Recovered coronavirus patients who developed infection-fighting antibodies will usually start to lose them after one month, a new study reveals.
This means it’s possible for people who were once sick with the virus to be reinfected.
But the discovery isn’t necessarily bad news, according to the study’s authors at China’s Nanjing University Medical School.
Analysing antibody responses in COVID-19 patients could help researchers develop an effective vaccine, they said.
In their study, published on Thursday, researchers closely monitored SARS-CoV-2-specific antibody responses in 19 non-severe and seven severe COVID-19 patients for seven weeks from the time they fell ill.
They found most patients generated antibody responses against the coronavirus, including three parts of the virus’s dangerous spike protein that infects us by latching onto human cells.
More than 80 per cent of recovered COVID-19 patients had developed antibodies, the study found.
But only a small portion of patients generated ones that were truly powerful against infection.
The researchers said their findings highlighted the need for doctors to carefully select blood samples from recovered patients by testing their antibodies before transfusing them into other COVID-19 patients.
“Three to four weeks after hospital discharge, the neutralising (sic) activity of antibodies from recovered patients declined significantly, suggesting that recovered COVID-19 patients might be susceptible to reinfection with SARS-CoV-2,” the authors wrote.
“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.”