COPENHAGEN, February 22 - A Danish study has found that getting infected twice with two different Omicron coronavirus subvariants is possible.
In Denmark, a more infectious sublineage of the Omicron coronavirus strain called BA.2 has quickly dethroned the "original" BA.1 variant, which is the most common worldwide, although it has still been unclear whether a person might be infected by these two variants.
A new study, led by researchers at Denmark's largest infectious disease authorities, the Statens Serum Institut (SSI), claims that people who have been infected with BA.1 may be infected shortly following, but that it is a rare event.
"We provide evidence that Omicron BA.2 reinfections are rare, but they may occur shortly following a BA.1 infection," the study authors said.
BA.1 and BA.2 are divided by up to 40 mutations. While BA.2 accounts for over 88% of cases in Denmark, cases have begun to increase in the United Kingdom, South Africa, and Norway.
Researchers claim that reinfections mainly affected young, unvaccinated individuals, and only caused mild illness, none of which resulted in hospitalizations or fatalities.
The study, which is not yet peer-reviewed, found 1,739 cases between November 21, 2021 and February 11, this year, where people had twice tested positive.
In Denmark, more than 1.8 million infections were registered in the period.
The researchers discovered 47 instances of BA.2 reinfections shortly after a BA.1 infection. It also found less virus material at the second infection, suggesting that immunity was developed from the first infections.