Next strain of COVID-19 may be more dangerous - lab study

According to a Sunday report by Bloomberg, a South African laboratory study using Covid-19 samples from an immunosupressed individual, a person infected with HIV, over six months showed that the virus evolved to become more pathogenic, indicating that a new variant could cause more illness than the current predominant omicron strain.

Over the six months, the virus initially showed the same levels of cell fusion and mortality as the omicron BA.1 variant, but its mutation increased these levels to become similar to the first variant of Covid-19 identified in Wuhan, China.

The results indicate that the Covid-19 pathogen may mutate further and a new variant could cause more severe illness and deaths than the relatively mild omicron strain. The study, which suggests that not only a milder (see omicron) but also a more severe variant of Covid-19 may be more viable than the previous strain, has not yet been peer-reviewed.

The US Centers for Disease Control and Prevention (CDC) on Friday estimated that BQ.1 and BQ.1.1 are causing 57% of new infections in the U.S., and the omicron BA.5 subvariant, once dominant, now makes up only a fifth of new Covid cases.

The BQ subvariants are more immune evasive and likely resistant to key antibody medications, such as Evusheld and bebtelovimab, used by people with compromised immune systems, according to the National Institutes of Health. This includes organ transplant and cancer chemotherapy patients.

Hungarian virologist Gábor Kemenesi wrote at the end of October that a significant change in the coronavirus landscape was the now visible emergence and spread of recombinant variants of the virus. This simply means that different variants are mixing at the gene level and are also evolving towards the aforementioned properties (avoiding immunity, better spread, etc.). He says we have reached the stage in the pandemic where several variants are spreading in parallel around the world and mutating in very similar directions (what researchers call convergent evolution).

"This broadly suggests that the virus is having very similar effects everywhere, probably due to the fact that most of the world already has some form of acquired immunity - either vaccinated, or encountered the virus, or both. Several variants of the virus, which have emerged and are spreading in parallel, are trying to trick the immunity they have developed by picking up similar mutations, at least at the antibody level - in effect making it easier to 'catch it again'," he explained.

Variants of concern: Omicron

It was 26 November 2021 that the World Health Organization (WHO) declared that the world was facing a new variant of concern: Omicron. It would go on to change the trajectory of the COVID-19 pandemic.

Omicron was quickly identified as being significantly more transmissible than Delta, the preceding variant of concern. Within 4 weeks, as the Omicron wave travelled around the world, it replaced Delta as the dominant variant.

Countries which had so far been successful in keeping COVID-19 at bay through public health and social measures now found themselves struggling. For individuals, the greatest price was paid by those who were at risk of severe disease but not vaccinated, and we saw hospitalizations and deaths rise in a number of places around the world, the WHO said in a recent report.

This graph shows reported COVID-19 cases in grey and deaths in blue; the impact of Omicron is clear. While Omicron was less severe compared to Delta, there were still a significant number of deaths due to this variant worldwide. The recent decline in COVID-19 testing around the world has meant that we are underestimating the true number cases, now more than ever.

By March 2022, WHO and partners estimate that almost 90% of the global population had antibodies against the COVID-19 virus, whether through vaccination or infection. Overall, though, this new variant caused less severe disease than Delta on average. 

The next variant of concern?

Since the emergence of Omicron, the virus has continued to evolve. Today, there are over 500 sublineages of this variant circulating, but not one has been designated as a new variant of concern.

So far, these sublineages of Omicron have much in common:

• they are all highly transmissible,
• replicate in the upper respiratory tract and
• tend to cause less severe disease compared to previous variants of concern, and
• they all have mutations that make them escape built-up immunity more easily.

This means that they are similar in their impact on public health, and the response that is needed to deal with them.

If the virus were to change significantly – like if a new variant caused more severe disease, or if vaccines no longer prevented severe disease and death – the world would need to reconsider its response. In that case, we would have a new variant of concern, and with it, new recommendations and strategy from WHO.

The WHO noted that testing and sequencing are declining globally and the sequences that are available aren’t globally representative (most sequences are shared from high-income countries). Hungarian authorities, for instance, have not published testing data since mid-May this year.

WHO and partners also remain concerned that surveillance at the human-animal interface is limited, where the next variant of concern could come from.

Cover photo: Getty Images