LA’s indoor vaccine mandate was supposed to boost vaccination rates and reduce COVID-19 cases. It didn’t.

When Los Angeles imposed one of the nation’s strictest indoor vaccine mandates in November 2021, city officials were adamant that the measure was essential to public health. Americans have been debating these policies for years, but what matters now is evidence, which we now have.

“These new rules will encourage more people to get the shot, and make businesses safer for workers and customers—so that we can save more lives, better protect the vulnerable, and make our communities even safer as we fight this pandemic,” then-Mayor Garcetti told the media, despite protests from residents about their livelihoods. The City Council agreed, claiming that requiring proof of COVID-19 vaccination for indoor activities would “promote the health, safety, and welfare of [Los Angeles] residents…”

But although vaccine mandates were often characterized as scientifically ironclad, and while they sounded logical on the surface, the evidence backing them up was surprisingly sparse. Since similar restrictions had never been implemented in the United States—at least not since statistics on vaccination rates and health outcomes had been regularly collected—there was no historical data to inform decision making. Mostly, policymakers were following their intuitions in a situation full of uncertainty, with perhaps a little “We’ve got to do something!” thrown in.

A new study (co-authored by one of us) provides the first systematic analysis of the effects of vaccine mandates in Los Angeles and the other eight large American cities that took similar steps.

Using several different statistical approaches and comparing hundreds of cities with and without mandates, the authors found no evidence that these measures had any beneficial effect on vaccination rates, COVID-19 cases, or COVID-19 deaths. In fact, the results suggest that Los Angeles’ vaccine mandate may have led to an increase in COVID-19 cases.

It isn’t clear exactly why the mandate was ineffective at blunting the pandemic. One reason might be that it was relatively easy for unvaccinated residents to evade the requirement by going outside the city to eat indoors or attend a concert. Although LA County also had a vaccine mandate for certain indoor activities, its rules were not as sweeping as the city’s. This is consistent with evidence that vaccine mandates in larger jurisdictions, like Canadian provinces and European countries, were more successful in increasing vaccination rates. It’s much more costly to cross a provincial or national border than to travel beyond a city’s limits.

Our findings also suggest that vaccine mandates may have made some people complacent about other measures to slow the spread of COVID-19. Reasoning that indoor spaces were being made safer by excluding the unvaccinated, some people may have visited restaurants and other venues more frequently than they otherwise might have, helping to spread the virus. Likewise, adherence to social distancing, masking, and hand washing guidelines might have declined. Paradoxically, research suggests that “an increased focus on vaccines can lower compliance with public health guidelines and accelerate the spread of infectious disease.”

Evaluating the government’s pandemic policies is crucial if we want to be better positioned to respond to the next health crisis. In the midst of the Omicron wave, city officials were forced to make tough decisions with limited information and little time for careful analysis. Serving the public in such challenging times is not an enviable job. But part of that job is taking responsibility for mistakes. And enacting vaccine mandates was a whopper.

Vitor Melo is a postdoctoral fellow with the Open Health Project at the Mercatus Center at George Mason University, a fellow with the Initiative on Enabling Choice and Competition in Healthcare at the University of Chicago and the coauthor of a new study on indoor vaccine mandates. Liam Sigaud is a research assistant with the Mercatus’ Open Health Project.