The natural immune protection that develops after a SARS-CoV-2 infection is a stronger shield against the delta variant of the coronavirus than the Pfizer-BioNTech vaccine, according to a study from Israel.

The newly released data showed that people who had been infected with COVID-19 were much less likely to get the delta variant of the disease, develop symptoms from it, or become hospitalized due to the virus. The same study showed that those who have gotten their full doses were six to 13 times more likely to get infected compared to unvaccinated individuals who were previously infected with the disease.

The researchers also found that those who were previously diagnosed with COVID-19 were more protected against reinfection than those who were vaccinated.

This new work could further discuss whether previously infected people need to receive both doses of the Pfizer vaccine or a similar mRNA one from Moderna.

Vaccine mandates don’t exempt those previously infected; current recommendations still stand that they should be fully vaccinated.

The study examined the medical records of tens of thousands of Israelis, charting their infections, symptoms, and hospitalizations between June 1st and August 14th, when the delta variant surged in the country.

This is the largest real-world observational study so far which compares natural and vaccine-induced immunity to SARS-CoV-2. The massive surge of infections in Israel seems to have been a disaster, and the Israel vaccine crisis should serve as a warning to the rest of the world. 

Natural immunity better than vaccination

Charlotte Thålin, a physician and immunology researcher at Danderyd Hospital and the Karolinska Institute, said that the case in Israel is a textbook example of how natural immunity is better than vaccination. “To my knowledge, it’s the first time [this] has really been shown in the context of COVID-19,” she said.

The new analysis relies on the database from Maccabi Healthcare Services, which enrolled about 2.5 million Israelis.

Led by Tal Patalon and Sivan Gazit, the research found that never-infected individuals who were vaccinated in January and February are six to 13 times more likely to get infected than unvaccinated individuals who were previously infected with the disease.

In one analysis comparing more than 32,000 people in the health system, it showed the risk of developing symptomatic COVID-19 was 27 times higher among the vaccinated, and the risk of hospitalization, eight times higher.

Data shows that people who recovered from SARS-CoV-2 infection continue to develop coronavirus-targeting antibodies for up to a year. In contrast, fully vaccinated individuals stop seeing increases in antibodies a few months after they receive their second dose.

Still, Thålin and other researchers emphasized that deliberate infection among unvaccinated people would put them at significant risk of severe disease, death, or lingering symptoms of COVID. The study showed the benefits of natural immunity, but “doesn’t take into account what this virus does to the body to get to that point,” says Marion Pepper, an immunologist at the University of Washington, Seattle.

This is especially concerning considering that the COVID-19 pandemic has already killed over 4 million people worldwide, and delta and other variants are known to be deadlier than the original virus. Moreover, a new study also raised concerns over the mRNA vaccines’ effectiveness. Pfizer COVID-19 vaccine, for instance, was found to only be 42 percent effective against the delta variant.

Naturally acquired immunity is more powerful than vaccine-induced immunity for many infectious diseases, and most often, these immunities last a lifetime.

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