Chapter 11 - COVID-19 and secondary fungal infections

Abstract

Since the beginning of the COVID-19 pandemic in 2020, more than 490 million cases and 6 million deaths have been confirmed to date (https://covid19.who.int/). In the course of the rising numbers, this viral infection may result in an enhanced susceptibility to secondary infections, including fungal infections, similar to what was already known from influenza virus. The vast majority of secondary systemic fungal infections have been observed among critically ill patients with COVID-19 often requiring invasive ventilation in intensive care units (ICUs). The high prevalence of COVID-19-associated pulmonary aspergillosis (CAPA) early during the pandemic (38%) raised awareness of potential secondary fungal infections complicating the disease course. Relative to infections caused by Aspergillus spp., mucormycosis, which is caused by fungi of the order Mucorales, is rare in most regions of the world, yet a deadly disease entity. India is a notable exception, where the enormous outbreak of COVID-19-associated cases of mucormycosis (CAM) in 2021 attained worldwide attention. Both CAPA and CAM are accompanied by devastatingly high mortality rates (~50% and ~80% [pulmonary/disseminated form], respectively) and exhibit profound challenges in diagnosis. Lastly, an increasing number of invasive Candida infections was noted in ICU patients with COVID-19, resulting in an introduction of the term COVID-19-associated candidiasis.