Across Sweden, 195 laboratory-verified cases of RS virus were reported during the winter months, which is the lowest number since surveillance began 20 years ago.

This is probably because many people followed the recommendations linked to the coronavirus.

But during the summer, the Swedish Public Health Agency received indications of the spread of the RS virus outside the regular season, for example in Växjö.

- It is an unusual situation, says Anna Bärtås, pediatrician and operations manager at the pediatric clinic in Växjö, who after a winter semester completely without RS-sick children has had "a few" who had to be admitted for serious symptoms during the summer months.

A similar situation is reported from Jönköping.

In Kalmar, more positive lab responses with RS virus have been seen during the summer than the three years previously combined.

But it may be because more have been tested - the health service has not noted more RS-sick children than usual.

FHM: Follows the situation

- We have seen reports from other countries, such as parts of Australia and the USA, which had RSV epidemics in the summer when they opened up after the corona, says AnnaSara Carnahan, epidemiologist at the Swedish Public Health Agency.

AnnaSara Carnahan, epidemiologist at the Swedish Public Health Agency.

Photo: Lena Katarina Johansson / Public Health Agency

Normally, the authority collects data on RS cases from week 40 in the autumn to week 20 in the spring.

But the situation means that they have collected some data over the summer and will probably start the regular monitoring about a month earlier this year.

- There are two, three cohorts who have not had RS virus yet.

It could be a bigger epidemic than we have had in a few years, she says.

For most people, the RS virus is no more dangerous than a common cold, but for very young children and some fragile elderly people, the symptoms can become more severe.

- My concern when we open up society again is that small babies become seriously ill from RS virus, says pediatrician Anna Bärtås.