A group of scientists in the US has identified an antibody that appears to block infection by all dominant variants of the virus that causes Covid-19, including Omicron.
The discovery could lead to more potent vaccines and new antibody-based treatments.
In a study published in the Journal of Clinical Investigation, senior author Dr Patrick Wilson from Weill Cornell Medicine at the University of Wisconsin-Madison and his colleagues, tested antibodies derived from patient blood samples against successive versions of the virus that emerged during the pandemic.
One of these proteins, dubbed S728-1157, proved highly effective at neutralising not only older variants but also seven subtypes of Omicron.
The team also had researchers from Scripps Research and the University of Chicago.
"The pandemic is winding down, but the virus is around for the long haul. If not well controlled, it could cause annual epidemics," Dr Wilson said. "This antibody and the insight it provides could help us avoid yearly surges of Covid-19 or if there is another coronavirus pandemic."
Dr Wilson's group analysed antibody-producing cells to find those that latched on to the virus's spike protein, which it uses to get into human cells.
Another study author Dr Siriruk Changrob tested the antibodies they found against 12 variants of SARS-CoV-2, including the original version of the virus.
One antibody, called S728-1157, stood out for its ability to interfere with Omicron.
Their results suggest that S728-1157 could become the basis for a much-needed alternative to conventional antibody-based treatments.
The research could also guide the design of new vaccines that rely on the spike protein to stimulate the production of antibodies, said the study.