Existing vaccines effective against severe Omicron, study suggests
Findings could help health authorities decide whether switch to variant-targeted jabs is necessary
Cellular immunity elicited by the BioNTech/Pfizer and Johnson & Johnson Covid-19 vaccines is effective against the Omicron coronavirus variant, according to a study, suggesting vaccines will protect against severe disease even if the antibody responses against the strain are not as strong or durable.
The findings, contained in a new Harvard medical school study, add to evidence that the current vaccines hold up against severe Covid outcomes, and could help health authorities to decide whether to switch to Omicron-targeted jabs.
“These data suggest that current vaccines may provide considerable protection against severe disease with the Sars-Cov-2 Omicron variant despite the substantial reduction of neutralising antibody responses,” the researchers wrote in the study made public on Monday. The paper has not been peer-reviewed yet.
Previous evidence suggests that the existing vaccines lose antibody power when pitted against Omicron, meaning individuals are likely to get infected and develop mild disease when they come into contact with the virus.
A third shot at least partially restores that antibody protection, and countries have been racing to scale up their booster programmes to avoid new restrictions. But vaccines are still expected to protect against severe disease, and health authorities have said they would closely examine evidence such as the one contained in the Monday study to decide whether a switch to Omicron-targeted vaccines is necessary.
Cellular immunity is a different part of the immune response that tends to last longer than antibodies.
While manufacturing projections for 2022 indicate supply will keep up with demand in most scenarios if the world continues to use the shots available at present, switching to Omicron-targeted vaccines could see a global supply squeeze.
Healthcare analytics company Airfinity has estimated — in a best-case scenario — that if all drugmakers switched production and scaled up quickly, 6bn Omicron-targeted shots would be available by October 2022. If drugmakers were to switch half of their production and continued to make both versions, that target would not be reached before January next year.
Health authorities sounded the alarm on the highly mutated Omicron variant late last year, saying it was able to pierce through immunity afforded by previous vaccines or infection, but scientists have been hopeful widely used shots could still protect from severe disease.
Early findings suggest Omicron appears to be milder than previous variants, but it is not clear yet if this is because of the variant itself, or because most of the world has either been infected or vaccinated, or a combination of the two factors.
However, scientists have said that its high transmissibility, coupled with uneven vaccine coverage, could still mean health systems worldwide come under pressure as many more people get infected.
The World Health Organization has repeatedly called for more equitable distribution of vaccines. It set a target of 70 per cent coverage in all nations by mid-2022 after about half of its member states were unable to hit the 40 per cent milestone in 2021. The health body said the failure to meet targets was largely due to severe undersupply.