Resurgence of Legionella: A Post-COVID-19 Concern

Abstract

The COVID-19 pandemic has dealt a heavy blow to every continent globally. Most fatalities during the pandemic were due to subsequent bacterial infections; however, Legionella and SARS-CoV-2 co-infections were relatively rare yet significant. COVID-19 pandemic countermeasures (e.g., social distancing, mask wearing, etc.) appeared to be effective at reducing the occurrence of infections that were transmitted from person to person (e.g., pneumococcal disease). Conversely, these nonpharmaceutical interventions might marginally impact environmentally transmitted pathogens, such as Legionella pneumophila. In addition, it is suggested that COVID-19-associated stagnation may increase the incidence of legionellosis. Herein, we addressed the significant concern of whether Legionella is making a post-COVID-19 comeback. Few post-COVID Legionella studies collectively indicate a spike in Legionella activity associated with extended water stagnations due to the COVID-19 lockdown. In addition, surveillance data from a few countries (e.g., European Union countries) depicted a significant upward trend in the incidence of legionellosis especially after the pandemic restrictions had been eased. In the future, well-planned environmental surveys and global disease surveillance are required to monitor this respiratory pathogen in the post-COVID-19 landscape. Facility managers may develop robust water management programs and continue to adhere to them to detect and remediate Legionella within building water systems.