Italy was the first country outside China to suffer a major outbreak of coronavirus and remains one of the worst hit, with almost 70,000 reported deaths so far.
South Africa said on Friday a virus strain similar to the one reported in the United Kingdom was driving a second wave in the country, prompting some countries to include South Africa in their travel bans.
The total number of confirmed cases in Switzerland and neighbouring principality Liechtenstein increased to 403,989, the death toll rose by 120 to 6,003, and 184 new hospitalisations kept pressure on the health care system.
But the wooden ship has been docked after new measures to stem a fourth wave of the coronavirus were introduced earlier this month, threatening the city's last remaining antique junk.
The sero-prevalence study, presented late on Tuesday, is now in its fourth round. Its work involved carrying out rapid antibody tests on 51,409 people across the country of some 47 million people between November 16 and 29.