Mechanisms of Severe Mortality-Associated Bacterial Co-infections Following Influenza Virus Infection

Abstract

Influenza virus infection remains one of the largest disease burdens on humans. Influenza-associated bacterial co-infections contribute to severe disease and mortality during pandemic and seasonal influenza episodes. The mechanisms of severe morbidity following influenza-bacteria co-infections mainly include failure of an antibacterial immune response and pathogen synergy. Moreover, failure to resume function and tolerance might be one of the main reasons for excessive mortality. In this review, recent advances in the study of mechanisms of severe disease, caused by bacterial co-infections following influenza virus pathogenesis, are summarized. Therefore, understanding the synergy between viruses and bacteria will facilitate the design of novel therapeutic approaches to prevent mortality associated with bacterial co-infections.

Effectiveness of inactivated influenza vaccine against laboratory-confirmed influenza pneumonia among adults aged ≥65 years in Japan

“…Although a higher IVE estimate was observed for primary influenza pneumonia, IIV was also effective at preventing influenzaassociated bacterial pneumonia (49.1%; 95% CI, 17.1-68.7%). This finding is important because influenza-bacterial co-infection increases the risk of severe outcomes [32]. Our finding also suggests that IIV may be effective at preventing influenza pneumonia death; however, the association did not reach a statistically significant level because of the limited sample size.…”

Influence of influenza A virus in COVID-19 patients: A retrospective cohort study

“…In uenza infection is known to increase the host's susceptibility to bacteria, and bacterial co-infections following in uenza infection result in morbidity and mortality 5 , but there is limited data with co-existing respiratory viral infections. Detection of speci c IgM antibodies against viruses and other atypical pathogens has been widely applied for the diagnosis of respiratory infections 6 .…”

Influenza Virus in Community-Acquired Pneumonia: Current Understanding and Knowledge Gaps

“…34 Common bacteria involve in coinfection with influenza include Streptococcus, Staphylococcus, meningococci, Legionella, Haemophilus, Klebsiella, Campylobacter, Pseudomonas, Enterobacter, Acinetobacter, Burkholderia, and Mycobacterium. 35 Bacterial coinfection contributes to disease severity and ICU admission. 33 Although coinfection sometimes can result from immune-compromised status, coinfection per se is significantly associated with mortality.…”