Astrazeneca & Covishield Booster 75% Effective Against Omicron COVID Variant: UK Study

Two doses of the COVID-19 vaccination might not have been “completely effective” in offering total protection during the hypervirulent Delta variant wave, so, therefore, scientists now say that an additional third booster jab might mitigate the severity of B.1.1.529 Omicron variant, reducing the disease symptoms by 75%. Scientists in the UK  found that the COVID-19 booster shots delivered 71% to 75% protection against the mild symptoms from the Omicron variant, a statement by the UK Health Security Agency (UKHSA) stated, Friday, Dec. 10. It added that currently, the 2-shot regime of the vaccines could be less effective against the heavily mutated B.1.1.529 strain.  

In its latest technical briefing, the agency, as per PTI, stated that two doses of both the Oxford/AstraZeneca and Pfizer/BioNtech vaccines gives "much lower levels" of protection against symptomatic infection compared to the Delta variant. It is to mention that the Oxford/AstraZeneca vaccine is administered in India as Covishield. However, the third booster dose does seem to boost immunity against Omicron, based on an analysis of data from 581 new variant cases.

Omicron transmitting 'more effectively' than Delta, UK to exceed 1 mn infections in Dec

The key findings were made after at a latest variant technical briefing in the UK, it was revealed that Omicron continues to grow rapidly across all regions of England as was established by the sudden surge in the COVID-19 confirmed cases and S gene target failure (SGTF). Although, in a positive development, none of the patients to date have been known to have been hospitalised or died from the highly mutated strain, as was in the case of Delta. The studies and research, however, have revealed that Omicron is transmitting more effectively than Delta. And as WHO earlier at a briefing stressed that the variant spread may be in the early stages and its impact is not yet fully understood. 

“The UK Health Security Agency (UKHSA) estimates that if Omicron continues to grow at the present rate, the variant will become the dominant strain, accounting for more than 50% of all COVID-19 infections in the UK by mid-December,” the latest update from the UK government read on Dec. 10.

“It is projected that if current trends continue unchanged, the UK will exceed one million infections by the end of this month.” 

“The early observations for 2 doses of AstraZeneca are particularly likely to be unreliable as they are based on small numbers and are likely to reflect an older population and a population with more comorbidities than those given the Pfizer vaccine,” the British government’s Health Security Agency (UKHSA) stressed. It went on to add that AstraZeneca was the main vaccine used early in during vaccine campaigns for the care homes and in clinical risk groups. “These groups have been prioritised for booster doses since the start of the rollout in September to increase their protection,” the British government informed. Vaccine’s accurate effectiveness against severe disease from Omicron variant of the novel coronavirus is not yet known but the booster is expected to give significantly higher protection against symptomatic disease, it added.