Coronavirus antibodies fade after only a month, a new study has revealed, in what could signal a blow to worldwide hopes of finding a vaccine.
Understanding antibody responses against Covid-19 is fundamental for the development of effective treatments and a preventive vaccine, experts say.
And if antibodies decline overtime it could suggest immunity from a potential vaccine would also fade, rendering it less effective or require boosters.
In this latest study, researchers from Nanjing University Medical School in China monitored Covid-19 antibody responses in 19 non-severe and seven severe coronavirus patients for seven weeks from disease onset.
Watch: Yahoo UK’s Health Correspondent, Alexandra Thompson explain the difference between an antigen and antibody test
They found that most patients generated antibody responses against the virus.
But only a small portion produced a potent level of antibody neutralisation activity and around one in five (20 per cent) produced no antibody response at all.
The study, published in PLOS Pathogens, also indicated that three to four weeks after hospital discharge, the neutralising activity of antibodies from recovered patients declined significantly.
The authors said: "Understanding the adaptive responses where the body makes antibodies that specifically bind to the Sars-CoV-2 among Covid-19 patients provides fundamental information for developing effective treatment and preventive vaccine."
A previous study by King's College London found 60 per cent of the 96 people studied had a “potent” Covid-19 antibody response at the height of their infection, falling to just 17 per cent three months later.
Commenting on these latest findings, Danny Altmann, professor of immunology at Imperial College London, said: "Studies like this are a vital part of the 'work-in-progress' to make sense of who has immunity and how long for…
"Once again, evidence shows that the half-life of these antibodies in the blood is not particularly sustained.”