আক্রান্ত হওয়ার পর কত দিন পর্যন্ত কোভিড-১৯ এর লক্ষণ দেখা যায়?

FILE - People wearing face masks walk along the Oxford Street shopping area of central London, Oct. 20, 2021. As countries across Europe reimpose lockdowns in response to surging COVID=19 cases and deaths, the UK – long one of Europe’s hardest-hit countries -- carries on with a policy of keeping everything as normal as possible. (AP Photo/Matt Dunham, File) Source: AAP / Matt Dunham/AP