The virus (Respiratory Syncytial Virus – RSV, or more commonly referred to as RS-viruset in Swedish) usually causes minor cold-like symptoms in adults and older children, but in some cases a more serious infection can persist in the respiratory system.
Infants under the age of one, and especially under the age of six months, risk developing bronchiolitis, a blockage of small airways in the lungs which can require hospitalisation.
A seasonal increase in cases of RSV is normal, but it has begun earlier in the autumn than usual.
The trend, which has also been observed in neighbouring Norway and Denmark, has been linked to lower immunity in the population because Covid-19 measures in 2020 also reduced the spread of other seasonal infections last year.
Between the week of October 11th and the following week, the number of cases of RSV increased by 12 percent in Sweden (1,006 cases), reported Swedish news agency TT.
“If you have children younger than six months whose older siblings attend preschool, it may be wise to keep the older child home from preschool for a few weeks to reduce the risk of infecting the little sibling with RSV. We know that many babies are infected by their older siblings,” said Stockholm medical chief Elda Sparrelid in a statement on Friday.
The Västra Götaland and Uppsala regions have also urged parents to avoid sending their children to preschool if they can, avoid social gatherings and wash their hands often.
RSV is contagious and most children catch the infection at some point in the first two years of their life, but the older they get the easier it is for them to fend it off.
Common symptoms include a blocked nose, a cough, fever and wheezing. Children under six months mainly breath through their nose and may struggle to eat and drink.
If you need healthcare advice in Sweden, call 1177. In an emergency, always call 112.