Tap water as the source of a Legionnaires' disease outbreak spread to several residential buildings and one hospital, Finland, 2020 to 2021.

In Finland, all microbiology laboratories notify Legionella findings and physicians notify Legionnaires' disease (LD) cases to the National Infectious Disease Register. All cases are interviewed, and water samples obtained from potential places of exposure. Legionella isolates from humans and water are compared by whole genome sequencing (WGS). In March 2021, Legionella pneumophila serogroup 1 (Lp 1) pneumonia cases increased in one Finnish city (120,000 inhabitants) where single LD cases are detected annually. We identified 12 LD cases, nine living in different residential buildings and three nosocomial, linked by identical human and/or water isolates. Three of these cases were from January 2020, October 2020 and February 2021 and identified retrospectively. Eleven were diagnosed by urinary antigen test, 10 by PCR and five by culture; age ranged between 52 and 85 years, and 10 had underlying diseases. Nine of 12 homes of LD cases and 15 of 26 water samples from the hospital were positive for Lp 1, with concentrations up to 640,000 cfu/L. Water samples from regional storage tanks were negative. Positivity in homes and the hospital suggested inadequate maintenance measures. Enhanced surveillance combined with WGS was crucial in detecting this unusual LD outbreak related to domestic and hospital water systems.

Support among healthcare workers for the new mandatory seasonal influenza vaccination policy and its effects on vaccination coverage.

INTRODUCTION: Finland was the first European country to introduce a nation-wide mandatory seasonal influenza vaccination policy for healthcare workers (HCWs) by mandating that administrators of health care institutions only employ vaccinated HCWs. In this study, we examine the effects of the new policy and the view of HCWs on the new policy. METHODS: A cross-sectional observational study was conducted in Kuopio University Hospital among HCWs working in close patient contact. The statistics on vaccination coverage were obtained from the hospital's own databases, where employees were asked to self-report their suitability for work. An anonymous survey was sent to HCWs in 2015-2016 (n = 987) and 2018-2019 (n = 821). RESULTS: Vaccination coverage increased from 59.5 to 99.6%, according to the hospital's own records. Among the survey respondents, the seasonal influenza vaccination coverage of HCWs increased from 68.2 to 95.4%. 83.8% of doctors and 49.4% of nurses supported the new policy. 12.7% of doctors and 41.5% of nurses found the new mandate coercive or that it restricted their self-determination. CONCLUSIONS: Our study confirms the positive effects of mandating the administrators of health care institutions to only employ vaccinated HCWs. The majority (57.9%) of all HCWs supported the new policy, with doctors being more compliant than nurses. Key messages Finland became the first European country to mandate influenza vaccination for HCWs by mandating that administrators of health care institutions only employ vaccinated HCWs. After the new act, the vaccination coverage of HCWs increased close to 100%. Most of the HCWs supported the new act and did not find it coercive.