Eurosurveillance - Volume 28, Issue 11, 16 March 2023

An individualised blood donor selection policy was implemented in the United Kingdom from summer 2021. We have investigated the impact of this policy by comparing the extent of undeclared use of HIV pre-exposure or post-exposure prophylaxis (PrEP/PEP) before and after this change. The rate of PrEP usage in syphilis-positive male blood donors has not changed since individualised donor assessment was implemented but provides continuing evidence of undisclosed PrEP use which may be associated with current or past higher-risk sexual behaviours.

With COVID-19 public health control measures downgraded in China in January 2023, reported COVID-19 case numbers may underestimate the true numbers after the SARS-CoV-2 Omicron wave. Using a multiplier model based on our influenza surveillance system, we estimated that the overall incidence of SARS-CoV-2 infections was 392/100,000 population in Beijing during the 5 weeks following policy adjustment. No notable change occurred after the Spring Festival in early February. The multiplier model provides an opportunity for assessing the actual COVID-19 situation.

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.

The development, and in some cases increasing prevalence, of resistance to antimicrobials used in clinical and veterinary settings has long been recognised. In recent years, the concept of ‘One Health’ has added recognition of the role that the environment plays in health protection along with the need for protection of the health of the environment itself. Organisations including the World Health Organization, United Nations Environment Programme, and national governments have identified a need for surveillance of antimicrobial resistance in the environment to sit alongside the surveillance carried out in clinical, veterinary and food sectors. However, having recognised the need for environmental surveillance there are multiple challenges in deciding what this should entail. For example, what pathogens or genes to monitor, who or what we wish to protect and what measures we wish to enable to decrease infection risks. That might include sampling near a source of resistant organisms entering the environment or conversely sampling where the exposure actually occurs. Choices need to be made at both policy and technical levels based on the detailed purposes of surveillance. This paper discusses these issues from the perspective of a national environmental regulator.