Most Americans have contracted COVID-19. That doesn’t mean they won’t get it again 2022-04-29 07:54:15

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A healthcare worker at a COVID-19 testing site

A healthcare worker at a COVID-19 testing site

A man adjusts a COVID-19 test tent in New York City on April 27, 2022. Credit – Spencer Platt / Getty Images

You likely have COVID-19 – whether you know it or not. Nearly 60% of people in the United States have antibodies in their blood indicate that they were infected with SARS-CoV-2, the virus that causes COVID-19, according to new estimates from the US Centers for Disease Control and Prevention.

But that does not mean that 60% of people in the United States are immune to COVID-19. We know that’s not what this means. “Re-infection is happening,” Dr. Kristi Clark, co-leader of the CDC’s Disease Control and Prevention Task Force, co-leader of the Epidemiology and Surveillance Team, spoke during an April 26 news conference. “Protection from vaccination and protection from previous infections diminish over time.”

Even after two years and millions of infections in the pandemic, researchers are still learning about immunity to the virus, and how long you can expect to stay disease-free after an infection or illness. Here’s what the latest science says about immunity to COVID-19.

If I already have COVID-19, will I get it again?

Your immune system mounts a few different defenses against SARS-CoV-2. White blood cells called B cells produce antibody proteins, which help fight the invader. Meanwhile, T cells, another type of white blood cell, can kill cells that have been captured by the virus.

study From British researchers published in New England Journal of Medicine In March, it found that immunity linked to infection stays strong for up to a year, then begins to wane — while the protection offered by two doses of the Pfizer-BioNTech vaccine begins to wear off in about six months. while, research review Posted in Annals of internal medicine It concluded in April that people who have recovered from COVID-19 are significantly protected from reinfection for at least seven months.

But all this research was done before the advent of Omicron variant, which is more contagious of previous breeds. “We cannot predict how protection will work for the next variant or over a period of time,” says co-author Dr. Mark Helfand, MD, professor of medicine at Oregon Health & Science University.

Children may retain their antibodies longer than adults, According to a new study A researcher at the Indiana University School of Medicine. They found that six months after infection, more children still had antibodies capable of neutralizing the virus than adults.

While these findings should bring some relief to people who have contracted COVID-19, there are no guarantees when it comes to immunity. (A woman in Spain recently made headlines after she tested positive COVID-19 twice, only 20 days apart.) Some people develop more antibodies after infection than others. It’s also not clear how antibody levels correlate with protection against infection, so a positive antibody test doesn’t necessarily mean you’re immune to the virus, Clark said during the CDC conference.

Dr. Bruce Farber, chief of infectious diseases at Northwell Health in New York, says there is no way to say for sure how much a person who has recently recovered from COVID-19 can stop worrying about re-infection. But he did allow that it would be “very unusual” to get COVID-19 within 90 days of a previous case.

If I receive the full vaccination, am I immune to COVID-19?

COVID-19 vaccines also stimulate the body to produce antibodies and stimulate a T-cell response, although these are different from those that the body naturally produces.

Vaccines provide strong, lasting protection against severe illness and death, but their effectiveness against infection wanes over time, so your risk of getting sick decreases soon after your last dose. research review Posted in scalpel In March, it analyzed data from previous studies that evaluated the effectiveness of various COVID-19 vaccines, including those made by Moderna, Pfizer-BioNTech, AstraZeneca and Johnson & Johnson. The researchers found that the ability of vaccines to prevent symptomatic disease across brands decreased by 20% to 30% after six months, although they remained good at preventing severe illness and death. This review was also published before the Omicron variant –Vaccines are less effective– It started spreading widely.

Even with Omicron circulating, however, a vaccinated person was 2.4 times less likely to contract the virus in March than an unvaccinated person, According to the Center for Disease Control and Prevention.

Dr. Jessica Ridgway, associate professor of medicine at the University of Chicago who co-authored it, says anyone who is unvaccinated, whether or not they have COVID-19, should get vaccinated. A recent study on COVID-19 infection. “It’s incredibly safe, and having that extra level of immunity would definitely be helpful in preventing COVID,” she says. Moreover, research shows that getting Booster dose can help provide protection to higher levels.

What if you receive a vaccination? And Had COVID-19?

if you have He recovered from COVID-19 and got the COVID-19 vaccineYou have what’s known as “hybrid immunity.” Studies show that this type of protection is better From vaccination or exposure alone, because you benefit from both natural and vaccine-derived defenses.

“The best immunity, no doubt in my mind, is hybrid immunity,” Farber says.

Definitely, You should never try to catch COVID-19 In order to acquire hybrid immunity. While it is very unusual for a healthy vaccinated person to have a severe case of COVID-19, complications can occur. People have had COVID long even when they are fully vaccinated And you have few symptoms, for example.

Will I need to keep getting COVID-19 boosters forever?

US Food and Drug Administration (FDA) Recently authorized a second round of reinforcements For people 50 and older, as well as some immunocompromised people across age groups. The use of additional boosters has not been authorized for the entire population yet – but there has been much speculation about whether they will be, because the immunity associated with the vaccine wears off over time.

The Food and Drug Administration’s Vaccine Advisory Committee met in April to discuss ways to do so Simplify and improve your reinforcement strategy Move forward. An annual dose, as with flu vaccines, is a possibility — but SARS-CoV-2 mutates in less predictable ways than the flu virus, so it’s difficult to make a booster in advance that targets any strain that spreads later.

A better model could be the development of enhancers that provide immunity to multiple variants. This science is underway nowbut it is too early to say exactly what future enhancement strategies will look like.

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