or unprotected. And what if the 45% vaccinated but non-immune healthcare workers assume they are immune and work while sick? You can imagine them saying - "I'm sick, but it's not influenza because I was vaccinated, so I'll do my ICU shift." Any mandatory vaccination policy should consider that scenario or it's possible that the mandate could make hospitals less safe. But what of the 10% required to wear masks? I suspect they'd be more likely to stay home if sick, but even if they don't they'll be wearing a mask!

Finally, if I had a choice between being cared for by a vaccinated, unmasked healthcare worker or a masked, unvaccinated healthcare worker, I'd chose the mask. That is, until we implement influenza prevention bundles that focus on presenteeism.

Note: Mike wrote a fantastic quantitative post (in 2010!!) comparing a vaccine mandate to a presenteeism reduction policy. His conclusion: "Reducing presenteeism by 1 percentage point (from 70% to 69%) would have the same impact as increasing vaccination from 70% to 98%." It's too bad not many read the blog back in 2010...

Here come the maskers

Recently, the New York State Health Department mandated that all healthcare workers either be vaccinated against influenza or wear a mask. This week’s JAMA has a commentary by the ethicist Art Caplan and New York’s Commissioner of Health, Dr. Nirav Shah. In the JAMA piece they argue the ethical imperative underlying the mask ruling. You can read about the ruling here and the JAMA commentary here (free full text). Unvaccinated HCWs will be required to wear the mask during periods of widespread influenza activity. It’s important to note that over the past 6 years, the period of widespread activity in New York varied from 11 to 22 weeks. That’s a long time to wear a mask, which is required in any area where patients are typically present. The document notes that this includes the cafeteria, though the unvaccinated worker is allowed to be mask-free when eating.

For many reasons, I dislike mandatory influenza vaccination. But I despise the mask regulation. I have to question the rationale. It seems to me to be less about ethics and more about being coercive and punitive. It’s wasteful. There have been periods of time when masks were in short supply with the shortage being made worse by the maskers. Most importantly, wearing a mask for prolonged periods of time is impractical—it’s uncomfortable and distracting. If we are going to argue for masking on an ethical basis, since influenza vaccination is only 60% effective at best, wouldn’t it be consistent to argue that all healthcare workers, vaccinated and unvaccinated, should wear a mask? It's also laughable that the ethicist doesn't mention that it's unethical to come to work while sick with influenza, which studies tell us is quite common. Presenteeism remains the elephant in the middle of the room, and reducing it is likely far more important than mandating influenza vaccine or masks to prevent transmission of infectious diseases in the healthcare setting.

Photo: REUTERS/Yuri Maltsev

The lunacy continues

It appears that an increasing number of hospitals are requiring healthcare workers that are not vaccinated against influenza to wear masks (see a recent example here). I have yet to see any evidence to support such a policy, and I'm not even sure of the purported intent (is it to prevent infection of the unvaccinated HCW, or is it to prevent the infected HCW from transmitting to patients?).

Whatever the intent, it seems completely impractical. Wearing a mask for 8-12 hours is uncomfortable and an unnecessary distraction. I suspect it also impacts morale. So none of this makes sense to me, but neither does mandatory influenza vaccination.

Last week, the Massachusetts Nurses Association characterized the mask policy as an act of bullying. That's a strong word, but after thinking this over, I admit that I have to agree. I don't think the mask requirement has been promulgated to reduce transmission of influenza; rather, I suspect it's to punish those who don't comply with vaccination. So here we have a mandate that doesn't make sense, aimed at those who don't comply with another mandate that doesn't make sense. And the lunacy continues....

Photo:  3M

The surgical mask for the non-surgeon



Photo: LesterHo

My favorite section of GQ magazine is the column, The Style Guy, in which Glenn O'Brien solves sartorial conundrums. The June issue has a question from a reader asking whether it's ok to wear a surgical mask with a suit when you're recovering from the flu and want to get back to work. Here's his response:

In Japan the surgical mask is more normal than a hat. Ths is sometimes because of Japanese courtesy, keeping their germs to themselves; sometimes because of their fear of germs; and sometimes in homage to Michael Jackson. In America you can't pull the mask off with anything but scrubs. My position is, if you're sick enough to be contagious, stay the hell home.

There you have it. Even the Style Guy is down on presenteeism.

New CDC proposed guidance for influenza control

CDC recently posted proposed guidance on prevention of seasonal influenza in the healthcare setting. Written comments on the proposed standards will be accepted through July 22, 2010. The intent of these guidelines is to replace prior CDC infection control recommendations for seasonal and H1N1 influenza. In a nutshell, CDC is proposing droplet precautions, except when aerosol generating procedures are being performed, in which case airborne precautions should be followed. To see the document click here.

Who is that masked...college student?

