Copenhagen, Feb 23 (IANS): Reinfection with different sub-types of the Omicron variant of Covid-19 is possible, says a new study published by Denmark's Statens Serum Institut (SSI).

However, "this seems to occur relatively rarely in Denmark, and reinfections have mainly affected younger unvaccinated individuals", Xinhua news agency quoted the SSI, Denmark's public health and research institution, as saying in the report published on Tuesday.

"None of the infected individuals became seriously ill, and none required admission to hospital."

According to the study, PCR tests carried out on approximately two million Danes affected primarily by Omicron's sub-types BA.1 and BA.2 revealed that "67 cases in which the same individual had become infected twice at a 20-60-day interval where both infections were due to Omicron sub-types".

According to the study, until December 2021, the majority of those infected with Omicron in Denmark had been affected by BA.1, which was also the most prevalent sub-type worldwide.

However, in January 2022, PCR tests revealed that BA.2 was gradually increasing in prevalence to the point where "this variant currently accounts for most coronavirus infections in Denmark, whereas BA.1 is now seen much more rarely".

The SSI recorded 30,480 new cases and 34 deaths in the past 24 hours, bringing the national totals to 2,637,414 cases and 4,375 deaths since the pandemic began.

The country also registered 124,149 cases of reinfection.