Will boosting healthcare workers prevent workforce shortages?

Not necessarily. In fact, it could make them worse.

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Last weekend, Dr. Rochelle Walensky, the director of the Centers for Disease Control and Prevention, overruled the agency’s own advisory panel to recommend that people ages 18-64 who are believed to be at high risk for Covid-19 exposure at work—including healthcare workers, teachers, and others—should be able to get booster shots 6 months after receiving an initial series of Pfizer's vaccine.

Like the panel that Dr. Walensky overruled, I believe we lack sufficient evidence that all individuals in this group are more likely to be helped than harmed by booster shots, given the substantial protection vaccines continue to provide and the unknown risks of adverse reactions like myocarditis after a 3rd dose.

But some booster boosters have put forth another argument: that even if healthcare workers are not made individually safer by boosters, boosting them is nonetheless beneficial for society, because it will prevent them from calling out sick due to breakthrough infections, and staving off potential hospital worker shortages.

I was interested by this argument and decided to do a thought experiment to evaluate it.

My conclusion? Given how rare breakthrough infections are, even during the Delta era, and the fact that people often experience significant flu-like side effects after receiving the vaccine, it's not clear that boosting healthcare workers would prevent missed workdays overall. In fact, boosting might end up causing more missed workdays and worsening workforce issues in the near term.

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Thought experiment: Imagine 1 million fully vaccinated healthcare workers ages 18-55 work in a large healthcare system and that they will all go for a Covid-19 booster shot sometime in the next 4 months. How many missed days of work could that cause? Based on data from the initial rollout, around 40% of all vaccine recipients developed flu-like symptoms 1-2 days after their injections. Pfizer’s trial data suggest the number was higher, as 45% of recipients ages 18-55 required fever-reducing medications within a week of the jab. This week, the CDC released some data on side effects after boosters, in its publication Morbidity and Mortality Weekly Report. While it was a small dataset, summarizing just 306 boosted individuals, the rates of common adverse events were similar to those seen after 2nd doses of both the Pfizer and Moderna vaccines. Over 65% of recipients reported any “systemic” reaction; 22% said they could not perform normal daily activities, though just 9% said they were unable to attend work or school. We don’t have breakdowns for healthcare workers, but the data are apt to be similar. That said, it’s more likely that healthcare workers would lean towards having to miss a day or two of work, while workers in other sectors might be able to soldier on. When you’re working in a hospital, you can’t “power through” a fever (which 22% reported), or diarrhea (which 10% reported).

With some quick arithmetic for the million healthcare workers in our thought experiment, we’d find that somewhere between 100,000 and 1 million days of work could be lost in the next 4 months because of boosters, depending on the actual rates of adverse effects, and whether people end up needing to miss zero, one, or two days of work.

Now let’s turn to the likely benefits of boosters.

If boosters decrease infections among hospital workers, even temporarily, fewer members of the workforce will have to isolate for 10-14 days after a breakthrough infection. The question is, how many breakthrough infections can we expect in the coming 4-month period? Massachusetts is now tracking breakthrough infections.* Last week, there were nearly 4,400 breakthrough infections among 4.6 million fully vaccinated (non-boosted) people), or 0.01% per day. If that rate—around 1 in 7,400 per day—continues for 4 months, we can expect to see around 75,000 breakthrough cases during that time. That would translate to around 16,000 breakthrough infections per million people. If those rates apply to our imaginary scenario—which they likely do, despite our worries about hospital exposures—the number of missed days of work by the hospital employees due to breakthrough Covid-19 would likely range between 160,000 and 225,000 days. Recall that these numbers fall on the low end of the number of missed days of work we estimated would occur due to adverse events from booster doses. While it’s possible that infection rates could already be or become much higher, it would take a 4-fold increase to overcome the expected range of missed days of work that we’ve predicted boosters are likely to introduce if everyone boosts soon.

The conclusion is not that boosting all 1 million hospital workers in our scenario would necessarily cause more days of missed work than breakthrough infections would. Rather, the conclusion is that boosting may or may not improve and may or may not worsen the outlook for staff-related hospital capacity issues. What is certain is that if we do not space out boosting among healthcare workers, boosters would clearly cause more hospital capacity problems in the immediate future than breakthrough infections would in most places. The reality is that if hospital workers can avoid infection over the next few months without boosting, that would lead to the fewest missed days of work.

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Obviously avoiding SARS-CoV-2 is not always possible. But remember that data from the CDC (and others) have repeatedly shown that a healthcare worker’s greatest risk of exposure is not at work, but at home. The best way, in my view, to decrease breakthrough infections over the next 4-6 months (i.e. during cold-and-flu season) is for hospital workers to modify their behaviors outside of work, and to reiterate the importance of infection control protocol procedures at work.

Spreading Covid-19 to our patients should be as close to a “never event” as possible. We can achieve close to that with a combination of vaccine mandates, adequate PPE protocol and adherence, and rapid testing to pick up sneaky infections. But leaving our patients, Covid-19 or otherwise, without enough caregivers would be a disaster, which would be especially tragic if it were to be preventable. Yes, it’s still possible that boosting the healthcare workforce could help stave off healthcare capacity overload in some areas. But if we don’t space our boosters out, it’s quite likely that boosting the healthcare workforce now could temporarily decrease rather than increase our numbers on the frontlines.

Comments? Questions? Join the conversation below!

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*I chose to use Massachusetts data because they are reliable and local to me. We could also run this thought experiment using a variety of other datasets. I did exactly that in preparing this article. Using some of the datasets would move the needle towards boosting, and others away from it. So while I can't claim these numbers are "the absolute best ones," I can at least say that they are unlikely to be extreme.