Experts have warned a lack of testing infrastructure worldwide means the global case number is probably much higher than is being reported, particularly in poorer countries.
On 31 March, the city reported 4144 new asymptomatic cases and 358 new symptomatic cases, compared with 5298 asymptomatic cases and 355 symptomatic cases the day before.
All the participants were assessed five months later, while a third 33 per cent were also assessed one year post-discharge.
Nearly two-thirds of people who were restricted from visiting relatives while they were hospitalised with covid-19 may have developed a stress-related disorder.
Other coronavirus news Covid-19 vaccines are being rolled out for 5- to 11-year-olds in England.
Officials now plan to lift some restrictions in areas that have not had any positive cases for two consecutive weeks.