The case of Sweden has tempted some governments to consider Sweden’s mild strategy, which has not imposed quarantine, but scientists warn that it is a risky one, given that population immunity is an unresolved issue of the pandemic. Britain seems to be shaping its response to Sweden: despite record increases in the number of infections, Prime Minister Boris Johnson has relied more on personal responsibility than on restrictions. Among the latest measures was the closing of pubs, bars and restaurants at 10 a.m. – however, people are served indoors, where queues form and they crowd into small spaces.

In Sweden, on the other hand, no restrictions are usually imposed on the population by law, people have been urged to keep their social distance and wash their hands, while restaurants have remained open, as have schools for those under 16. .

However, Sweden acknowledged that its approach had a vulnerability, which led to a high mortality rate for a country with a population of 10 million people: more than 5,800 people died, half in nursing homes alone.

British Foreign Minister Dominic Raab wanted to clarify that the new British measures do not follow the model of Sweden. However, a British government official confirmed to CNN that Prime Minister Johnson had received advice from Sweden’s pandemic response architect, expert Anders Tegnell, two days before new measures were introduced.

“The prime minister examined a wide range of scientific opinions over the past weekend – on Sunday he listened to several scientists and used the evidence provided to formulate his package of measures. It was an opportunity for more people to give advice, “he said.

Swedish officials have warned that Sweden is not out of danger, although the epidemic appears to be under control after spring and summer deaths and an infection rate of about 38 cases per 100,000 population. By comparison, the United Kingdom has 87 and Spain 320.

However, in the last week a slight increase in the number of infections has led Tegnell, the epidemiologist who advises the government, to admit that Sweden may also need a little stricter measures at the local level and to recommend wearing a mask in public places. Swedish Prime Minister Stefan Löfven has also expressed concern about the rise in infections.

The Swedish Public Health Directorate denied that it would be a change of strategy insofar as it was always willing to recommend masks and take action in certain situations.

Interest in Sweden has marked a resurgence in the debate over herd immunity, which suggests that the acquisition of immunity by the healthy population can stop the spread of the virus until the epidemic is extinguished. But the percentage should be 60 or 70% – a large figure that is usually obtained only by immunization.

Only 15% of the stockhom population has antibodies to coronavirus

However, research consisting of antibody tests has shown that even the population of Stockholm, one of the hardest hit cities, has an immunity of only about 15%. By comparison, less than 10% of Americans tested positive for antibodies, far from herd immunity, while the protection they provide is unknown.

Although at the height of the pandemic, discussions focused on antibodies, researchers are also examining the role of T lymphocytes, which the body naturally engages in the fight against infections.

In this regard, a study by researchers at the Karolinska Institute in Sweden showed that people who remain healthy have a higher level of T cell reaction than would be expected. They compared samples from asymptomatic or mild forms of COVID-19 with healthy donors. Surprisingly, immune responses of T lymphocytes to the virus were observed in 30% of healthy blood donors – that is, twice as much immunity as people who were cured of COVID-19 and developed antibodies.

This could mean that the population actually has a higher degree of immunity than expected, although scientists do not know for sure. Immunologist Cecilia Söderberg-Nauclér, who works at the same institute but did not contribute to the study, said that immune reactions to the virus do not show that the person has immunity to SARS-CoV-2 infection.

In addition, these results are not arguments for measures such as herd immunity, and the government could not act on them for two reasons: it is not certain that previous infection with the new coronavirus underlies immune reactions and other pre-pandemic studies have showed the existence of T reactions in between 40 and 60% of healthy blood donors, suggesting that other viral infections were probably the basis and even the acquisition of a certain degree of immunity.

“There are indications that this is something present in the population before this virus, and the question is: does it help us now?” She told CNN.

The researcher explained that these lymphocytes are like “soldiers trained” previously by other infections and that they act in the face of an identical or similar threat.

“This is what happens in laboratory tests – you trigger responses and then get them to fight SARS-CoV-2, but they may already be caused by other infections. That is why there are arguments in favor of the hypothesis that we have cross-immunity. But is it also protective? We do not know”.

On the other hand, if the virus were allowed to circulate freely, some people could be affected by the disease in the long run.

“We know that at least 10% of people suffer from long-term consequences of the disease and even five or six months after infection they cannot get out of bed. I can’t work at work, I can’t work at school, Söderberg-Nauclér said.

Factor X

Until concrete evidence emerges that Sweden’s population is developing immunity, it is not known why it has such low rates of infection.

Factors related to Swedish society can be an explanation. More than 50% of Swedes live alone – a statistic that exceeds European figures. It could be a significant factor insofar as studies have shown that most people get the virus from those they live with. In addition, Swedish cities do not have a high population density, such as the United Kingdom and the United States, although this factor is not yet well understood.

Then Sweden has strong social protection programs – people with cold symptoms, regardless of their profession, are urged to stay home for two weeks and receive their full salary.

Other experts have warned that implementing the Swedish model in the UK, which works differently and is a different culture, is risky.

“We see no value in praising Sweden’s example,” said Gabriel Scully, who is part of an independent group of SAGE (emergency scientific advisory agency) experts offering an alternative to the official SAGE government group. He described the Swedish strategy as “inefficient” compared to northern neighbors such as Finland and Norway.

The group said the UK was more vulnerable to the virus than Sweden – where housing bills are higher and unemployment benefits lower, so people are more likely to take risks. A factor in more severe infections is pollution, and the two countries also differ in the average number of students in a class: 27 in the UK compared to 20 in Sweden.

The Swedes are even more compliant, generally trusting the authorities. According to government data, more than 80% of Swedes respect social distance and health safety measures, while 60% of them have reduced their outings in public places.

Professor John Edmunds, one of the British government’s pandemic advisers, told Sky News that the measures recently announced by Johnson are as dangerous as a truck driving up a hill, but Sweden also has valuable lessons.

“We can learn a lot from Sweden, from the benefits of a consistent long-term strategy and consistent messages to assisting people in making beneficial choices,” he told CNN.

Sweden has reached 90,923 cases of infections. The largest number of new daily infections was recorded on July 24, at 1,698. On September 23, Sweden reported 554 new infections, the most daily cases of the month so far.