LONGECITY

"COVID-19 does eliminate a significant number of T-cells, enough to make large numbers of sick people overwhelm emergency wards with RSV (respiratory syncytial virus), pneumonia, strep infections and other ailments."

https://www.therecor...2ef8cea80e.html

The study claims HIV is the only other infection capable of this. They're clear that COVID is nowhere as severe as HIV. But the loss of T-cells largely explains the rise in other infections we have been seeing.

Additional research supporting this concern:

T-cell recovery and evidence of persistent immune activation 12 months after severe COVID-19
2022 Aug
https://pubmed.ncbi....h.gov/35567391/

"T-cell numbers and function recover in most patients after COVID-19. However, we find evidence of persistent T-cell activation up to 12 months after infection and describe a subgroup of severe COVID-19 patients with persistently low CD8+ T-cell counts exhibiting a dysregulated immune response during acute infection."


A role for T-cell exhaustion in Long COVID-19 and severe outcomes for several categories of COVID-19 patients
2021 Jul 19
https://pubmed.ncbi....h.gov/34288064/


Elevated exhaustion levels and reduced functional diversity of T cells in peripheral blood may predict severe progression in COVID-19 patients
17 March 2020
https://www.nature.c...1423-020-0401-3

"Recent studies have shown that in addition to dyspnea, hypoxemia, and acute respiratory distress, lymphopenia, and cytokine release syndrome are also important clinical features in patients with severe SARS-CoV-2 infection.3 This suggests that homeostasis of the immune system plays an important role in the development of COVID-19 pneumonia."


Immunosuppression as a Hallmark of Critical COVID-19: Prospective Study
23 May 2021
https://www.mdpi.com...-4409/10/6/1293


SARS-CoV-2-induced immunodysregulation and the need for higher clinical suspicion for co-infection and secondary infection in COVID-19 patients
February 2021
https://www.scienced...684118220302140

"Currently, the pathogenic mechanisms underlying the SARS-CoV-2 infection associated with immune dysfunction that permits secondary infection are not well understood.... Co-infection prevalence is estimated to be as high as 50% among COVID-19 fatalities.9"

Influenza can also weaken the immune system and lead to pneumonia.

Influenza can also weaken the immune system and lead to pneumonia.

That's a good point. I also found some evidence to support it.

Neutrophil-mediated T-Cell Suppression in Influenza: Novel Finding Raising Additional Questions
https://www.atsjourn...cmb.2017-0425ED

Has there been any investigation into the severity or incidence rate? I think it's important to do a detailed comparison, both statistically of morbidity and theoretically of suggested mechanisms of action.

It's worth considering all differences between influenza and the novel coronavirus. Perhaps one evolves faster. Perhaps a lack of initial immunity caused a high case fatality rate, but it's equally possible that COVID produces a more severe or inflammatory immune response.

A Comparison of COVID-19 and Influenza-Associated Myocarditis: A Nationwide Study in the United States
2023 Mar 12
https://www.ncbi.nlm...es/PMC10008141/

"There are many similarities between COVID-19 and influenza infections such as viral transmission, risk factors for infection, and the range of symptoms.4 However, there are also clear differences. The intense cytokine storm that occurs during COVID-19 can result in myocardial inflammation without the presence of viral particle in myocardial biopsy while influenza myocarditis appears to be related mainly to direct viral invasion of myocytes."

Infections respiratory diseases may accelerate aging via the production of senescent cells. However, I would be surprised if covid didn't cause more damage (like senescent cells) than influenza.

OTOH, influenza occurs every year and mitigation is half-hearted at best and wrong at worst. It kills up to 500k each year, which approaches the number of deaths per decade (5 million) as covid (using the 7 million low-end estimate) caused in 3 years. The protection offered by flu vaccines isn't that great; during some flu seasons, vaccines don't match the strains which are circulating due to manufacturing lag, and the elderly generally respond less well to vaccines than younger people. Besides getting a vaccine, the only other WHO/CDC recommendations are the usual fomite/droplet avoidance advice which won't work. Mask use is an afterthought, if it's mentioned at all, and respirators are never mentioned. So, I can see how over a lifetime of exposure, damage from the flu may equal or exceed damage from covid.