Individuals infected with coronavirus are unlikely to catch the illness again for at least six months, researchers at the University of Oxford said Friday.
The finding comes as part of a large-scale study into Covid-19 reinfection after observations from healthcare professionals that the phenomenon was relatively rare.
Oxford University Professor David Eyre, one of the authors of the study, said the findings were "really good news".
The Oxford study was released as a series of advances are made public on a number of potential coronavirus vaccines.
US biotech firm Moderna said its vaccine candidate was nearly 95 percent effective in a trial and Pfizer, with its German partner BioNTech.had similar results on its product.
The UK's leading Covid-19 vaccine trial, a collaboration between Oxford University and AstraZeneca, showed that the elderly tolerated its shot better than younger adults.
Findings from the second phase of the trials, published in The Lancet medical journal, showed that the vaccine was “safe and provokes immune response”.
"We can be confident that, at least in the short term, most people who get Covid-19 won't get it again," Prof Eyre said.
The authors highlighted they had not yet gathered enough data to make a judgement on reinfection after six months.
However, the ongoing study has an end goal of verifying how long protection from reinfection lasts in total.
The director of infection prevention and control at study partners Oxford University Hospitals (OUH), Katie Jeffery, called the finding "exciting".
It indicated "that infection with the virus provides at least short-term protection from re-infection", she added.
The Oxford study drew on data from regular coronavirus testing of 12,180 health care workers at OUH over a period of 30 weeks.
It found that none of the 1,246 staff with coronavirus antibodies developed a symptomatic infection.
Three members of staff with antibodies did test positive for the virus that causes Covid-19 but were all well and did not develop symptoms.