Herd immunity still 'a long way off' in Sweden
Just 7.3% of those in Swedish's capital Stockholm had developed COVID-19 antibodies by late April, according to a study
The findings have fuelled concerns that a decision not to lockdown the country against the pandemic may bring little herd immunity in the near future.
The strategy was championed by Sweden's chief epidemiologist Dr Anders Tegnell.
He recommended voluntary measures against the virus, rather than a mandatory lockdown like those imposed by many