Sweden’s hopes of achieving herd immunity to combat coronavirus has received a fresh blow with a study showing fewer citizens than anticipated have developed antibodies to the virus.

The country has opted for a more liberal strategy to manage the pandemic – keeping most schools, restaurants, bars and businesses open, as much of Europe hunkered down behind closed doors.

Swedish health agency officials have stressed that herd immunity is not a goal in itself and is only being used to slow the virus enough for health services to cope, not suppress it altogether.

However, the study, the most comprehensive yet, showed only around 6.1% of Swedes had developed antibodies, well below levels deemed enough to achieve even partial herd immunity.