I believe that a weakened immune system, partly due to impaired interferon function, leaves the body more susceptible to additional infections.
Just because we believe we've recovered from an infection doesn't necessarily mean our immune system—specifically our IgG antibodies—is fully functioning.
In a recent video presentation (translated from German to English), Prof. Dr. Dunja Bruder shared this insight:
“…My suspicion is that viral infections can leave long-lasting effects on the body.”
“Shockingly, traces of these infections can still be detected in the cerebrospinal fluid (CSF) up to eight months after the initial illness.”
Her example: Viral Infections:
A Serious Concern for Physical Exercise
How can damaged lungs—particularly malfunctioning alveoli—adequately supply the oxygen needed for exercise, if oxygen cannot efficiently reach the muscles?
Excerpt:
Why certain pneumococcal serotypes can be particularly dangerous after a bout of influenza. While over 90 serotypes are known, only a few cause invasive, life-threatening infections. Prof. Dunja Bruder's team was able to demonstrate for the first time in a preclinical mouse model how a recovered influenza infection influences the response of alveolar type II epithelial cells to various pneumococcal serotypes. "In contrast to previous studies, which mostly examined secondary infections during the acute phase of influenza, our work shows that susceptibility to pneumococci persists during the recovery phase – but primarily to invasive serotypes," summarizes Bruder. The new findings on epigenetic and immunological changes in AECII provide valuable mechanistic clues as to how previous viral infections can sustainably impair the antibacterial defense capacity of the lungs – an aspect that could be important in the long term for the development of improved therapeutic and diagnostic approaches for bacterial superinfections.
More at:
https://www.helmholtz-hzi.de/en/research/research-groups/details/immune-regulation/