Some key findings include:Levels of antibodies against COVID-19 were significantly lower in asymptomatic carriers than those with symptoms during active infection. Those with asymptomatic infections tested positive for an average of five days longer than people with symptomatic infections — 19 days compared with 14 days — suggesting that they were shedding the virus longer. What was "a little bit surprising," he said, was the fact that 40 per cent of people with asymptomatic infections had no detectable antibodies at all. "This suggests that natural infection may not give long-lasting immunity, which is what people have been worried about," she said. A patient receives a shot in the first-stage safety study clinical trial of a potential vaccine for COVID-19 in March.

Source: CBC News June 28, 2020 07:15 UTC