Abstract:
BACKGROUND: It has been recognised for a considerable time-period, that viral respiratory infections predispose
patients to bacterial infections, and that these co-infections have a worse outcome than either infection on its own.
However, it is still unclear what exact roles co-infections and/or superinfections play in patients with COVID-19
infection.
MAIN BODY: This was an extensive review of the current literature regarding co-infections and superinfections in
patients with SARS-CoV-2 infection. The definitions used were those of the Centers for Disease Control and
Prevention (US), which defines coinfection as one occurring concurrently with the initial infection, while
superinfections are those infections that follow on a previous infection, especially when caused by microorganisms
that are resistant, or have become resistant, to the antibiotics used earlier. Some researchers have envisioned three
potential scenarios of bacterial/SARS-CoV-2 co-infection; namely, secondary SARS-CoV-2 infection following bacterial
infection or colonisation, combined viral/bacterial pneumonia, or secondary bacterial superinfection following SARSCoV-2. There are a myriad of published articles ranging from letters to the editor to systematic reviews and metaanalyses describing varying ranges of co-infection and/or superinfection in patients with COVID-19. The
concomitant infections described included other respiratory viruses, bacteria, including mycobacteria, fungi, as well
as other, more unusual, pathogens. However, as will be seen in this review, there is often not a clear distinction
made in the literature as to what the authors are referring to, whether true concomitant/co-infections or
superinfections. In addition, possible mechanisms of the interactions between viral infections, including SARS-CoV-2,
and other infections, particularly bacterial infections are discussed further. Lastly, the impact of these co-infections
and superinfections in the severity of COVID-19 infections and their outcome is also described.
CONCLUSION: The current review describes varying rates of co-infections and/or superinfections in patients with
COVID-19 infections, although often a clear distinction between the two is not clear in the literature. When they
occur, these infections appear to be associated with both severity of COVID-19 as well as poorer outcomes.
