Increased viral load and weaker immune response tied to severe COVID-19 infection among elderly, reveals study
As the COVID-19 pandemic continues to affect people of all ages, a new study has delved into the reasons why older individuals face a higher risk of severe illness from the virus. The study found that the most severe impact was seen in the oldest adults, who exhibited higher levels of pro-inflammatory genes and proteins during severe disease, indicating that the body’s response to the virus becomes increasingly dysregulated with age. The study results were published in the journal Science Translational Medicine.
The research, conducted on a cohort of 1,031 vaccine-naïve patients hospitalized for COVID-19, aimed to unravel the mysteries behind the relationship between age and disease severity. Led by a team of researchers, the study focused on analyzing the immune response of individuals across a wide age range, from 18 to 96 years old. Using advanced techniques such as mass cytometry, serum protein profiling, antibody assays, and transcriptomics, the scientists explored how aging influences the body's ability to combat the virus. Their findings revealed several key insights into the impact of age on COVID-19 outcomes. Firstly, older patients exhibited higher levels of the virus upon hospital admission and experienced delayed clearance of the virus from their bodies. This suggests that aging may impair the body's ability to effectively eliminate the virus, leading to prolonged illness and increased risk of complications.
Furthermore, the study uncovered age-related changes in the immune system, with older individuals showing alterations in both innate and adaptive immune responses. Specifically, there was an upregulation of innate immune signaling pathways and a downregulation of adaptive immune signaling pathways in older patients. This imbalance in immune function could contribute to the severity of COVID-19 in older adults. One notable finding was the decrease in naïve T and B cells—the immune cells responsible for recognizing and attacking new pathogens—in older individuals. Additionally, older patients had higher levels of monocytes, which are involved in inflammatory responses, further highlighting the dysregulation of the immune system with age. Importantly, the study also revealed that older adults experienced sustained activation of pro-inflammatory genes and elevated levels of serum chemokines, which are proteins involved in guiding immune cells to infection sites. This persistent inflammatory response may contribute to the development of severe COVID-19 symptoms in older patients.
The most concerning aspect of the research was the observation that the oldest adults exhibited the highest levels of pro-inflammatory genes and proteins during severe disease, indicating a heightened risk of complications with age. Overall, the study provides valuable insights into the biological mechanisms underlying the increased susceptibility of older individuals to severe COVID-19. By understanding these mechanisms, researchers hope to develop targeted treatments that could help improve outcomes for older patients battling the virus.
Further reading: Host-microbe multiomic profiling reveals age-dependent immune dysregulation associated with COVID-19 immunopathology. Doi: 10.1126/scitranslmed.adj51
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