Các nghiên cứu về vắc xin Pfizer / BioNTech cho thấy vắc xin vẫn còn hiệu quả nhưng cần tăng cường

This morning (8 December) Pfizer and BioNTech, the makers of the Cominarty mRNA-based vaccine báo cáo that preliminary laboratory studies demonstrate that three doses of the Pfizer-BioNTech COVID-19 Vaccine neutralize the Omicron variant (B.1.1.529 lineage) while two doses show significantly reduced neutralisation.

The data suggests that booster vaccines are a matter of urgency. The studies show that two doses may still induce protection against severe disease.

Biontech are developing an Omicron-variant-specific vaccine which could be available by March should it be needed. Pfizer do not believe that this will change their ability to develop four billion does for 2022. 

‘Mix-and-match’ approach can be used for both initial courses and boosters

Yesterday (7 December) the European Medicines Agency báo cáo that clinical studies had shown that the use of different vaccines for primary vaccination, for example,  the combination of viral vector Astra Zeneca-type vaccine and a mRNA vaccines produces good levels of antibodies against the COVID-19 virus (SARS-CoV-2) and a higher T-cell response than using the same vaccine (homologous vaccination) whether in a primary or booster regimen. The use of a viral vector vaccine as a second dose in primary vaccination schemes, or use of two different mRNA vaccines, is less well studied. The news should help with roll out, in particular where the same type of vaccine for the first dose of a two-dose vaccine is not be available. 

EMA says the data so far show that a booster dose can be taken as early as three months from the primary vaccination and that the use of a different type of vaccine could prove as good or better in terms of the immune response.

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