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Fungal Infections Increase Mortality Among COVID Patients (51 notícias)

Publicado em 11 de setembro de 2022

In addition to aspergillosis, a disease caused by fungi of the genus Aspergillus, there are two other groups of co-infections with COVID-19. Fungi of the order Mucorales are responsible for mucormycosis, which occurs mainly in India and Pakistan, while yeasts of the genus Candida cause candidiasis and are present almost worldwide.

“Patients with this co-infection are twice as likely to die as patients infected with SARS-CoV-2 alone,” said Martin Hoenigl, first author of the study, Agência FAPESP. Hoenigl is a professor at the University of California, San Diego, La Jolla (USA) and the University of Graz, Austria.

Antifungal infections and COVID

According to the article, aspergillosis can remain confined to the upper respiratory tract for many days and can be stopped with antifungals. However, when it affects the blood vessels of the lungs, the mortality rate exceeds 80%, even with systemic antifungal therapy.

Candidiasis occurs almost exclusively in patients in intensive care units and is no more common in patients with COVID-19 than in those hospitalized for other reasons. However, Candida auris, which is a fungus, is a concern because it can colonize the skin. In addition, it appears to be the only fungus that is transmitted between humans. The species is resistant to all known antifungal drugs and, when found in a wide range of environments, can easily infect patients on ventilators or with catheters and other invasive life support equipment present in hospitals (more at: agencia.fapesp.br/36111 ) .

Mucormycosis (CAM) associated with COVID-19 is a serious problem, especially in India, where the number of cases has doubled during the pandemic. News of this mycosis gained international attention in 2021, when more than 47,500 cases were reported in India from May to August alone. The Indian government at the time classified it as an epidemic and mistakenly called it “black fungus” because of the color of the tissue necrotized by the disease. True black mushrooms belong to another group that is relatively distant from the Mucorales and does not cause disease in humans.

In patients with COVID-19, mucormycosis often occurs in the eyes and nose and can reach the brain. The mortality in these cases is 14% when the two diseases occur together. Because mucormycosis causes necrosis, surgery may be required and the patient may be disfigured as a result. Patients who survive may lose part of their face and suffer from problems for the rest of their lives. If the lungs are damaged or the fungus spreads throughout the body, the mortality rate reaches 80%.

“The prevalence of this mycosis in India was 0.27% in patients hospitalized with COVID-19, although it is common in people outside hospitals, such as those treated at home with very high doses of systemic steroids, which are readily available to most Indians , ” Hoenigl said.

The use of steroids and other drugs that reduce the activity of the immune system is one of the reasons for the worldwide increase in fungal infections. Although the strategy was successful during the pandemic and the benefits outweighed the risks, the researchers caution that it is important to avoid overusing immunosuppressants.

Alternatively, some high-risk centers for aspergillosis have successfully implemented antifungal prophylaxis during pandemics by prescribing drugs before exposure to these agents. However, because fungi are often resistant to most available drugs and there are insufficient clinical studies to evaluate the strategy, it is not currently recommended.

“Immunosuppressants are a great advance in medicine. They prevent many deaths from cancer and autoimmune diseases, and they also play a key role in organ transplantation. However, a side effect of their use has been a significant increase in the number of fungal infections,” said Goldman. “With the exception of some heat-resistant species such as A. fumigatus, fungi generally cannot withstand the body temperature of mammals and are easily fought by our innate immunity. But when our immune system is too weak to fight highly inflammatory diseases like COVID-19, they take the opportunity to attack us.”

New medicines

In addition, many fungi are adapting to higher temperatures as the global climate warms, and this also makes humans more vulnerable. As a result, new antifungal drugs are urgently needed, experts agree. Currently, there are only four classes of antifungal drugs compared to dozens of classes of antibacterial (antibiotics), e.g.

Another problem is the difficulty of diagnosing fungal infections. Diagnostic tests are too expensive for most people in low- and middle-income countries, and test results may take too long to become available to prescribe the right treatment.

For example, a 100% certain diagnosis of aspergillosis requires a bronchoscopy, a type of examination that is considered very risky during the COVID-19 pandemic and is therefore avoided as much as possible. The amount of fluid removed by the patient during the procedure is more than enough to transmit SARS-CoV-2 to the medical team. Cases of aspergillosis are probably underestimated as a result.

“The good news is that several new classes of antifungal drugs have been developed and are now in phase 2 and 3 clinical trials,” Hoenigl said.

However, researchers fear that these new drugs will not reach everyone who needs them. Advanced treatments can only remain in rich countries, as inequalities in access are likely to persist.

“With global warming, few available drugs and diseases that weaken the immune system causing epidemics and pandemics, outbreaks of fungal infections are very likely. We need more tools to fight them and more scientists to study different fungi and their mechanisms of action,” – Goldman said.

Source: Eurekalert