DNA Explainer: How effective are COVID-19 vaccines against Omicron?

The Omicron variant could reduce the effectiveness of certain COVID-19 vaccines, according to new research. A latest study by the University of Oxford has found that vaccine protection in the Omicron variant is less than that of the Delta variant.

Blood samples collected from people vaccinated with two different COVID-19 shots and tested against the new strain showed a substantial drop in neutralising antibodies which is a proxy for protection against the virus. In a paper submitted on Monday, the researchers observed that this substantial drop in neutralising antibodies is particularly less in comparison with that of the Delta variant. 

The study found that Omicron lessened the Pfizer vaccine's protectiveness after two doses. Studies of other COVID-19 vaccines from Moderna, AstraZeneca and Johnson & Johnson are also underway. The researchers saw a roughly 30-fold drop in neutralising antibodies against Omicron after two doses of the Pfizer vaccine compared with the Delta strain. The impact on the Astra shot was similar. 

The study also revealed evidence of some participants failing to neutralize the virus at all. Some scientists now suspect that the Omicron variant could become the dominant strain of COVID-19, replacing the Delta variant. Delta currently makes up 99.8% of global COVID-19 cases according to WHO.

Besides neutralising antibodies, scientists are also looking at how T cells respond to the variant, with data expected in the coming weeks. The Oxford study results also echo other recent findings that emphasize the need for booster shots, especially amid preliminary evidence on the Omicron variant which suggests higher transmissibility meaning it can spread faster than other variants. 

The scientists however are yet to find whether the existing vaccines have the ability to ward off severe disease. Meanwhile, the World Health Organisation (WHO) Regional Director for Southeast Asia, Dr Poonam Khetrapal told an Indian media that, "While studies are going on, in view of multiple mutations in Omicron, it is reasonable to assume that the current vaccines offer protection against severe diseases and death."

Data is also not available yet on how Omicron affects children. It has been noted that Omicron cases are also being reported among those vaccinated. Experts are of the opinion that vaccines prevent chances of being infected but they cannot completely protect from the virus. And this holds true for all variants.