Fungal pathogens are an increasing global public health concern. Over the course of the Covid-19 pandemic, the number of fungal infections increased markedly amongst hospitalised patients, according to the World Health Organization (WHO). A report published by the WHO in October 2022 outlined the first-ever list of ‘priority fungal pathogens’ that present the greatest threat to public health.

A number of fungal infection outbreaks occurred during the pandemic. According to a study published by Hoenigl and colleagues in Nature in August 2022, shortly after the emergence of Covid-19, a spike in invasive Candida infections was observed in patients with Covid-19 in the intensive care units (ICUs) of Wuhan. Additionally, during the second wave of the pandemic, India reported more than 47,500 cases of Covid-19 associated mucormycosis between May and August 2021. The people most at risk for fungal infections include those with underlying health conditions (for example, chronic lung disease, tuberculosis (TB), HIV, cancer, and diabetes), critically ill patients in an ICU, patients taking immunosuppressants, and those undergoing invasive medical procedures. 

Fungal infections are prevalent in all countries, rich and poor. However, there is a wide variation across the world, and they are more common in low- and middle-income countries. According to GlobalData’s forecast, in the 16 major markets (Australia, Brazil, Canada, China, France, Germany, India, Italy, Japan, Mexico, Russia, South Africa, South Korea, Spain, the UK, and the US) there is expected to have been over three million cases of invasive fungal infections in 2022.

Invasive fungal infections are an important complication in a significant number of critically ill, hospitalised patients with Covid-19. Three groups of fungal pathogens cause co-infections in Covid-19 patients, Aspergillus, Candida, and Mucorales species, with the former two classified as critical-priority according to the WHO pathogen list, and the latter as high priority. An infection with SARS-CoV-2 changes the immunological responses of patients, which can result in an inflammatory environment that allows fungal infections to thrive. This impairment in immune status associated with a Covid-19 infection explains why an increase in fungal infections has been seen over the pandemic.

According to GlobalData, globally there have been more than 630 million cases of Covid-19 to date. GlobalData Epidemiologists expect that as the world moves into the endemic stages of the COVID-19 pandemic, there may be an increase in invasive fungal infection concurrent with waves of Covid-19 infections. As vaccination has played an important role to minimise the number of people with severe illness associated with Covid-19, there is a smaller pool of susceptible individuals, so any increases in fungal infections will be of a smaller magnitude than that observed previously in the outbreak.

Despite the significant emerging public health threat posed by fungal pathogens, these infections receive relatively little attention and resources. This issue is compounded by the impact of climate change, which is altering the epidemiology and geographical reach of fungal pathogens. Anti-fungal resistance also poses a significant issue by affecting the ability to swiftly treat pathogens and mitigate outbreaks, particularly in hospital settings. Finally, in many settings, access to quality diagnostics and treatment is limited. Bearing these factors in mind, it is likely that globally there will be a continuation of this trend of increasing incidence over the coming years.