New Omicron variant offers little protection against future infections

"The findings cast doubt on hopes that the wave of omicron that’s sweeping the world may help hasten the end of the pandemic," said Bloomberg.

With people getting fed up with pandemic-related restrictions, governments are increasingly urged globally to treat COVID-19 as endemic like influenza, which such calls given weight by vaccines becoming more accessible and coronavirus-related fatalities remaining relatively low.

According to a report by the University of California, the production of neutralising antibodies during an Omicron infection appears related to the severity of the illness.

The milder form of most Omicron cases in vaccinated people may leave those who recover from them still vulnerable to existing virus and future variants that emerge, the researchers said. 

The protection from a natural infection was about one-third that obtained through a booster shot, the study found. 

"[...] our results suggest that Omicron-induced immunity may not be sufficient to prevent infection from another, more pathogenic variant, should it emerge in the future.

They also highlight the continued importance of vaccine boosters in enhancing immunity, as breakthrough infection alone may not be reliable in eliciting protective titers against re-infection or future infection from different variants.

"Furthermore, the relative increase in immunity against the infecting variant in breakthrough infections indicates that the use of variant-specific immunogens in vaccine development remains a viable strategy for addressing variants of concern (VOCs) that continue to circulate in the population."

A new study by Danish scientists has examineed the transmission of Omicron subvariant BA.2 versus BA.1 in Danish households.

The study (pre-print available here) included 8.541 households and 17.945 household members from 20 December 2021 to 18 January 2022 and the results indicate that the rapid spread of BA.2 could be related to an inherent increased transmissibility of the subvariant. There is also evidence to support immune evasive properties of the BA.2 subvariant which is the dominant strain in Denmark.

The study found an overall secondary attack rate of 39% in BA.2 infected households compared to 29% in BA.1 infected households. The risk of being infected (susceptibility) was higher in unvaccinated persons compared with vaccinated and booster-vaccinated household members in both BA.2 and BA.1 infected households, underlining a positive effect of vaccination towards both Omicron variants.

The findings bolster work from U.K. health authorities released last week that found the omicron subvariant appears even more contagious than the original fast-spreading strain.

While BA.1 is still the most dominant type worldwide, recent trends suggest BA.2 is increasing in some countries including India, South Africa, the U.K. and Denmark, the World Health Organization said last month. 

Cover photo: Getty Images