Unlike at the start of the pandemic, COVID-19 reinfections are no longer rare, with more new variants emerging and raising questions about immunity.
The omicron variant has led to a major shift in “natural immunity”, with many previously infected people susceptible to reinfection with the variant, as well as its faster-spreading subvariants, BA.4 and BA.5 .
In May, Chicago Department of Public Health Commissioner Dr. Allison Arwady said data showed most people infected with COVID are protected from the virus for about one to three months afterwards.
Especially when patients are up to date with coronavirus vaccinations, Arwady said there should be no “major concern” about contracting the virus again soon.
“In the beginning we could confidently, you know, sort of in February, we could really say with confidence that 90% of people weren’t reinfected if they already had COVID,” Arwady said. “It has gone down a bit around the world.”
According to the Centers for Disease Control and Prevention, “after recovering from COVID, most individuals will have some protection against repeat infection.”
“However, reinfections do occur after COVID-19,” the CDC says, adding that changes and mutations “may lead to the emergence of variants that may increase the risk of reinfection.”
In addition to being even more contagious than previous variants, scientists are tracking a mutation in the BA.4 and BA.5 subvariants that may help it evade some immunity and cause reinfections.
A genetic trait reminiscent of the pandemic’s past, known as the “delta mutation,” appears to allow the BA.2.12.1 subvariant” to escape pre-existing immunity from vaccination and infection. earlier, especially if you were infected in the omicron wave,” said Dr. Wesley Long, a pathologist at Houston Methodist in Texas. That’s because the original omicron strain that swept the world didn’t have the mutation.
The genetic change is also present in the omicron BA.4 and BA.5 relatives. These have the exact same mutation as delta, while BA.2.12.1 has one that is nearly identical.
This genetic change is bad news for people who caught the original omicron and thought it made them unlikely to get COVID again soon.
Although most people aren’t sure which variant caused their disease, the original omicron caused a giant surge of cases late last year and early this year.
Long lab data suggests that prior infection with the original omicron is not very protective against reinfection with the new mutants, although the true risk of being reinfected, regardless of variant, is unique to each person and each situation.
According to the latest data, those who were already Delta-sick could have additional armor to ward off New Mutants. A study published before being reviewed by other scientists, by researchers at Ohio State University, found that COVID patients in intensive care with delta infections induced antibodies that neutralized new mutants better than patients who had caught the original omicron.
“The omicron infection antibody does not appear to protect well against subvariants compared to delta,” said study author Dr. Shan-Lu Liu, who co-leads the virus and pathogen program. emerging in the state of Ohio.
But Liu said the level of protection provided by a delta infection depends in part on how long a person has been sick. This is because immunity wanes over time.
People who have become delta-ill should not consider themselves invulnerable to the new subvariants, especially if they are not vaccinated, Long said. “I wouldn’t say anyone is safe.”