J&J, Sinopharm, Sputnik V Covid-19 shots less effective against Omicron: study

‘Moderna, AstraZeneca, Pfizer retained activity against new variant but antibody response greatly reduced’

Covid-19 vaccines from US drugmaker Johnson & Johnson and China's Sinopharm as well as Russia's Sputnik V shot had no neutralising activity against the Omicron variant, according to a study which has not yet been peer reviewed.

The study – conducted by Humabs Biomed SA, a unit of Vir Biotechnology, and the University of Washington, among others – compared the activity of some widely-used Covid-19 vaccines and treatments against Omicron and against the original virus strain first detected in China.

Vaccines from Moderna, AstraZeneca, Pfizer and partner BioNTech retained activity against Omicron, but the antibody response was greatly reduced when compared with the original strain, the study found.

It also found the decrease was less pronounced for vaccinated individuals who were previously infected.

Russia's Gamaleya Center issued a statement saying that the Sputnik V shot was tested "deliberately using serum samples that are not representative" and thus, conclusions about its effectiveness against the Omicron variant based on the study could not be made.

Also read: Omicron spreads faster and weakens jabs: WHO

The Russian Direct Investment Fund said on Friday that the vaccine induces a "robust neutralising" antibody response to the Omicron variant, citing a preliminary lab study by the Gamaleya Center.

Humabs Biomed's study also found that while the effectiveness of GlaxoSmithKline and Vir Biotech's Covid-19 drug sotrovimab reduced three-fold against Omicron compared to the original strain, monoclonal antibody treatments by Regeneron and Eli Lilly completely lost their neutralising activity against the variant.

The finding is consistent with recent laboratory tests demonstrating the two treatments lose most of their effectiveness when exposed to the Omicron variant.

In a real-world study published this week, it was seen that Pfizer-BioNTech's Covid-19 vaccine has been less effective in South Africa at keeping people infected with the virus out of hospital since the Omicron variant emerged last month.