Prolonged stress or chronic stress promotes susceptibility to diseases and infections such as sepsis, endocarditis, respiratory viral infections, meningitis, and other central nervous system infections.
This type of stress significantly affects the immune system by raising the levels of catecholamine (adrenaline and dopamine), glucocorticoids (e.g., cortisol), and suppressor T cells, which suppress the immune system, leading to an increased risk of viral infection .
Evidence of the Role of Chronic Stress in Promoting Viral Infections
A study investigated the effect of chronic stress on 144919 participants with stress-related disorders. They found that severe stress reactions were associated with an increased risk of life-threatening infections, regardless of socioeconomic factors, familial background, physical conditions at baseline (including baseline susceptibility to infection), and the occurrence of other severe somatic diseases during follow-up .
Although the study attempted to investigate the correlation between stress, infection, and glucocorticoid levels, this investigation led to mixed results. However, the authors of the study provided alternative explanations which relied on behavioral factors such as smoking, alcohol or drug use, and sleep disturbance.
They also suggested the potential role of childhood exposure to trauma that promotes inflammatory reactions and leads to neuropsychological and cognitive development consequently to epigenetic modifications.
Finally, the authors of the study suggest the use of selective serotonin reuptake inhibitors to attenuate the relative risk of life-threatening infections.
This study is one of the largest studies that investigated the role of chronic stress in promoting the risk of viral infections. It confirmed previous reports on this subject using a large number of participants which makes it significant. The study also pointed out the complexity of the causes of viral infections in response to chronic stress.
 Song, H., Fall, K., Fang, F., Erlendsdóttir, H., Lu, D., Mataix-Cols, D., de la Cruz, L.F., D’Onofrio, B.M., Lichtenstein, P., Gottfreðsson, M. and Almqvist, C., 2019. Stress related disorders and subsequent risk of life threatening infections: population based sibling controlled cohort study. bmj, 367.