The Role of Co-infections and Secondary Infections in Patients with COVID-19
The study titled “The Role of Co-infections and Secondary Infections in Patients with COVID-19” provides a comprehensive review of the current literature on co-infections and superinfections in patients with SARS-CoV-2 infection.
Key aspects from the study include:
- Background and Impact of Co-infections and Superinfections: It is established that viral respiratory infections predispose patients to bacterial infections, leading to worse outcomes than either infection alone. This phenomenon is particularly notable in the case of COVID-19, where the roles of co-infections and superinfections are still being explored. The study examines various scenarios of co-infection, such as secondary SARS-CoV-2 infection following bacterial infection or colonisation, combined viral/bacterial pneumonia, and secondary bacterial superinfection following SARS-CoV-2 infection.
- Historical Context: The study provides a historical context by discussing how secondary bacterial infections played a major role in the mortality during the 1918–1919 influenza pandemic and subsequent pandemics. The importance of these secondary infections in planning and management during pandemics is emphasized, including the need for stockpiling antibiotics and vaccines.
- Coronavirus Infections and Co-infections: While initial studies on coronaviruses like SARS and MERS did not report high occurrences of co-infections or secondary infections, the emergence of COVID-19 brought renewed focus to this possibility. The study highlights that co-pathogens were encountered in 8% of patients with COVID-19, usually in more severely ill patients or those who died, indicating a higher likelihood of superinfections in later stages of illness.
- Mechanisms of Viral-Bacterial Interactions: The study delves into the mechanisms of viral-bacterial interactions. It reviews the interaction between the influenza virus and bacterial pathogens like S. pneumoniae and discusses mechanisms of interaction between SARS-CoV-2 and other pathogens, including the role of activated platelets in enhancing the risk of co-infections and superinfections.
- Molecular Pathogenesis: The study explains how SARS-CoV-2 can predispose patients to subsequent bacterial infections by causing damage to the respiratory epithelium and affecting innate and adaptive immunity. This may lead to enhanced bacterial adherence, colonization, growth, and invasion into healthy respiratory tract sites.
- Platelet-Driven Immunosuppression: The role of platelets in the pathogenesis of SARS-CoV-2 secondary infections is highlighted. Platelet-driven systemic immunosuppression can result from hyperactivation of platelets, leading to inflammation and contributing to the severity of COVID-19, ARDS, and cardiac dysfunction.
- NETosis and Secondary Infections: The formation of neutrophil extracellular traps (NETs) is driven by platelets and their inflammatory mediators. These NETs contribute to the pathogenesis of ARDS and cardiac damage associated with SARS-CoV-2, and can also lead to the development of secondary and super-bacterial infections.
- Treatment Considerations: The study notes that while co-infections and secondary infections in COVID-19 patients are associated with severe disease and poor outcomes, there is often no clear distinction in the literature between co-infections and secondary/superinfections. Systematic reviews and meta-analyses have found varying rates of co-infections and superinfections among COVID-19 patients, with the latter being associated with poorer outcomes.
In summary, the study provides an in-depth analysis of the complex interplay between COVID-19 and co-infections or superinfections, emphasizing the need for continued research and tailored treatment strategies in this area.