It is very rare for someone to become infected a second time with the coronavirus that causes the disease COVID-19, but the few confirmed cases of re-infection tell us that immunity to the virus is not guaranteed and that vaccination is a regular part of us can be medical. care forward.
There are approximately 50 confirmed cases of reinfection worldwide. This is far less than 1% of the 110 million cases of coronavirus reported worldwide. BNO News, a Dutch news website, monitors reinfections worldwide; 51 confirmed cases of re-infection were identified along with approximately 11,000 suspected or probable re-infections.
Re-infection is suspected to occur when protective antibodies decrease in people who have previously contracted the virus or in people who have contracted the virus without developing antibodies.
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“I do not think anyone had the expectation that if you were to get COVID and overcome it you would never be able to get it again.”
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For some doctors, infectious diseases come as no surprise.
“I think everyone expected that there would be infections again in a distant place after the initial infection,” said Dr. Bruce Polsky, a physician on the disease at NYU Langone Hospital on Long Island, said. “I do not think anyone expected that if you got it, you would never get it again.”
The Centers for Disease Control and Prevention defines reinfection as a positive COVID-19 test that occurs at least 90 days after an initial positive test. (This is to distinguish from people with persistent “long COVID” symptoms.) The Public Health Agency says reinfection is rare; however, it is also said that the number of reinfections will increase as the pandemic continues.
“The likelihood of SARS-CoV-2 re-infection is expected to increase with time after recovery from initial infection due to declining immunity and possible genetic drift,” the CDC said in October.
As the pandemic breaks out in the second year, some of the approximately 27 million people in the U.S. who have already had COVID-19 may be at risk of getting it again.
The length of the pandemic, coupled with the emergence of the new, more contagious B.1.1.7 and B.1.351 variants, could also put people at risk for a second infection with the SARS-CoV-2 virus. The CDC said the B.1.1.7 strain, which was confirmed in 1,523 Americans on Feb. 1, could become the most dominant form of the virus in the U.S. by the end of March. The B.1.351 variant, first identified in South Africa, has been detected in 21 people in the USA
‘As [B.1.351] ‘predominantly, the experience of our colleagues in South Africa indicates that even if you are infected with the original virus, there is a very high re-infection rate to the point that the previous infection does not seem to protect you from re-infection,’ Anthony Fauci, medical adviser to President Joe Biden and longtime director of the National Institute of Allergy and Infectious Diseases, told CNN earlier this month.
What medical research is currently telling us about immunity
Studies on reinfection have so far had mixed findings. A number of projects studying re-infection have been recently announced, including one at the Indiana University School of Public Health in Bloomington assessing the re-infection of COVID-19 in US hotspots and an observational study planning to assess all reported re-infections in France .)
A recent preliminary study investigating Marine recruits who arrived at a base on Parris Island in South Carolina found that the previous infection with SARS-CoV-2 had protected them from re-infection – but only until ‘ to some extent. Marines with lower IgG antibody titers and neutralizing antibodies have a higher risk of reinfection, the researchers found.
Other research highlights the rarity of reinfection. Researchers in Qatar found that less than 1% of the approximately 44,000 people who recovered from one case of COVID-19 received SARS-CoV-2 a second time.
But beyond re-infection risk, there are a number of factors that can affect immunity to the SARS-CoV-2 virus.
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‘Because you do not know how long immunity will be induced, we have the possibility because the virus continues to mutate that it actually mutates to become a cold virus. This is what we really hope for. ‘
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Not all people who contract the virus develop antibodies against it, and some people have antibody levels that are not high enough to protect them.
It is also unclear how long antibodies are stuck. According to the CDC study among health care workers in the 12 states and another study in the same group in Nashville, Tennessee, COVID-19 antibodies decrease after 60 days. indicated that IgG antibodies can last six months or longer.
“Because you do not know how long immunity will be induced, we have the possibility because the virus continues to mutate that it is actually mutating into a cold virus,” said Dr. Stanley Perlman, professor of microbiology and immunology at the University of, said. Iowa. “This is what we really hope for.”
If it were to play out, the virus could be blunted until it simply became an annoying but no longer deadly cold. Colds, these are coronaviruses that have not yet been eradicated, can provide immunity for up to three years. People infected with SARS, or severe acute respiratory syndrome, also a coronavirus, had about three years of immunity.
“Sterilization of immunity” is a term used to describe a type of immunity which means that people cannot contract a virus or the disease caused by a virus. This is most likely not going to happen with SARS-CoV-2. What experts, including Perlman, are now wondering is whether reinfections will cause less severe forms of the disease or be asymptomatic.
“It may well be what happens to people who have mild illnesses and become re-infected with serious illnesses,” Perlman said. ‘I think the protection is much longer. So if someone comes out of the ICU and is otherwise normal, I think they will be protected for years. ”
What we know about re-infection rates in the US
The federal government does not stop re-infections, so the number of re-infection cases in the US is unknown. The page on the CDC website with information on reinfections was last updated on October 27th.
Some states have shared details about possible or confirmed reinfections upon request.
According to California, for example, there are two confirmed cases of re-infection in California out of the 3.3 million people who tested positive for the virus there. About 615 people in Colorado meet the CDC criteria for reinfection, according to a state spokesman. “This is a very small percentage of all cases,” which accounts for an estimated 0.15% of all cases in Colorado, she said in an email. In the state of Washington, there are 716 suspected re-infections, and one confirmed case.
The first documented case of re-infection in the U.S. occurred in a 25-year-old man in Reno, Nev., According to a study published in October in the medical journal Lancet. The individual tested positive in April, had two negative tests in May and tested positive again in June.
His case was identified as part of a genomic sequencing program set up during the Nevada pandemic. (The only way to confirm a reinfection is to sequence both samples to make sure they have different mutations, which occur naturally as the virus spreads from person to person.)
‘If we look at differences in the first sample compared to the original [virus from Wuhan, China] who is absent from the second … proves that they were different, that they set out before they could enter the person, ‘says Richard Tillett, a biostatistician at the Nevada Institute of Personalized Medicine and co-author of the Lancet study .
What to know about reinfection and vaccines
If SARS-CoV-2 does not go away, re-infection may become more likely, even if the virus changes shape to become less lethal or cause less serious illness.
Vaccine developers like Johnson & Johnson JNJ,
and Modern Inc. MRNA,
said they are considering programs to develop COVID-19 boosters or vaccines that will be administered regularly in the future.
“Over the next few years, we’ll get a COVID-19 shot just like a flu shot,” J&J CEO Alex Gorsky told CNBC on February 9. that, but we can keep science up to date with the virus. ”
From now on, the CDC says that people who have been infected once with the virus should still be vaccinated as long as they wait at least two months after a negative test.
The late-stage clinical trials for both authorized vaccines mostly did not study the impact of the vaccines on people previously infected with the virus. But Pfizer Inc. PFE,
with the German partner BioNTech BNTX,
and Moderna told the Food and Drug Administration separately during the review process that there is ‘limited’ data indicating that people who have had the virus may be at risk for re-infection and may benefit from vaccination.
“We have seen here and there some case reports of people being re-infected,” said Dr. Tal Zaks, chief medical officer of Moderna, said in an investor call in January. “But in a context of millions getting infected, I think it’s not essential.”
Some health workers at the Hackensack Meridian Health Hospital system in New Jersey have asked administrators if they should be vaccinated if they are already infected. According to Hackensack CEO Richard Varga, the short answer is yes.
“We put those people in the same PBT,” he said, “because you do not know exactly how long and how effective their immunity is.”