Infection with the SARS-CoV-2 virus causes cardiopulmonary and vascular complications, ranging in severity. Understanding the pathogenic mechanisms of the novel SARS-CoV2 infection and progression can provide potential novel targets for its prevention and/or treatment. Virus microbiota reciprocal interactions have been studied in a variety of viral infections. For example, the integrity of Coronavirus particles can be disrupted by surfactin, a bacterial surface molecule that targets other viruses, including that of influenza A. In this light, intestinal microbiota likely influences COVID-19 virulence, while from its side SARS-CoV-2 may affect the intestinal microbiome promoting dysbiosis and other deleterious consequences. Hence, the microbiota pre-existing health status and its alterations in the course of SARS-CoV-2 infection, are likely to play an important, still underscored role in determining individual susceptibility and resilience to COVID-19. Indeed, the vast majority of COVID-19 worst clinical conditions and fatalities develop in subjects with specific risk factors such as aging and the presence of one or more comorbidities, which are intriguingly characterized also by unhealthy microbiome status. Moreover, these comorbidities require complex pharmacological regimens known as “polypharmacy” that may further affect microbiota integrity and worsen the resilience to viral infections. This complex situation may represent a further and underestimated risk with regard to COVID-19 clinical burden for the elderly and comorbid people. Here, we discuss the possible biological, physiopathological, and clinical implications of gut microbiota in COVID-19 and the strategies to improve/maintain its healthy status as a simple and adjunctive strategy to reduce COVID-19 virulence and socio-sanitary burden.

SARS-CoV-2 病毒感染会导致严重程度不等的心肺和血管并发症。了解新型 SARS-CoV2 感染和进展的致病机制可以为其预防和/或治疗提供潜在的新靶点。病毒微生物群的相互作用已在多种病毒感染中进行了研究。例如，冠状病毒颗粒的完整性可能会被表面活性蛋白破坏，表面活性蛋白是一种针对其他病毒（包括甲型流感病毒）的细菌表面分子。从这个角度来看，肠道微生物群可能会影响 COVID-19 的毒力，而从侧面来看 SARS-CoV- 2 可能影响肠道微生物群，促进生态失调和其他有害后果。因此，微生物群预先存在的健康状况及其在 SARS-CoV-2 感染过程中的变化可能在决定个体对 COVID-19 的易感性和恢复力方面发挥重要且仍被强调的作用。事实上，绝大多数 COVID-19 最严重的临床状况和死亡都是在具有特定风险因素（例如衰老和存在一种或多种合并症）的受试者中发生的，有趣的是，这些因素的特征还在于不健康的微生物组状态。此外，这些合并症需要复杂的药物治疗方案，称为“多重用药”，这可能会进一步影响微生物群的完整性并恶化对病毒感染的抵抗力。这种复杂的情况可能代表了老年人和合并症患者的 COVID-19 临床负担的进一步和被低估的风险。 在这里，我们讨论了肠道微生物群在 COVID-19 中可能的生物学、病理生理学和临床影响，以及改善/维持其健康状态的策略，作为降低 COVID-19 毒力和社会卫生负担的简单辅助策略。