When the coronavirus vaccines were first authorized, data showed they were more than 90 percent effective in reducing infection. And when the federal vaccine mandates were first proposed, an unvaccinated person was more than five times as likely to be infected with the coronavirus compared with someone who was vaccinated.
I strongly supported the federal vaccine mandate then for this reason. I also believed, as did many scientists, that it was possible to reach a high enough level of population immunity such that the novel coronavirus would cease to exist — or at least become more akin to measles or chickenpox and limited to localized outbreaks.
The arrival of the omicron variants changed everything. These strains are so contagious — and immunity to them is so short-lived — that even though the Centers for Disease Control and Prevention estimates that more than 96 percent of Americans have been vaccinated, infected or both, the virus is still spreading. Last week, there were nearly 90,000 documented covid infections in the United States, a number that is almost certainly a substantial underestimate because of home testing and scaled-down reporting.
At the population level, immunity is still reducing the severity of the coronavirus, as evidenced by covid hospitalizations and deaths falling to near-record lows. But the difficult truth is that we will not achieve herd immunity and eradicate infection in the foreseeable future.
Much of the shift in circumstances is due to the immune-evasiveness of omicron, which has rendered vaccines much less effective against infection and for a much shorter period. A major study, published in the New England Journal of Medicine last year, found that two doses of either the original Moderna or Pfizer vaccines were only about 40 percent effective against omicron infection in the 14 days to three months following the second dose. The protectiveness was entirely gone by six months.
The good news is that vaccine effectiveness is still strong against severe illness. A new CDC study found that even one to two years after the last dose, the original coronavirus vaccines are 56 percent effective at protecting against hospitalization or death. The bivalent vaccines are probably even more effective against currently circulating variants compared with the original monovalent vaccines, and I’m glad that the Food and Drug Administration and the CDC have allowed vulnerable people to receive a second bivalent dose to “top up” their protection.
The point is that while vaccines are still very much needed, especially for vulnerable people, there is no longer a rationale for vaccine mandates. The federal mandate makes even less sense considering that someone could satisfy it so long as they received two doses of the Pfizer or Moderna vaccines or one dose of the Johnson & Johnson vaccine at any point. That means someone whose last dose was more than two years ago could check the box, even though the protective effects against infection waned long ago.
Moreover, the CDC just changed its vaccine recommendation so that an unvaccinated adult needs only one dose of either the Pfizer or Moderna bivalent vaccine to be up-to-date with their coronavirus immunizations. Continuing to require two doses would be at odds with the CDC’s own guidance.
The administration’s policy change is not without controversy. With the U.S. national emergency for the pandemic set to end on May 11, advocates are understandably concerned that elderly, immunocompromised and other vulnerable groups are being left behind. Policymakers should listen to their demands and do far more to protect high-risk individuals, including focusing resources to keep these groups up-to-date on vaccines and investing in improved treatments. They should also expedite the development of better vaccines that would not only safeguard against severe disease but also reduce infection and transmission.
In the meantime, though, the existing coronavirus vaccine requirement needed to go. The Biden administration should be commended for its actions during the pandemic, including its acknowledgment that when the science changes, policies need to evolve, too.
