Growing scientific evidence supports vaccination provides a strong immune response, even in those who have already had COVID-19

While United States Faced with its difficult vaccine launch, an alarming increase in coronavirus cases across the country has resurfaced a latent question: Do people who have already had COVID-19 get vaccinated?

The natural immunity It is a powerful force against certain diseases, like chickenpox and measles. Surviving a natural measles infection may produce comparable, or in some cases superior, immunity to vaccination, depending on Ruth Karron, pediatrician and professor of Johns Hopkins Bloomberg School of Public Health in Baltimore.

But first, of course, the patient must survive.

It is also not yet clear whether immunity against COVID-19 is as powerful as protection against a vaccine. What is evident is that available vaccines are crucial defenses against serious illness and death, even against more contagious variants like Delta. And research shows that even a single dose of an mRNA vaccine from Moderna or Pfizer-BioNTech increases the immunity of people who have had the disease.

“I would recommend anyone who has not been vaccinated to get vaccinated as soon as possible”explained to National Geographic Allison Greaney, researcher of Fred Hutchinson Cancer Research Center in Seattle, adding that vaccines “protect us so well against a very dangerous virus”.

More robust antibodies

In Fred Hutchinson, Greaney He led a research team that published a recent study which suggests that vaccines give people a significant advantage over natural immunity. The team analyzed the antibody people who had recovered from COVID-19, as well as people who had received two doses of the mRNA vaccine from Modern as part of the Company’s Phase I trial.

Researchers found that both groups generated antibodies directed against the receptor binding domain, or RBD. As the name suggests, this part of the SARS-COV-2 virus helps it adhere and eventually enter human cells, causing infection. If the antibodies bind to RBD, they can neutralize the virus.

The investigation revealed that antibodies from COVID-19 patients recovered mainly adhered to an area of ​​RBD that includes the E484 site, part of the virus that has mutated into some variants. On the contrary, antibodies in vaccinated people linked more broadly by the domain, that allowed them to target areas still present in certain variants, including Beta, Gamma and Delta.

El SARS-CoV-2 makes “great efforts” to hide his RBD, using molecular tricks to make the region difficult for antibodies to find, as it is the most vulnerable part of the virus, he says Amy Hartman, Associate Professor of Infectious Diseases and Microbiology at the University of Pittsburgh. But the vaccines MRNA is it so designed to attack RBD and provide it with strong antibodies. And the new findings suggest that mRNA vaccine immunity “appears to be more robust than natural immunity in many cases”, underline Greaney.

Researchers already knew that COVID-19 vaccines “reliably induce antibody levels” which are as high or even higher than those of people cured of severe cases of coronavirus, of Karron, which was not part of the new study. The work of this team of Fred hutchinson show that vaccination “gives us more antibodies and better antibodies”he adds. “It’s a question of quantity Yes quality”.

So why the debate?

However, other research supports that natural immunity to COVID-19 could be strong. A team of researchers evaluated 254 people up to eight months after recovering from COVID-19 and finding that they had “extensive and lasting immune responses”. This was true even for those who had only suffered from mild illness, according to their study, published last month.

Scientists know that other diseases can confer long-lasting natural immunity. After a single infection of varicella, a person is likely to have lifelong immunity to the itchy and sometimes fatal disease. To get the same long-lasting immunity from a vaccine, that person would need two injections, years apart.

But before chickenpox vaccines were developed, about 10,000 American children and adults were hospitalized with the disease each year, showing symptoms such as lung and blood infections.

“For SARS-CoV-2, i can’t dispute that [la vacunación o la inmunidad natural] one is necessarily better than the other based on all of your knowledge of this particular virus, ”he says. Charlotte Cunningham Rundles, professor of immunology David S. Gottesman in the Mount Sinai School of Medicine in the town of New York. But he hastens to add: “I don’t think anyone has collected enough data to say that a person who has had this virus alone does not need to be vaccinated.”

Karron also points out that One of the “big unsolved mysteries” of SARS-CoV-2 is why some people have mild or asymptomatic illness, while others have serious infections. Similarly, scientists are still struggling to understand when and why some people will develop stronger immune responses than others.

For example it says Hartman, studies have shown that some cured patients can mount effective defenses against COVID-19, but the antibody levels dropped rapidly in the other infected people. Scientists continue to collect data and compete against each other to answer this key question and others, such as how long does immunity last from vaccines or natural infection.

With the vaccination, most people are almost guaranteed to have a strong immune response, And that includes people who have already contracted COVID-19. Multiple studies have shown that even a single dose of an mRNA vaccine increases antibody levels in cured patients, giving them the same maximum response that two injections give to people who have not had the disease.

Currently, More than 97% of people hospitalized for COVID-19 in the United States are not vaccinated. And while a small percentage of those vaccinated have been infected with the virus, their cases are extremely mild. Monday, US Senator Lindsey Graham, who was vaccinated in December, announced that had tested positive for COVID-19 after experiencing only mild symptoms. “I am very happy to have been vaccinated,” the South Carolina Republican said in a statement, “because Without the vaccine, I’m sure I wouldn’t feel as well as I do now. My symptoms would be much worse. “

the CDC reports the 0.0018 percent deaths from COVID-19 from December 14, 2020 to July 19 were among those vaccinated. And this, say the experts, is proof that vaccines work. “For many pathogens, we are a bit humble,” he says. Karron. In the case of certain diseases, such as HIV Yeah malaria“It is not at all advisable to catch it,” he said. “Corn For many pathogens, and especially things like respiratory pathogens, like COVID-19, our goals are a bit more modest. Our goal is really to prevent serious illness and death. “

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