Scientists have found that a coronavirus discovered in bats in Russia is able to infect humans and evade vaccines and available antibody treatments.
This virus belongs to the same group of viruses that SARS-CoV-2, the virus that causes Covid-19 disease, belongs to.
The findings have led the scientists to call for a vaccine that covers a broader range of coronaviruses as opposed to the ones that only cover SARS-CoV-2 or its specific variants and sub-variants. The idea is that while vaccine-evading variants such as Omicron could be targeted with specific vaccines, a vaccine that provides general protection against a range of coronaviruses is also essential.
Here we explain the findings of coronaviruses found in Russia, how these viruses work, and the need for vaccines offering broader protection.
Two coronaviruses found in bats in Russia
Two coronaviruses were found in bats in Western Russia in late 2020: Khosta-1 and Khosta-2. Bats are known to be reservoirs of several viruses.
Before going further, it may be noted that there are hundreds of coronaviruses in the nature, ranging from those which do not affect humans to those which cause common cold. Viruses like SARS-CoV-2, SARS, or MERS are only some of the few coronaviruses that endanger human lives.
Of these two viruses, Khosta-2 can infect humans, evade vaccine-derived protection, and bypass monoclonal antibody treatments, according to American experts' study published in PLOS Pathogens earlier this month.
Simply speaking, Khosta-1 virus cannot be neutralised by currently available medical options.
When combined with serum from people who have been vaccinated against Covid-19 with Khosta-2, the antibodies in the serum did not neutralise it and similar results were obtained when serum from people having recovered from Omicron infections was combined with Khosta-2, reported Time magazine.
How the new virus works?
Khosta-2 virus can infect in humans just like SARS-CoV-2, using its spikes to enter and infect human cells.
The spike of Khosta-2 latches on to the ACE-2 receptor of human cells and infects it. This is how SARS-CoV-2 infects human cells.
"We found that the spike from virus, Khosta-2, could infect cells similar to human pathogens using the same entry mechanisms, but was resistant to neutralisation by serum from individuals who had been vaccinated for SARS-CoV-2," study authors summarised their findings.
Notably, this virus is not yet known to have infected humans. It is only in the laboratory setting that it has been learnt that a human infection is possible.
What are the concerns?
While there are no immediate concerns since the virus is not known to have infected humans on its own, scientists are concerned about the possibility of such a spill over — a spill over means a virus jumping from one specie into another.
If Khosta-2 or some similar virus ends up infecting humans naturally, then it would definitely be a cause for concerns as we don't have medical options against it.
Moreover, there is also the risk of 'recombination' of Khosta-2 with other viruses, which can produce a dangerous version of the virus. Recombination refers to the interaction of one virus with another which results in the creation of another virus. It can be a new virus or a variant or a sub-variant of any of the parent viruses as well.
"When you see SARS-2 has this ability to spill back from humans and into wildlife, and then there are other viruses like Khosta-2 waiting in those animals with these properties we really don’t want them to have, it sets up this scenario where you keep rolling the dice until they combine to make a potentially riskier virus," said Michael Letko of Washington State University (WSU), the lead author of the study.
The Time magazine further noted, "It’s a sobering reminder that pathogens are ready and waiting to jump from any number of animal species into humans. And in many cases, as with SARS-CoV-2, these microbes will be new to people and therefore encounter little resistance in the form of immunity against them."
The call for pan-coronavirus vaccines
The findings regarding Khosta-1 have led to renewed calls for a pan-coronavirus vaccine which covers a broader range of coronaviruses.
Derek Lowe in Science noted that there are four broad groups of coronaviruses:
1. Embecoviruses, which have some common-cold viruses
2. Sarbecoviruses, are the SARS and SARS-CoV-2 viruses and their variations thereof
3. Merbecoviruses, which caused the MERS outbreak in humans
The Khosta-2 belongs to the sarbecoviruses group of coronaviruses.
Scientists have broadly called for two types of pan-coronavirus vaccines, one that covers all the groups of coronaviruses and one that covers all viruses within the sarbecoviruses group — which contains the most lethal coronaviruses, notes Derek.
There are currently two vaccines under development that cover all the viruses in the sarbecoviruses group. While one developed by the US military is in the clinical trials, the second is yet to enter clinial trials.
If a vaccine effective against the sarbecoviruses group is developed, then it would mean that just one vaccine would provide protection against multiple viruses —and thus multiple disesses— such as SARS, SARS-CoV-2, and Khosta-2.
WSU's Letko, cited above, said, "Unfortunately, many of our current vaccines are designed to specific viruses we know infect human cells or those that seem to pose the biggest risk to infect us. But that is a list that’s everchanging. We need to broaden the design of these vaccines to protect against all sarbecoviruses."
The current timeline for such a virus is 2024 at the earliest. One of the two vaccines, mentioned above, is also supported by the Government of India and Bill and Melinda Gates Foundation, among others. It's being developed by a company named DIOSynVax. Moderna, one of the first to make the mRNA vaccinea for SARS-CoV-2, has also started working for a pan-coronavirus vaccine. Donors have also recognised the importance of this.
The BBC reported that DIOSynVax has received a $42 million grant by Coalition for Epidemic Preparedness Innovations (CEPI), which is backed by Bill and Melinda Gates, the Indian and Norwegian governments, and the World Economic Forum, among others.
"Money is being thrown at the target in unprecedented sums. CEPI have allocated an initial budget of around $200m (£169m/€193m), with the NIH adding an additional $36m (£30m/€35m) to the pot. Buoyed by their success in developing one of the first Covid-19 vaccines, Moderna has recently entered the fray, announcing their intention to produce a vaccine which could protect against all four coronaviruses that cause the common cold," reported BBC.