Canadian researchers unlock way to boost immunity against BQ.1.1

However, research from Canada’s University of Montreal shows that a fourth shot of mRNA vaccine plus natural immunity from a recent infection boosts immunity against BQ.1.1.

Posting on Facebook, the centre explained that the Omicron variant has mutated since the end of 2021 to resist monoclonal antibodies and inactivated, viral-vector and mRNA vaccines.

Montreal University researcher Andres Finzi reported that those who have received three doses of mRNA vaccine, either Pfizer or Moderna, have weak immunity to newer strains of Omicron when compared to the Wuhan, Alpha, Beta, Gamma, and Delta strains.

However, the immune response to BQ.1.1 is raised significantly by three doses of mRNA vaccine plus natural immunity. People recently infected by Covid can achieve this level of immunity by getting either monovalent (first-phase Pfizer/Moderna) or bivalent (second-phase Pfizer/Moderna) as their fourth vaccine dose, Finzi said.

Finzi’s Montreal research team also expected the formula to work well against other new Omicron subvariants such as XBB.

The Ramathibodi Hospital centre explained that while second-phase mRNA vaccine may work less well against new subvariants, it is still a good choice for protection while newer vaccines are being developed.

It said people were still getting infected after receiving three vaccine doses. Hence, they should seek a fourth dose 4-6 months after their third shot, to boost immunity against the BQ.1.1 and XBB subvariants that are expected to spread quickly across Thailand in the next few weeks.

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