Study shows COVID-19 activity peaks during winter in the United States and Europe


In a latest examine posted to the Research Square* preprint server, researchers from Columbia College Mailman College of Public Well being, Pfizer Inc, and the College of Iowa assessed the seasonal tendencies noticed in coronavirus illness 2019 (COVID-19) circumstances, hospitalizations, and deaths.

Within the winter, a number of respiratory viruses trigger waves of illness that observe particular seasonal patterns. Along with elevated indoor exercise and seasonal climate variations identified to have an effect on viral stability outdoors the host, these tendencies are in all probability the results of a confluence of hosts, pathogens, and environmental components. Due to this fact, intensive analysis is required to find out whether or not extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at present follows or will finally observe seasonal patterns just like these different respiratory viruses.

Concerning the examine

Within the current examine, researchers assessed the seasonal patterns noticed in COVID-19 circumstances, hospitalizations, and deaths within the US and Europe utilizing time collection fashions.

The ecological investigation was performed by adhering to the Strengthening the Reporting of Observational Research in Epidemiology (STROBE) requirements. The Our World in Information (OWID) GitHub repository was used to acquire day by day charges of COVID-19 infections, hospitalizations, and mortalities noticed per million inhabitants by the nation for the US, the UK, and the entire European Union’s member nations. Information utilized for the examine was recorded between 1 March 2020 and 31 July 2022 as obtainable by nation.

The workforce decomposed day by day country-specific time collection charges similar to COVID-19 circumstances, hospitalizations, and fatalities individually utilizing a Prophet time collection mannequin. Moreover, the time collection mannequin was adjusted for the nation stringency index.


The examine outcomes confirmed that the mannequin demonstrated clear annual seasonality constant throughout all of the SARS-CoV-2 infections, hospitalizations, and loss of life charges recorded between November and April 2021. The yearly seasonal part’s extra influence on circumstances was probably the most vital between January and March 2021, with a peak extra seasonal fee worth of 905 circumstances noticed per 1,000,000 individuals.

Examine: Seasonal trends in COVID-19 cases, hospitalizations, and deaths in the United States and Europe. Picture Credit score: fanasiev Andrii / Shutterstock

With as much as 100 extra seasonal hospitalizations per 1,000,000noted between November and April, the annual seasonal part for hospitalizations demonstrated a transparent distinction between seasons. With an extra two mortalities per 1,000,000 folks on account of the annual seasonal impact, which is predominantly concentrated from November via February, COVID-19-associated mortality confirmed an analogous sample within the annual seasonal part. The entire nations assessed confirmed related patterns. The annual seasonality of pre-pandemic influenza that was constantly noticed between December and April over twelve US influenza seasons was additionally demonstrated by the exact mannequin specs described for charges of COVID-19.

Heatmap of the influenza percent positivity median annual seasonal component by month, Oct 2009 through Dec 2021. Data Source: World Health Organization

Heatmap of the influenza % positivity median annual seasonal part by month, Oct 2009 via Dec 2021. Information Supply: World Well being Group


The examine findings confirmed that regardless of steady COVID-19 transmission all year long, the variety of COVID-19 circumstances, hospitalizations, and deaths was the best through the winter viral respiratory season within the US and Europe. Due to this fact, the researchers counsel utilizing annual preventative measures in opposition to SARS-CoV-2, such because the administration of seasonal booster vaccines or different non-pharmaceutical interventions to most people in a timeframe just like these employed for influenza prevention to curb COVID-19 transmission.

*Vital discover

Analysis Sq. publishes preliminary scientific reviews that aren’t peer-reviewed and, subsequently, shouldn’t be considered conclusive, information scientific apply/health-related habits, or handled as established data.

Leave A Reply