<p>Reinfection with the BA.2 subtype of the Omicron variant of coronavirus can occur shortly after initial infection with the BA.1 strain, according to a Danish study.</p>.<p>With the surge of Omicron subvariants BA.1 and BA.2, a large number of reinfections from earlier cases have been observed, the researchers said.</p>.<p>This has raised questions of whether BA.2 specifically can escape the natural immunity acquired shortly after a BA.1 infection, they said.</p>.<p>The researchers from Statens Serum Institut (SSI) in Denmark selected a subset of samples from over 1.8 million cases of infections in the period from November 22, 2021, until February 11, 2022.</p>.<p>The yet-to-be peer-reviewed study, posted on the preprint repository MedRxiv on Tuesday, identified a total of 187 reinfection cases.</p>.<p>The researchers found 67 cases in which the same individual had become infected twice at a 20-60-day interval, and where both infections were due to Omicron subtypes.</p>.<p>In 47 of the cases, the affected individual first became infected by BA.1 and then by BA.2, they said.</p>.<p>The majority of the infected were young and unvaccinated, and most experienced mild symptoms during their infections, according to the researchers.</p>.<p>The team noted that the difference between the severity during their first and second infection was negligible.</p>.<p>None of the infected individuals had become seriously ill, and none required admission to hospital, they said.</p>.<p>"The study shows that infection with two different Omicron subtypes is possible," the authors of the study noted.</p>.<p>"This seems to occur relatively rarely in Denmark, and reinfections have mainly affected younger unvaccinated individuals,” they added.</p>.<p><strong>Watch latest videos by DH here:</strong></p>
<p>Reinfection with the BA.2 subtype of the Omicron variant of coronavirus can occur shortly after initial infection with the BA.1 strain, according to a Danish study.</p>.<p>With the surge of Omicron subvariants BA.1 and BA.2, a large number of reinfections from earlier cases have been observed, the researchers said.</p>.<p>This has raised questions of whether BA.2 specifically can escape the natural immunity acquired shortly after a BA.1 infection, they said.</p>.<p>The researchers from Statens Serum Institut (SSI) in Denmark selected a subset of samples from over 1.8 million cases of infections in the period from November 22, 2021, until February 11, 2022.</p>.<p>The yet-to-be peer-reviewed study, posted on the preprint repository MedRxiv on Tuesday, identified a total of 187 reinfection cases.</p>.<p>The researchers found 67 cases in which the same individual had become infected twice at a 20-60-day interval, and where both infections were due to Omicron subtypes.</p>.<p>In 47 of the cases, the affected individual first became infected by BA.1 and then by BA.2, they said.</p>.<p>The majority of the infected were young and unvaccinated, and most experienced mild symptoms during their infections, according to the researchers.</p>.<p>The team noted that the difference between the severity during their first and second infection was negligible.</p>.<p>None of the infected individuals had become seriously ill, and none required admission to hospital, they said.</p>.<p>"The study shows that infection with two different Omicron subtypes is possible," the authors of the study noted.</p>.<p>"This seems to occur relatively rarely in Denmark, and reinfections have mainly affected younger unvaccinated individuals,” they added.</p>.<p><strong>Watch latest videos by DH here:</strong></p>