Delayed Immune Response to SARS-CoV-2 Explain Why More Men Die from COVID-19

A study by researchers from the University of Washington (Seattle, Wash., USA) suggests that varying immune responses to SARS-CoV-2 due to age and sex could explain why COVID-19 infections tend to be more severe among older adults and males.

The SARS-CoV-2 virus causes more severe COVID-19 infections and higher mortality among elderly and male patients as compared to women, indicating that weaker immune responses may be contributing to the underlying poor clinical outcomes for these two demographics. However, scientists have not yet been able to understand the mechanisms behind the increased death rate among these two patient populations caused by SARS-CoV-2.

The University of Washington researchers attempted to better understand the mechanisms behind the varied response of COVID-19 infected patients among different demographics by extracting and sequencing viral RNA from swabs collected from 430 COVID-19 positive cases and 54 negative controls. The researchers then went on to analyze their antiviral and immune responses across infection status, viral load, age and sex. They found that the immune cell responses were activated only three days after the start of infection, and also observed fluctuations in immune cell composition and function with viral loads, pointing to a dysfunctional antiviral response in males and the elderly. The findings of the study have significant implications for the development of immunomodulatory treatments for SARS-CoV-2

In their study published in the open access journal PLOS Biology, the authors wrote, "Collectively, our data demonstrate that host responses to SARS-CoV-2 are dependent on viral load and infection time with observed differences due to age and sex that may contribute to disease severity."

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