The Swedish Public Health Agency is investigating several cases of influenza B that have resulted in severe complications, such as myocarditis and encephalitis, in minors with no previous illness or underlying conditions. Authorities have issued an official statement urging sick people with respiratory symptoms to stay home and avoid close contact with others.
The Swedish government has decided to launch an investigation to assess whether there are more cases of influenza B with severe complications than expected and whether there is any other common contributing cause other than influenza infection. Other infection control units have been asked to investigate whether there are similar cases in other regions of the territory. Virological analyses have revealed that all influenza B strains characterized in Sweden belong to the same B/Victoria type lineage genetic group that dominates in the rest of Europe and that is included in the seasonal influenza vaccines.
Since March 14, the Örebro Region has been offering schoolchildren free influenza vaccination for a limited period. The European Centre for Disease Prevention and Control has launched an alert to facilitate the reporting of epidemiological information in all EU/EEA countries. It has also appealed to all other countries to provide as much data as possible on laboratory-confirmed cases of influenza B infection observed among children and adolescents and associated with severe outcomes.
To facilitate the reporting of epidemiological information from all countries on the European continent, ECDC will monitor EpiPulse, an online portal for European public health authorities and partner organizations to collect, analyze, share, and discuss infectious disease data for threat detection.