Sweden’s capital is particularly affected by Covid-19. A study by the health authority now shows that fewer residents have developed antibodies than expected.
- The Swedish Health Department has presented the first results of a study on immunity.
- It can be seen that even in Stockholm, which was severely affected, only 7.3 percent of the residents had developed antibodies.
- It is still a long way from “herd immunity”. But that’s not the point, says epidemiologist Andres Tegnell.
Sweden is taking a special route in the fight against the coronavirus pandemic: it hopes that an increasing number of people will develop antibodies after an infection and thus establish immunity among the people. At the same time, the country is internationally in focus due to its moderate protective measures and the comparatively high number of deaths.
The Swedish health authority Folkhälsomyndigheten has now presented the results of a first test series for antibodies. They show that in the worst-affected Stockholm pandemic, only 7.3 percent of the population developed antibodies. In other parts of the country, the numbers for antibody carriers were even lower, as reported by “Dagens Nyheter” and the broadcaster SVT.
A quarter should actually be infected
These figures are below the previous calculations by the health authority and chief epidemiologist Anders Tegnell. They had expected around a quarter of Stockholm’s population to be infected or already infected at the beginning of May.
It is fundamentally unclear how many people need to be immune to the virus to stop it from spreading. So far it has been assumed that at least 60 percent of the population would have to be immune. The new study not only shows that Stockholm is still far from it. The low numbers also correspond to those from other countries, for example from Spain with only 5 percent.
According to the health authority, the results come from around 1200 samples that were taken three weeks ago.
Distance between infection and antibody formation
Chief epidemiologist Tegnell explains the difference between these initial results and his calculations in terms of the distance between the point in time of an infection and the point in time when humans develop antibodies. For example, it is currently believed that an average of 23 days prior to death had occurred.
In addition, it takes a few weeks for the body to develop sufficient antibodies to be detectable. Therefore, the Swedish Health Department said: “The numbers reflect the state of the epidemic in early April as it takes a few weeks for the body’s immune system to develop antibodies.”
“We are somewhere around 20 percent plus”
But the numbers are “not far from those of the model,” says Tegnell. “It was 7 percent at week 15, so it was a long time ago. These people were immune at week 18, which means they got sick at some point in week 14 or 15. » It is a little lower than expected, but: “It is not 7 percent now. We’re somewhere around 20 percent plus in Stockholm. »
However, it is unclear how high the immunity is after infection with the virus. According to WHO, several studies have shown that infected people do produce some antibodies that would offer “a certain amount of protection” against being infected again. However, there is still no evidence as to whether or for how long people are completely immune.
Antibodies especially in 20- to 64-year-olds
“We still don’t really know when we will reach a level that will significantly reduce the spread of infections, so we have never targeted herd immunity,” says the epidemiologist. Rather, the aim is to take measures to keep the spread of infections as low as possible. This would relieve the health system and some restrictions could be relaxed. “To make the disease go away, immunity and vaccinations have to be combined,” says Tegnell.
The study also showed which group of the population is most affected by the virus: Antibodies had mainly formed in people between the ages of 20 and 64 (6.7 percent). Antibodies over the age of 65 (2.7 percent) had the least antibodies – probably because they had followed the recommendations of the authorities and had kept their distance.
Young people up to 19 years of age had developed 4.7 percent of antibodies. Tegnell sees this as confirmed in the assumption that the virus is not widely distributed in this age group.