Seasonal rhythms within immune systems may explain infection rates – study

Study finds fluctuations in white blood cells according to time of day and season, suggesting stronger or weaker immune function

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Clocks and calendars within our immune systems could render us more susceptible to infection and injury at certain times of day or months of the year, a new study suggests. A better understanding of these rhythms could have implications for the prevention and treatment of diseases like Covid-19. It could also help explain why certain illnesses, like flu, tend to strike in winter, while the symptoms of other diseases, like multiple sclerosis, often worsen in summer.

Although recent studies have hinted that there may be seasonal or daily circadian" rhythms in our immune function, this hadn't been confirmed in large numbers of people until now.