There are some simple responses to these arguments: All eligible people 12 and above — including those who were previously infected such as that professor — would be better off getting the vaccine and should be required to do so. Vaccines for younger children must be an urgent priority and, once authorized, should also be mandated.
Nevertheless, it’s important to acknowledge that those promoting natural immunity aren’t entirely wrong. They are right that recovery from covid-19 provides good protection from reinfection. They might even make a reasonable case that those who had the disease don’t need both doses of the vaccine. Where they go grievously wrong is when they encourage people to forgo vaccination and instead opt for infection.
Studies have compared whether infection or vaccination confers stronger immunity. Some research suggests that vaccination provides more durable and more consistent protection than recovery. Others reach a different conclusion; a new study from Israel, not yet peer-reviewed, found there was a lower risk of infection with the delta variant among those with immunity from recovery compared with vaccination.
Indeed, for many other diseases, natural infection results in better immune protection than vaccination. But the conclusion to draw isn’t that we need to wait for everyone to become infected, because of the price we would have to pay. Children are immunized against measles because some who contract it will suffer permanent brain damage. Even though the United States hasn’t had a case of polio since the 1970s, we vaccinate against it because we want to prevent tragic consequences of irreversible paralysis.
Now that we have safe and effective vaccines against the coronavirus, choosing infection over vaccination runs counter to every principle of public health — and common sense. Even if infection yielded the same or better protection than the vaccine, it makes no sense to risk severe illness and death — not to mention spreading the virus to others.
Moreover, it’s increasingly clear that those who recovered from covid-19 are better protected if they also get vaccinated. Numerous studies have found that vaccination after infection stimulates a substantial antibody response that’s more robust than either recovery or vaccination alone. A report published by the Centers for Disease Control and Prevention concluded that such vaccinated people have half the risk of reinfection compared with previously infected people who remained unvaccinated.
What’s less clear is whether people who recovered from covid-19 should still get two doses of the Pfizer or Moderna vaccines, as the CDC recommends. Several articles have concluded that one dose is sufficient in this population. France, Germany and Italy are among the countries that advise just one dose for those with prior infection.
Then there’s the question of whether prior infection should mean an exemption from vaccine requirements. Israel’s Green Pass that allows access to restaurants, gyms and museums recognizes immunity as either from vaccination or recovery. Should the United States adopt a similar policy?
Here’s where we need to distinguish between questions that have straightforward scientific answers and those that don’t. It is clear that those who have neither been infected nor vaccinated should get their shots now. This is not just about their individual health but about the health of the public and bringing the pandemic to an end. Waiting for natural immunity should not be an option, just as it’s not for measles, polio and other diseases for which we mandate vaccines.
At the same time, we can recognize that there is a difference between those who remain unvaccinated and have never contracted the coronavirus, and those who have some protection from recovery. Perhaps the CDC should evaluate whether one dose of a normally two-dose vaccine is sufficient for people who have had covid-19.
Logistically, however, allowing proof of prior infection as a substitute for vaccination could prove too difficult. Some people might claim to have had a prior infection to get out of a vaccine mandate, and antibody testing isn’t recommended because it’s unknown what level of antibodies signifies sufficient protection. From a policy perspective, I think it’s appropriate for workplaces and schools to decide that because of the proven safety of the vaccines and the added benefit for people with prior infection, they should be required to be vaccinated like everyone else.
It’s possible to both stand behind vaccine mandates and acknowledge the complexity around the topic of natural immunity. Doing so is intellectually honest and adds credibility as we focus the effort to get vaccines to those who need it most urgently: those who have not had covid-19 and are still unvaccinated.