Yahoo News Where does natural immunity stand in fight over vaccine mandates?

With the Biden administration’s vaccine mandate deadline fast approaching, and many states and private employers continuing to require vaccination, many unvaccinated American workers could soon lose their jobs if they don’t comply with these inoculation requirements. That has already been the case for hundreds of health care workers and airline workers across the country who have refused the vaccine.

Among some of the arguments against the COVID-19 vaccine mandates is that immunity from a previous coronavirus infection should count as an alternative to vaccination. This topic has received a lot of attention of late, with NBA players and health care workers speaking out and citing “natural immunity” as what they believe to be a valid reason for refusing to get the shot.

Last week NBA player Jonathan Isaac said at a press conference that he wasn’t getting vaccinated against COVID-19. His reasoning? Natural immunity.

“I would start with I’ve had COVID in the past, and so our understanding of antibodies, of natural immunity, has changed a great deal from the onset of the pandemic and is still evolving,” Isaac said.

The natural immunity argument has also emerged as a potential legal challenge to states and federally mandated vaccination policies.

In New York, a vaccine mandate for more than 650,000 hospital and nursing home workers has prompted a flurry of lawsuits across the state brought by nurses and others who are seeking various exemptions, including one for people who have had COVID-19.

On Thursday a judge upheld the University of California’s COVID-19 vaccine requirement against a challenge by a professor who alleged he was immune to COVID-19 due to a prior coronavirus infection. The U.S. District Court judge overseeing the case said the university system acted rationally to protect public health by mandating the vaccine and not giving exemptions to individuals with some level of natural immunity. The ruling appears to be the first on the issue, and it may influence future rulings on this matter.

But what does the scientific evidence say about which offers better protection — natural immunity or vaccine immunity? The answer is, like almost everything around COVID, complicated.

Dr. Monica Gandhi, an infectious disease specialist and professor of medicine at the University of California, San Francisco, says the data available is mixed, with some studies pointing to natural immunity being as effective as some of the vaccines, and other studies suggesting the opposite.

“When data is mixed, we say we have equipoise and keep on studying,” Gandhi tweeted.

However, the Centers for Disease Control and Prevention and most medical professionals in the U.S. widely recommend the COVID-19 vaccine for everyone who is eligible regardless of whether they have already been infected with the coronavirus.

According to the CDC and health experts supporting this guidance, one reason for this recommendation is that research has not yet shown how long protection from the virus lasts after recovering from COVID-19. In addition, the agency says one of its recent studies, which went through a “rigorous multi-level clearance process,” showed that vaccination offers higher protection than a previous coronavirus infection.

The peer-reviewed study of 246 Kentucky residents concluded that unvaccinated people who already had COVID-19 were more than 2 times as likely than fully vaccinated people to get COVID-19 again.

Dr. Peter Hotez, co-director of the Center for Vaccine Development at Texas Children’s Hospital, told Yahoo News that another reason why those who have had COVID-19 should get vaccinated is because not everyone builds robust immunity after infection.

“If you look at some of those early studies, people who are infected and recover have highly variable heterogeneous responses to the virus,” Hotez said. “Some have pretty strong, vigorous responses. Others have almost no virus, neutralizing antibodies or responses at all, and are highly susceptible to reinfection,” Hotez added.

Since it is difficult to determine where someone may wind up on that scale, Hotez says the best thing to do is to recommend vaccination for those who’ve had the disease already.

But proponents of including natural immunity in the vaccine mandates equation are also basing their argument on scientific data. They point to certain studies over the past year that have shown that natural immunity offers significant protection against reinfection. These include studies out of Cleveland Clinic and Washington University, as well as Israel.

The Israel study, however, has been the one that has received the most attention recently.

According to the 778,658-person study, which has yet to be peer-reviewed, people who recovered from prior infection and remained unvaccinated were 27 times less likely to experience symptomatic reinfection from the Delta variant when compared to those who had not been infected and received two doses of the mRNA Pfizer vaccine. The study also found that a single dose of the vaccine in people with natural immunity boosted protection against the Delta variant.

In response to the Israeli study, Dr. Anthony Fauci, the White House chief medical adviser, said natural immunity was “something that we need to sit down and discuss seriously.” He added that the study didn’t provide information on the durability of the protection from prior infection, and that there is a lot more that needs to be accounted for and studied further when it comes to this topic.

Other arguments that have been brought forth by opponents of the vaccine mandates is that in other countries, for example Britain and Israel, proof of prior infection is taken into account, with people being able to receive a vaccination passport for six months. In the United States, however, that is not the case.

Even though opponents have argued that vaccine mandates shouldn’t be one-size-fits-all, many health experts believe that vaccinating people who have already had COVID-19 is, ultimately, the most responsible public health policy right now. “There’s no doubt that natural infection does provide significant immunity for many people, but we’re operating in an environment of imperfect information, and in that environment the precautionary principle applies — better safe than sorry,” former CDC Director Tom Frieden told the British Medical Journal.

Hotez says this universal vaccination strategy is also the best approach at the moment because of the challenges that exist in testing people’s level of immunity or protection from COVID-19 on a large scale.

“We do have tests to measure antibodies. In theory, you could even measure virus, neutralizing antibodies in a specialty lab, but that’s not easy to do in a high-throughput way,” he said. “We do not have what we call a true correlate of protection. We do not have a blood test or even a series of blood tests that we can say definitively, you know, thumbs-up, thumbs-down, you’re protected or not,” he added.

Finally, health experts say vaccination is simply a more quantifiable, predictable and reliable way to protect the population right now, so Hotez emphasizes the importance of getting the shot, even if you’ve had COVID-19 before.

“The bottom line is that if you’re infected and recovered, you’re still susceptible to reinfection, especially from this Delta variant. … If you’ve not been vaccinated, get vaccinated; if you’ve been infected and recovered, get vaccinated,” he said.

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