The COVID Omicron sub-variant BA.2, informally dubbed the "Stealth Omicron" variant, is ready to reinfect individuals who have already had Omicron, a new examine suggests.
BA.2 has been beneath shut commentary by scientists for a number of weeks after it was reported to be liable for an rising proportion of instances in nations resembling Denmark, the U.Ok., South Africa, and, to a lesser extent, the U.S.
Information means that BA.2 is much more transmissible than the already extremely contagious BA.1 Omicron variant that has been accountable for almost all of Omicron instances worldwide.
One of many key unknown traits of BA.2 is whether or not it's completely different sufficient from BA.1 to have the ability to trigger sickness in individuals who have already had the latter—elevating the likelihood that folks might catch Omicron twice within the few months the COVID variant has existed.
Analysis from the U.Ok. earlier this month had discovered no proof of any such instances. However a brand new examine from Denmark's government-affiliated analysis lab the Statens Serum Institut (SSI) suggests it's certainly doable and has occurred dozens of occasions in Denmark.
It ought to be famous that the examine is a pre-print and has not but gone by the validation technique of peer overview.
The researchers studied information from over 1.8 million Danish COVID instances from November 22, 2021, till February 11, 2022, and chosen individuals who had examined optimistic for COVID twice in that point, primarily based on two optimistic samples returned greater than 20 and fewer than 60 days aside.
This resulted in a complete of 1,739 doable reinfection instances. Upon additional evaluation utilizing genetic sequencing, the researchers discovered that there have been 47 situations of individuals turning into contaminated with the BA.2 Omicron variant shortly after that they had caught BA.1.
The instances had been "largely in younger unvaccinated people with gentle illness not leading to hospitalization or demise," the authors famous. The median age was 15 years.
Of these 47, the overwhelming majority, 42, had been unvaccinated. Not one of the individuals who had caught BA.2 after BA.1 had been hospitalized or died through the follow-up examine interval. Most reported primarily gentle signs.
The examine authors concluded that the BA.1 to BA.2 reinfection fee "seems to be low" however nonetheless highlights the necessity for continued evaluation of how lengthy COVID immunity lasts.
They added that because the majority of individuals reinfected weren't vaccinated, the examine additional emphasizes "the improved immunity obtained by the mix of vaccination and an infection in comparison with infection-induced immunity solely."
Ian Jones, professor of virology on the College of Studying within the U.Ok., instructed Newsweek he was not significantly shocked by the outcomes. "I do not suppose it modifications a lot," he stated. "Simply as Omicron can infect after Delta, so BA.2 can infect after BA.1." He stated the "essential level" was that reported signs had been gentle.
Concern about BA.2 was raised final week after information from Japan advised the variant made animals sicker than BA.1 in lab exams, although consultants famous that information from animal exams is just not all the time helpful for making predictions about people.
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