Semiannual seasonality of COVID-19 with alternating peaks in winter and summer.

Authors

Hao Zhang, Jian Wang

Published in

Frontiers in public health. Volume 14. Pages 1877365. Epub Jun 26, 2026.

Abstract

To examine the presence of seasonality and characterize the temporal epidemic patterns of COVID-19 incidence during the main pandemic period.
The Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (ICEEMDAN) method was used to systematically analyze COVID-19 incidence time series during the main pandemic period (March 1, 2020-February 28, 2023) from global, hemispheric, and key national perspectives.
Eight distinct epidemic waves occurred worldwide during the study period. The temporal pattern exhibited alternating peaks in winter and summer, corresponding to a semiannual cycle identified through time-series decomposition. This "winter-summer dual-peak" pattern was consistently observed across multiple spatial scales, although with regional variability in amplitude and timing.
COVID-19 exhibited a clear semiannual seasonal pattern, differing from the typical unimodal winter dominance observed in many respiratory infectious diseases. This pattern may be associated with seasonal variations in environmental conditions. These findings may contribute to understanding the temporal dynamics of COVID-19 under normalized conditions and may provide reference for future studies on emerging respiratory infectious diseases.

PMID:
42433403
Bibliographic data and abstract were imported from PubMed on 11 Jul 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.