The characteristics of peripheral blood and immune status in patients with influenza and COVID-19 co-infection

Aim – to study the changes in peripheral blood parameters and immune status in patients with mixed infection and to assess the risks of developing pulmonary fibrosis.

Material and methods. We examined 25 patients aged 23 to 72 years with co-infection in the acute phase of the disease, who were hospitalized at the infectious diseases hospital based in the OrSMU research center. The markers of cellular immunity, percentage of phagocytic cells and phagocytic index, the level of immunoglobulins of classes A, M, G, and cytokines were registered in all examined patients.

Results. The suppression of cellular immunity parameters, primarily the T-immune system, was revealed in elderly patients with co-infection, along with patients with an isolated course of COVID-19. In young and middle-aged patients, we found multidirectional changes in cellular immunity parameters during influenza and COVID-19 co-infection. An increase in IL-6 and TGF-β in the early stages of the disease was registered in patients with an isolated course of COVID-19 infection.

Conclusion. The changes in the immunity during co-infection are not pronounced enough for the development of lungs fibrous in the acute period of the disease. The possibility of detecting influenza viruses in patients with COVID-19 may change the strategy of treatment and suppression of cytokine storm reactions in critically ill patients.