Why new Omicron subvariants are more severe
The lack of immunity from vaccination when the BA.1 subvariant first started to spread has made new subvariants of Omicron more severe than BA.5, a senior virologist has said.
In a Facebook post, Dr Anan Jongkaewwattana, director of the National Centre for Genetic Engineering and Biotechnology's Veterinary Health Innovation and Management Research Group, said that most patients did not have immunity from vaccines when the BA.1 subvariant was spreading initially.
Anan cited the study “Neutralisation of Omicron sublineages and Deltacron Sars-CoV-2 by three doses of BNT162b2 vaccine or BA.1 infection”, which was published on Wednesday.
He said that scientists took natural immunity from BA.1 subvariant to test the capability to prevent new BA subvariants.
The study result revealed that the BA.1 subvariant was different from the original variant and natural immunity could not prevent older variants.
It was similar to how natural immunity from older variants could not also prevent the BA.1 subvariant if a person did not receive the booster dose of vaccines.
He explained that it reflected how the mutation of Omicron subvariants could change suddenly.
Interestingly, Omicron subvariants (BA.2, BA.3 and BA.4/BA.5) that people expected to be similar to BA.1 are true, but they also could evade immunity from BA.1.
He said that the immunity from the BA.1 subvariant could almost certainly not prevent BA.4/BA.5 subvariants.
Anan mentioned that the US Food and Drug Administration wanted new booster doses to target BA.4/BA.5 subvariants instead of the BA.1 subvariant.
However, there might be newer Omicron subvariants in the future and the immunity from the BA.5 subvariant might not be able to prevent them.
