US-based researchers have identified a vulnerability at the root of COVID-19 that could "plausibly succeed in neutralising the virus".
The scientists, from Scripps Research Institute in California, believe the discovery could also be key in protecting against coronaviruses that crop up in the future.
The vulnerability was identified after analysing an antibody recovered from a SARS patient in the early 2000s, says their study, published in the journal Science.
Scripps researchers found that the antibody - which bound to the SARS-CoV virus that caused the patient to be infected with SARS - is also able to bind with SARS-CoV-2, which causes the new coronavirus.
Structural mapping of SARS-CoV and SARS-CoV-2 suggests a "functionally important and vulnerable site" on coronaviruses that allow this particular antibody to bind, the study's authors say.
"The knowledge of conserved sites like this can aid in structure-based design of vaccines and therapeutics against SARS-CoV-2, and these would also protect against other coronaviruses - including those that may emerge in the future,” says senior author Dr Ian Wilson.
The research institute is hopeful these "neutralising antibodies, if developed into therapies, could be used to treat COVID-19 patients and to provide temporary protection from the virus to uninfected individuals, for example healthcare workers".
COVID-19 is significantly more infectious than its coronavirus predecessor SARS. The latter disease infected 8000 people and killed almost 800 after emerging in 2002, but was soon eradicated.
In contrast, COVID-19 has already infected 1.3 million people and resulted in the deaths of 75,000 around the world.
However Scripps is hopeful its latest breakthrough could be a major boon in the race to find a vaccine for COVID-19.
"Our ultimate goal here is to obtain structural information on antibodies and their binding sites, and use that to guide SARS-CoV-2 vaccine design, just as our lab has done with influenza and HIV," study co-author Dr Nicholas Wu said.
Scripps is hopeful there are other antibodies that are even more effective at binding with coronaviruses, and is encouraging those who have recovered from COVID-19 to send antibodies, via blood donations, to their lab.