Drivers of Infectious Disease Seasonality: Potential Implications for COVID-19

Abstract

Not 1 year has passed since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19). Since its emergence, great uncertainty has surrounded the potential for COVID-19 to establish as a seasonally recurrent disease. Many infectious diseases, including endemic human coronaviruses, vary across the year. They show a wide range of seasonal waveforms, timing (phase), and amplitudes, which differ depending on the geographical region. Drivers of such patterns are predominantly studied from an epidemiological perspective with a focus on weather and behavior, but complementary insights emerge from physiological studies of seasonality in animals, including humans. Thus, we take a multidisciplinary approach to integrate knowledge from usually distinct fields. First, we review epidemiological evidence of environmental and behavioral drivers of infectious disease seasonality. Subsequently, we take a chronobiological perspective and discuss within-host changes that may affect susceptibility, morbidity, and mortality from infectious diseases. Based on photoperiodic, circannual, and comparative human data, we not only identify promising future avenues but also highlight the need for further studies in animal models. Our preliminary assessment is that host immune seasonality warrants evaluation alongside weather and human behavior as factors that may contribute to COVID-19 seasonality, and that the relative importance of these drivers requires further investigation. A major challenge to predicting seasonality of infectious diseases are rapid, human-induced changes in the hitherto predictable seasonality of our planet, whose influence we review in a final outlook section. We conclude that a proactive multidisciplinary approach is warranted to predict, mitigate, and prevent seasonal infectious diseases in our complex, changing human-earth system.

Seropositivity in blood donors and pregnant women during the first year of SARS‐CoV‐2 transmission in Stockholm, Sweden

“…Therefore, the levels of past infection in this cohort may be slightly higher than we report. Anti-SARS-CoV antibodies have been reported to persist for 3 years following more severe infection [42,43], while detectable responses to seasonal coronaviruses generally wane within 1-2 years and immunity is affected by rhythms in their circulation [44][45][46]. Importantly, as the activated B-cell pool and antibody response contracts following viral clearance (and declines in function with age [47,48]), the identification of low but persistent antibody responses (that may be highly effective) remains a challenge using conventional serological methods.…”

Differential effects of COVID-19 lockdowns on well-being: interaction between age, gender and chronotype

“…The COVID-19 pandemic provides a unique opportunity to test the effects of social and mobility changes on wellbeing. Importantly, these effects may also indirectly affect the immune system: sleep, biological rhythms and wellbeing are all interconnected, and affect our immune system function and ability to fight viral infections [28][29][30][31][32][33][34]. Therefore, understanding these relations may also help us develop protective recommendations for reducing the risk of infection and improve vaccination outcomes [33], which may be different for different subpopulations.…”

The Circadian Clock, the Brain, and COVID-19: The Cases of Olfaction and the Timing of Sleep

“…A number of excellent reviews in this journal ( Sengupta et al, 2021 ; Kronfeld-Schor et al, 2021 ; Haspel et al, 2021 ) and elsewhere ( Baig, 2020 ; Paterson et al, 2020 ; Ray and Reddy, 2020 ; Asadi-Pooya and Simani, 2020 ; Varatharaj et al, 2020 ) provide important explorations of what we now know about the neurobiology of COVID-19, including daily and seasonal variations in neuroimmune function, both in the intensive care unit and in the environment, which can affect SARS-CoV-2 infectivity and mortality. In this perspective paper, our goal is to shed light on how clock regulated neuropathology of COVID-19 could be evaluated, quantified, and used diagnostically.…”