Sweden's Coronavirus Herd Immunity 'Nowhere in Sight,' Researchers Say

Sweden, which has made headlines during the COVID-19 pandemic for not locking down like other countries, is nowhere near achieving herd immunity, according to researchers.

The country didn't enforce a lockdown to prevent the spread of the coronavirus, but instead advised citizens on how to behave. Shops, restaurants, and gyms stayed open, but schools and universities closed to over-16s, and large-scale gatherings of more than 50 people were banned. Over-70s and those with COVID-19 symptoms were told to self-isolate.

The country harnessed its concept of folkvett, or the common sense of the people as a collective, to try to combat the disease, professor David Goldsmith, a retired physician, and Eric Orlowski of the department of anthropology at the University College London, wrote in a commentary in the Journal of the Royal Society of Medicine. The commentary was titled "Four months into the COVID-19 pandemic, Sweden's prized herd immunity is nowhere in sight."

The government hoped allowing the virus to spread in the population would lead to herd immunity. This is where enough people in a population are immune to a virus, stopping it from spreading. This can be achieved with vaccines or through natural infections, the authors said.

Evidence suggests that being infected with the COVID-19-causing coronavirus can trigger the production of antibodies, although it's unclear whether this protects against reinfections, the authors noted. While it was hoped that 40 percent of the population of Sweden's capital Stockholm would be carrying antibodies against the virus by May 2020, the figure was in fact around 15 percent.

Goldsmith told Newsweek the pair worked this out by bringing together available evidence on the topic as of late June 2020, including from antibody studies from academic centers, and governmental or health organizations such as the Swedish Health Ministry. He noted not all of the surveys had been formally peer-reviewed.

Compared with Denmark, Finland and Norway, the rates of infection, hospitalization, and death per million population were "much" higher in Sweden, according to evidence cited by the authors. In addition, infections and death remained persistent, the pair said, beyond that seen during critical weeks in Denmark, Finland and Norway. Their "rapid lockdown measures seem to have been initially more successful in curtailing the infection surge," they said.

Concluding, they wrote: "Only once we can fully understand both the pandemic and the impact of the measures that were taken—after 1–2 years at least—can we then begin fairly to judge what was done correctly."

Simon Clarke, associate professor of cellular microbiology at the U.K.'s University of Reading, who also did not work on the commentary, said in a statement natural herd immunity may have been an appealing notion to some because of the lack of a lockdown or curbs on people's freedoms, "but it was nothing more than an idea which lacked supporting data."

"The Swedish experience of attempting to achieve this, compared to other Nordic countries' responses, resulted in much higher numbers of infections and deaths per capita, in addition to a prolonged outbreak. Moreover, far fewer Swedes than predicted generated antibodies to the coronavirus, suggesting the strategy failed to generate widespread protective immunity.

"These findings should prove a salutary warning, that appealing concepts and theories require supporting data when people's lives are at stake and should not be used to fit preconceived narratives."

Julian Tang, honorary associate professor in respiratory Sciences at the U.K.'s University of Leicester who was not involved in the commentary, said in a written statement the report was interesting but the data was "a bit patchy."

Tang said: "Maybe that was all that was available for data-mining at the time of writing this article."

The title "may not be entirely accurate and a bit premature because we have not seen and compared the updated seropositivity rates for June/July 2020 across these same locations, at least from what I can see presented in the paper."