The following is a summary of “Global analysis of respiratory viral circulation and timing of epidemics in the pre–COVID-19 and COVID-19 pandemic eras, based on data from the Global Influenza Surveillance and Response System (GISRS),” published in the April 2024 issue of Infectious Diseases by Riccio et al.

The COVID-19 pandemic changed respiratory virus interventions, such as using masks to avoid possible viral interactions. 

Researchers conducted a retrospective study to determine whether the respiratory virus’s circulation patterns are back to pre-pandemic levels by comparing peak timing and duration during the first three SARS-CoV-2 seasons to pre-pandemic times. 

They used data from the Global Influenza Surveillance and Response System (GISRS) from 194 countries (2014 to 2023) to examine epidemic peak timing and duration. The focus was on pre-pandemic and pandemic periods across both the hemispheres and intertropical belts, with strict criteria for data inclusion ensuring robustness. 

The results showed that from 2022 to 2023, the flu and RSV peaked earlier in the northern hemisphere by 1.9 months (P<0.001). Influenza epidemics lasted 2.2 weeks longer (P<0.001), with RSV showing a similar trend. The southern hemisphere’s influenza peak shift was not significant (P=0.437). In intertropical regions, hMPV and adenovirus epidemics were shorter by 7.2 and 6.5 weeks, respectively (P<0.001). 

Investigators concluded that the pandemic changed the typical patterns of influenza and RSV, hitting peaks in temperate regions in 2022. The need for robust surveillance data to guide future public health plans on viral patterns continues to evolve. 

Source: ijidonline.com/article/S1201-9712(24)00122-X/fulltext#%20