COVID-19 vaccines may be ineffective against Omicron without booster dose, suggests US study

A new US story released on Tuesday (December 14) found out that all the three COVID-19 vaccines currently authorised to use in the country appeared to be significantly less effective against the new Omicron variant. However, the study adds that a booster shot will be likely to restore most of the protection.

The alarming study saw researchers from Harvard, MIT and Massachusetts General Hospital (MGH) took blood samples from people who had been administered the Pfizer/BioNTech, Moderna and Johnson & Johnson vaccines and tested the immunity against a pseudo-virus which was engineered to resemble the Omicron COVID-19 strain. The study hasn’t been peer reviewed till now.

The study found that antibody neutralisation for the Omicron variant was “low to absent” across samples for all three vaccines. While Moderna and Pfizer/BioNTech vaccines are administered as a two-dose inoculation, J&J is a single-dose vaccine.

On the other hand, the study found that samples from people who had received a booster dose showed potent antibody neutralising for Omicron.

The researchers also suggest that the new variant of concern is more infectious than the previous COVID-19 variants. Omicron appears to be twice as transmissible as the Delta variant, which currently dominates infections around the world but may soon be taken over.

The study is in line with another study, by the University of Oxford, which found that the Pfizer and the AstraZeneca vaccines do not induce the required neutralising antibodies against Omicron.

(With inputs from agencies.)