COVID-19: Delayed Immune Responses Drive Death Rates Among Men and the Elderly

Varying immune responses to SARS-CoV-2, the virus that causes COVID-19 due to age and sex, may depend on viral load and the time-course of infection, revealed a study published in the open-access journal PLOS Biology. The study was conducted by Nicole Lieberman and Alexander Greninger at the University of Washington and colleagues.

Study Participants

‘Immune responses to COVID-19 may depend on the viral load and infection time course.’

For the study, viral RNA from swabs collected from 430 COVID-19 positive cases and 54 negative controls were extracted and sequenced. Researchers studied the hosts' antiviral and immune responses across infection status, viral load, age, and sex.

Study Results

- After three days following the onset of infection, the immune cell responses were not activated.
- Immune cell composition and function fluctuated with viral loads in males and the elderly.

According to the authors, "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."

While the study has important implications for developing immunomodulatory treatments for SARS-CoV-2, additional studies are needed as swabs were taken from the nasopharynx, which is not a sensitive anatomic location for accurately examining markers of systemic inflammation.

Source: Medindia