At the request of the Public Health Agency, the following information and appeal for typing of influenza cases at ICU in Sweden is sent. They write: " We have seen an increased number of patients at ICU with influenza, mainly influenza A in recent weeks. Few of the patients have their samples subtyped to influenza A(H3N2) or A(H1N1)pdm09. As we have both types circulating in Sweden, it is important to know the distribution among the critically ill."
Request for influenza positive samples from ICU patients
Thank you for your valuable reporting on ICU-treated patients with influenza and covid-19 respectively. The data is monitored on an ongoing basis and is an important part of the Public Health Agency's surveillance. Summary statistics and situation assessment are reported via the weekly reports.
Samples from ICU-treated patients
When influenza is detected in an ICU patient, we request that the sample is sent to the Public Health Agency for sub/line typing and further characterisation. In order for this to happen, the laboratories need information about ICU care through the referral, for example write "ICU patient, subtyping needed" on the referral. If the regional laboratory is able to subtype, it is useful if this analysis is done on site, before the sample is sent to the Public Health Agency.
Background
We see that a low proportion of patients in ICU with influenza A have their samples subtyped to influenza A(H3N2) and A(H1N1)pdm09 respectively. Of 129 patients with influenza A reported so far, only 19 have reported influenza A subtypes (15%). Since we have both types circulating in Sweden, it is important to know the distribution among the critically ill. By extension, also to follow any changes in severity or risk groups per subtype.
More info
Disease information on influenza
Current influenza report (updated Fridays)
Questions about the Public Health Agency's virus characterisation should be addressed to
inflanalyser@folkhalsomyndigheten.se