Researchers Allison Aiello and colleagues at the University of Michigan just published a study in the February issue of JID that assessed the benefit of (a) face masks or (b) face masks + hand hygiene vs. (c) control in preventing ILI in college residence halls (dorms) during the 2006-7 flu season. Each group (cluster) consisted of either one very large hall or a combination of 3 smaller halls (2 groups) for a total of 7 randomized halls. 1297 students were included in the study. Interestingly, spring break occurred during the study period which may have impacted the results. To bad the analysis couldn't tell us whether heading to the beach or skiing reduced the risk of influenza. In any case, they reported significant reductions in ILI in the mask+hand hygiene group during weeks 4-6 and in the mask only group during weeks 4-5 after influenza was first detected on campus.

An accompanying editorial by Titus Daniels and Tom Talbot, both at Vanderbilt, places the new findings in the context of the recent H1N1 'pandemic' and the N95 respirator debate. Importantly they suggest that the benefits seen in both face mask arms of the study may have been secondary to reduced viral shedding from infected mask wearers. They are correct to point out that the Michigan study supports the benefits of hand hygiene and it was also great to see them re-emphasize the importance of annual vaccination, particularly in health care workers, staying home when sick and compliance with proper respiratory etiquette.

Note: Both the article and editorial full-texts are available for free on the JID website; which is very nice for all who don't have a personal or university-based subscription.

A video worth a thousand words

This week's New England Journal of Medicine has a video using Schlieren optics demonstrating the plume created by a cough with no mask, with a surgical mask and with an N95 mask.The masks redirect the plume upward which may reduce the risk of transmission of respiratory infections.

Schlieren photography allows visualization of transparent material that is not visible to the human eye. The Schlieren photo of a cough shown here (with no mask) is from the New York Times (10/28/08) by Madeleine Robins.

I'll beat a dead horse...

See here for CNN's coverage of the swine flu mask debacle, which is well written and a primer for anyone who hasn't been following the debate.

Save the masks!

In our flu planning meeting yesterday I learned from our materials management director that we are having difficulty obtaining surgical masks and that our in-house supply is being depleted. Whether this is a local problem or whether it's more widespread I don't know. But it concerns me that hospitals are implementing policies requiring asymptomatic healthcare workers to wear surgical masks at all times, in some cases those refusing to get vaccinated, in other cases universally in high-risk areas of the hospital. Perhaps we all need to take a step back and think through the long-term implications of such policies.

It seems to me that we are seeing an exceptionalism applied to H1N1 much like that applied to MRSA--that is, we are singling out certain diseases to focus attention and apply interventions while other diseases or organisms, perhaps of equal risk and impact, are not given the same attention. With regard to H1N1, the two major differences from seasonal influenza being observed are a larger population of susceptible individuals due to the antigenic shift the virus has undergone and the overall milder disease course (though there are certainly severe cases being reported). So if you think that all healthcare workers, or even just the unvaccinated fraction, should wear masks at all times during H1N1 season, are you prepared to do the same in all subsequent influenza seasons? Even if the flu season is prolonged? Even if the vaccine and circulating strains are mismatched, meaning in essence that all healthcare workers are unvaccinated? What are the triggers for starting and stopping masking? Is prolonged mask use a practical strategy? I could go on, but you get the point, I'm sure. I think a lot of policy is being driven by the media's attention on certain diseases and organisms with a short-term focus, rather than on priorities that are grounded in the magnitude of risk and impact and the long-term implications. Perhaps key questions to ask are: How many patients died in your hospital in the last month from a catheter-related bloodstream infection? How many died from ventilator-associated pneumonia? How many died from a surgical site infection? And how many died of nosocomial H1N1?

I long for the post-H1N1 era......

A must-read for germophobes

For those of you who are really worried about swine flu, today's New York Times has an interesting article and video of Ariel Kaminer, the Arts and Leisure editor, going about the city in full personal protective equipment--a jumpsuit, mask, gowns and goggles.

Photo:  Patrick Andrade for the New York Times

IOM & face masks: Efficacy vs effectiveness

Yesterday's report from the IOM on respiratory protection for healthcare workers against H1N1 was quite disappointing. Unfortunately, IOM evaluated the question from the standpoint of efficacy (how well an intervention works in an ideal setting) rather than one of effectiveness (how well an intervention works under real world conditions). Effectiveness takes into account compliance, which is likely to be an issue when levels of disease activity rise and healthcare workers spend more of their day wearing a mask. But more importantly, the current supply of N95 masks appears to be insufficient for them to be used when encountering all patients with suspected swine flu. I don't disagree with IOM's conclusion that N95 masks are more protective then standard masks, but to ignore logistics and practicality when making a recommendation is of little help to those of us in the trenches. I received several emails yesterday from hospital epidemiologists at academic medical centers who stated they would not follow the IOM recommendation but continue with SHEA's recommendation (i.e., use of a standard mask except for aerosol generating procedures).

The short end of the just-in-time stick

This morning's Boston Globe has an article on problems with the medical supply chain unmasked by the H1N1 outbreak. Some of the difficulties relate to a just-in-time supply strategy, which was developed by the automotive industry and philosophically views inventory as waste. So when an outbreak of disease emerges abruptly, hospitals find themselves quickly exhausting supplies of masks, testing swabs, and medications. This is another example of the problems that occur when healthcare is fundamentally viewed as a commodity rather than as a public good.