Should Health Care Workers be Required to Receive Flu Shots?

Should health care workers be forced to get flu shots? It’s a question that has stirred debate about the merits of policies aimed at protecting patients from influenza infection, especially in parts of the country where vaccination is a condition of employment. As it turns out, the requirement is based on flimsy clinical evidence. That’s according to Gaston De Serres, MD, PhD, a medical epidemiologist at the Institute National de Sante Publique du Quebec, who decided to take a second look at the studies that are most often referenced to back mandated vaccination for health system employees. What he found is sure to please providers and policymakers who think vaccination should be voluntary, not mandatory.

Why did you take a second look at the relevant data?

There are several jurisdictions in Canada and the United States that have a mandatory immunization or vaccinate-or-mask policies in place. We wondered about the scientific evidence underpinning these policies. There’s an interesting phenomenon going on in which hospital administrators are relying on secondhand reports of good scientific evidence to support the policies they’re putting in place to prevent disease in patients. But nobody had gone back to the source studies to find out how much sense they really made. That was the starting point of our research.

What did the studies show?

We looked at 4 cluster randomized control trials that have repeatedly been referenced as the strongest scientific evidence that backs vaccinating healthcare workers to prevent patient disease and death. We found that all 4 trials failed the basic test of expected rates of reduced influenza in patients if vaccine coverage among healthcare providers was increased. The problem with most of the studies was that they looked not only at influenza infection, but also at patients who presented with symptoms of influenza-like illness (ILI). During the winter season, tons of people become sick with respiratory infections, but less than one-third of those cases are due to influenza. We know that the vast majority of ILI cases are not caused by influenza and therefore the flu vaccine has no impact.

Why were the reported results implausible?

We revisited one of the study’s results, which have been widely reported in promoting mandatory immunization. The researchers said 8 healthcare workers would need to be vaccinated each year to prevent 1 patient death. Based on the number of healthcare workers in the United States, that would prevent the same number of deaths that occurred during the entire 1918 Spanish flu pandemic. That makes no sense. If it were true, the vaccination of healthcare workers would absolutely have to be mandatory.

Is it possible to determine if healthcare workers infect patients?

Hospitals track cases of nosocomial influenza, but it’s not specifically known what causes influenza that occurs after patients are admitted — patients could be infected by hospital visitors, other patients with influenza, or a healthcare worker vaccinated with an ineffective vaccine. All of these potential sources outside of unvaccinated healthcare workers have to be included in research that’s used to mandate healthcare worker immunization. At the end of the day, we have to acknowledge that it’s unknown how many hospitalized patients acquire influenza from healthcare workers in general and from unvaccinated healthcare workers in particular.

So do you think healthcare workers should be vaccinated?

The vaccine offers direct protection of healthcare workers who are vaccinated and likely indirect protection to their patients. On that basis, recommending the voluntary vaccination of healthcare workers is justified. That’s completely different than mandating immunization. I’ve received the vaccine annually since 1981 for the purpose of protecting my patients. I do it voluntarily, and would not want to see a colleague get fired because they refuse to get vaccinated. The bottom line is that mandatory vaccination is a policy that’s driven by ideology and justified with studies that use flawed methodology and that cannot be considered valid evidence.