KUALA LUMPUR (Oct 3): While the Covid-19 pandemic is not over, showing signs of lingering for a long time, scientists are already anticipating the next one.

In a new peer-reviewed study that appeared last week in the PLOS Pathogens science journal, researchers said SARS-CoV-2, the sarbecovirus behind Covid-19, emerged in the human population after cross-species transmission from an animal source.

They said while hundreds of sarbecoviruses have been discovered, predominantly in bats in Asia, the majority are not capable of infecting human cells.

However, Khosta-2, a sarbecovirus discovered in Russia, has been shown to interact with the same entry receptor as SARS-CoV-2.

In this study, scientists tested how well the spike proteins from these bat viruses infect human cells under different conditions.

They found that the spike from 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 against SARS-CoV-2.

The researchers said what differentiates Khosta-2 is that, like SARS-CoV-2, it can also infect people — in lab conditions.

They added that what makes Khosta-2 particularly dangerous is that it appears to shrug off the antibodies that currently work against SARS-CoV-2, also in lab conditions.

The peer-reviewed study said that in late 2020, two Clade 3 sarbecoviruses were identified in Rhinolophus bats in Russia: Khosta-1 was found in Rhinolophus ferrumequinum and Khosta-2 in Rhinolophus hipposideros.

It said similar to other European and African Clade 3 viruses, the Khosta viruses are divergent from the receptor binding domain (RBD) found in SARS-CoV-1 and -2.

“Here, we confirm angiotensin-converting enzyme 2 receptor preference in these and other Clade 3 viruses using pseudotyped virus-like particles with both chimeric and full-length Clade 3 spikes.

“We also assessed the antibody neutralisation of a chimeric SARS-CoV-2 spike encoding for the RBD from the Khosta-2 virus to assess the protection offered by current SARS-CoV-2 vaccines against future sarbecovirus threats. Critically, our findings highlight the urgent need to continue development of new and broader-protecting sarbecovirus vaccines,” said the researchers.