Immunity acquired from COVID-19 infection ignores risks of contracting the disease

A headline circulating online claims that a study in Israel shows that people who have recovered from COVID-19 are better protected against the virus than those who have only been vaccinated.

The title is from a item on the conservative Gateway Pundit website, which calls the vaccine “experimental” and calls Dr Anthony Fauci, the country’s leading epidemiologist, “fuhrer.” The title reads:

“A new Israeli study finds that fully vaccinated people are at ‘greater risk of hospitalization’ and 13 TIMES MORE LIKELY to catch Covid-19 than those who have recovered and have natural immunity. “

The title was shared on an Instagram Publish this was reported as part of Facebook’s efforts to tackle fake news and disinformation on its news feed. (Learn more about our Partnership with Facebook.)

The title accurately reflects some of the study’s findings, but ignores the study’s limitations, including the fact that only one vaccine has been tested and other studies have found COVID-19 to be very dangerous. larger for people who have not been vaccinated.

Without that context, the headline leaves the impression that it’s safer to contract COVID-19 and hope to recover than to try to avoid it by getting vaccinated. This is not true.

The study

The to study is what we call a preprint, which means it has yet to be verified by experts. It was posted on August 25 on medRxiv.com, which added this note: “This article is a pre-publication and has not been peer reviewed. It reports new medical research that has not yet been evaluated and therefore should not be used to guide training. “

The study was conducted by researchers at the Maccabi Research & Innovation Center of Maccabi Healthcare Services in Tel Aviv. They reviewed patient records from the Maccabi health system – 674,000 fully vaccinated and 105,000 infected patients. Of the 105,000 people infected, 63,000 were not vaccinated and 42,000 had received a dose of Pfizer three months after recovery.

The researchers said the study is “the largest real-world observational study comparing natural immunity” acquired from coronavirus infection, with the immunity provided by the Pfizer-BioNTech vaccine. They reviewed patient charts from June to August 2021, when the delta variant was dominant in Israel.

They found:

• People who received both doses of the Pfizer vaccine in January or February 2021 were 13 times more likely to get a delta variant infection than unvaccinated people who had COVID-19 during the same time period had to be re-infected.

• Over a longer period of time – with infection occurring anytime from March 2020 to February 2021, when different variants were dominant in Israel – fully vaccinated people in the study were six times more likely to be infected and seven times more likely to be infected. more likely to suffer from a “symptomatic illness”. “than the unvaccinated people in the study.

• The study “demonstrated that natural immunity provides longer lasting and stronger protection against infections, symptomatic illnesses and hospitalization due to the delta variant”, compared to immunity induced by the two-dose vaccine. from Pfizer, although those previously infected obtained additional protection with just one dose. vaccine.

Caution in interpreting the results

The study was fine has received through some experts as an indicator of the strength of natural immunity. But this has limitations, including the fact that it was done through chart reviews, which are limited through biases in healthcare seeking behavior – such as testing, wearing masks and social distancing – which may differ between the groups compared, said Dr. Matthew Laurens. from the Center for Vaccine Development and Global Health at the University of Maryland.

“This type of study design is not as robust as a prospective study that tracks individuals over time, tests them at regular intervals, and systematically collects symptom data,” he said. “Prospective studies should be conducted to determine if these results can be replicated.

Assessing immunity by comparing COVID-19 reinfection rates among the unvaccinated with breakthrough infections among the vaccinated ignores the dangers of contracting COVID-19 in the first place and the protections against serious illness provided by vaccines. as we have reported:

• At the end of July, people vaccinated represented a upper percentage of new COVID-19 cases in Israel than unvaccinated ones. (This is not unexpected, as Israel has a high overall vaccination rate.) 88% effective in preventing the need for hospitalization and 91% effective against serious illnesses.

• Israel’s first vaccination campaign, which resulted in more than 60% of its population being fully immunized, has resulted in huge reductions in severe cases and deaths in the country.

• In August, we rated False a claim that it is safer to be vaccinated than not to be vaccinated. Studies in the general adult population in the United States show that Moderna and Pfizer-BioNTech vaccines have an 86% to 89% effectiveness rate against infection and a 96% effectiveness rate against hospitalization, according to at the Federal Centers for Disease Control and Prevention. Early evidence from Johnson & Johnson / Janssen vaccine also shows effectiveness against COVID-19, but more studies are underway, CDC noted.

“The suggestion that it might be better to be infected rather than vaccinated fails to take into account the inherent risks associated with COVID-19 infection, including death,” Laurens said. “Vaccination is the best prevention. This has been clearly demonstrated in several prospective, randomized, double-blind clinical trials, which are of the highest quality for clinical studies.”

Experts Recount the journal Science that seeking immunity through deliberate infection would put unvaccinated people at significant risk of serious illness and death, or of persistent and significant symptoms of what has been dubbed Long COVID.

The Maccabi study shows the benefits of natural immunity, said Marion Pepper, an immunologist at the University of Washington, but “does not take into account what this virus does to the body to make it happen.”

Our decision

A headline that circulated widely on social media said: “New Israeli study finds fully vaccinated people at ‘greater risk of hospitalization’ and 13 times more likely to catch COVID-19 than those who have recovered and have natural immunity. “

The study, which was not peer-reviewed, found that people who had been infected with COVID-19 had better protection against reinfection with the delta variant of the virus than people vaccinated against the infection.

But the title’s suggestion that people would be better off not being vaccinated ignores the fact that peer-reviewed studies have repeatedly shown that vaccinated people are more likely to avoid hospitalization or death if they are. infected.

The statement is partially correct but leaves out important details. We rate it as half true.