Visitors to the National Academy of Sciences (NAS) in Washington, DC are given a clear reminder that, 3 years after the World Health Organization (WHO) declared COVID-19 a pandemic on March 10, 2020, c is far from over. Before entering, they must show a guard proof that they have been vaccinated against COVID-19. Such requests were common around the world a year ago, with widespread support from infectious disease scientists and public health researchers. But to date almost everyone has had natural infections with SARS-CoV-2 or been vaccinated against the coronavirus – sometimes both – and it has become clear that vaccine-induced immunity is rapidly losing its ability to prevent infection and the spread of the latest variants. Some now say that the mandates are exceeded.
The continuing demands are “puzzling to say the least,” says Heidi Larson, an anthropologist at the London School of Hygiene & Tropical Medicine and director of the Vaccine Confidence Project. She spoke this year at a major infectious disease meeting that required all attendees to show they had received two doses of a vaccine, without needing a recent booster. “It’s not like it’s going to mitigate the spread.”
Larson and other vaccine acceptance researchers who spoke to Science all point out that COVID-19 vaccines clearly prevent serious illnesses, but they worry that keeping the mandates will undermine future public health efforts. “Having to show these old proofs or vaccination certificates really doesn’t make sense, and it could cause damage, because people could lose confidence in the competence of the organization,” says University of Konstanz psychologist Katrin Schmelz , whose research found that institutional trust is crucial for the acceptance of health policies.
Warrants became common in 2021 and early 2022, after the Delta variant caused new spikes in COVID-19-related hospitalizations and deaths, especially among unvaccinated people. Across Europe, people had to show they were fully vaccinated before entering restaurants, shops, museums and concert halls. The United States has required federal employees to be fully vaccinated to keep their jobs. Singapore has imposed a similar mandate on all employees, both public and private. And in February 2022, after months of debate, Austria passed one of the world’s first nationwide vaccination mandates, requiring the vaccines for all residents over the age of 18 and imposing fines on those. who refused.
In many places, the mandates drew great protests, but the rationales seemed compelling. COVID-19 vaccines offer powerful protection against serious illnesses, so the measures promised to prevent hospitals from being overwhelmed. Early data also suggested that vaccines reduced overall infections and shortened how long a person was infected. “If you can only transmit for 3 days, that’s much better than 7 days,” says Angela Branche, an infectious disease expert who studies vaccine effectiveness at the University of Rochester.
Initial hopes that vaccines would stop the spread of COVID-19 faded, however, as it became clear that protection against infection wanes after a few months. New variants that could circumvent vaccine-induced immunity have further undermined hopes that vaccines could curb the spread.
In April 2022, researchers from the UK reported in The New England Journal of Medicine that, based on the health records of over 1.5 million people, protection against symptomatic COVID-19 with the Omicron variant fell to zero 25 weeks after a second injection of the AstraZeneca vaccine and to just 9% 25 weeks after a second dose of the Pfizer-BioNTech Vaccine. A booster dose boosted protection above 60% for a month or two, but after 10 weeks that protection had also started to decline. (Protection against serious diseases persists longer.) Now that more and more people have some immunity after natural infections, the real benefits of vaccines have become even harder to measure.
Many places and groups quickly lifted their vaccine requirements or stopped enforcing them. In June, Austria repealed its law. Most European countries that required vaccine “passes” for shopping, dining out, etc., dropped them by summer 2022. In October, Singapore announced it was lifting its vaccination mandate, and 1 month later the German Minister of Health announced that even for healthcare workers, his vaccination requirement would be allowed to expire. Because being vaccinated was no longer a significant protection against infections with the new variants, he said, “there is no longer a reason”, epidemiologically, for the mandate.
Compared to Europe and Asia, the United States appears to be sticking more closely to vaccine mandates. Many American scientific groups, including NAS and AAAS (publisher of Science) still require their employees and all attendees at events and meetings to be vaccinated. Many universities continue to require vaccinations or booster shots for students, staff, or both.
Although the US government stopped enforcing a federal employee warrant last year in the face of legal action, it retains other requirements. Foreign citizens entering the country must always show that they have received a course of WHO-approved vaccines, a requirement that made headlines last month when tennis star Novak Djokovic, who is not vaccinated, requested an exemption to participate in the March tournaments in Florida. (His request was denied.)
Scientists traveling to certain meetings face similar demands. Those attending the American Astronomical Society’s annual gathering in January were required to upload proof of vaccination, including a booster, before registering for the meeting. Larson and other attendees at the Conference on Retroviruses and Opportunistic Infections, held in February, had to show that they had received two doses of a vaccine. At the AAAS annual meeting this month, in-person attendees also had to confirm they had been vaccinated, but on an honor system.
None of these meetings specified that the vaccination had to be recent, so attendees at some of the gatherings may have received their last vaccination more than 18 months ago. The meetings also did not accept evidence of SARS-CoV-2 infection, recent or otherwise, as an alternative. That makes no sense to Maxwell Smith, who studies public health ethics at Western University. “If they say you must have been vaccinated, but nothing about when those vaccines were received, or nothing about recent infection, then of course that’s less likely to meet the goals” of reducing transmission and infections, he says. “It would be more justifiable to say you must have had a vaccine or been infected within the last 3-6 months, for example.”
Political scientist Katie Attwell, who studies vaccine policy and acceptance at the University of Western Australia in Perth, agrees. Asking for just two doses at some point in the past “feels weird and overwhelmed,” she says. “If it was a living policy, you would mandate the boosters.”
Branche echoes concerns that many of the lingering mandates could be counterproductive. “We don’t want people to think they are safe from getting infected or passing on the virus because they had the primary series 2 years ago. That’s just not true,” she says, adding that such policies could also discourage people from getting more vaccinations.
Others say the conference’s vaccine requirements could replace more effective ways to prevent the spread of COVID-19. “If I were to see a meeting that had a vaccine requirement but then I put everyone in the standard ballroom chairs shoulder to shoulder with no mask requirement, I might not consider that meeting to be seriously focused on COVID protection,” says the University of Maryland School of Medicine. epidemiologist Meagan Fitzpatrick, who models infectious disease transmission. “The vaccine requirement does not allow abandoning all other efforts that one might be able to make.”
Many organizations are reviewing or revising their vaccine policies, especially as the end of the US COVID-19 emergency declaration, scheduled for May 11, approaches. NAS, for example, said Science he is reassessing his current mandate. The University of Michigan, which had required all students, faculty and staff to be vaccinated and given a booster dose, announced in February that only students living in on-campus housing would be subject to a warrant. They will be required to have a dose of the bivalent booster, available since September 2022 and designed to protect against the original strain of SARS-CoV-2 as well as Omicron.
Rob Ernst, the university’s director of health, says the bivalent recall requirement means that by the start of the fall semester, all residents will have had a recall less than a year old. And the rule is still necessary, he argues. With up to 1,200 students living in some halls of residence, “the potential for disruption is greatest in this area”. After 3 years, Ernst says, “We still have significant COVID in our community.