Clinical researchers from The Chinese University of Hong Kong's (CUHK) Faculty of Medicine (CU Medicine) have identified for the first time distinct gut microbiome profiles associated with post-acute Covid-19 syndrome, more commonly known as "long Covid". These distinct gut microbial signatures can be used to predict the risk of developing long Covid and diagnose long Covid in patients with persistent symptoms after the acute infection. This is the world's first study to demonstrate gut microbiota as a key determinant of long COVID. Study results have been published in the international journal Gut. 

In a pilot study, the team has also shown that a novel gut microbiome immunity formula (SIM01) developed by CUHK can prevent the development of long Covid. CU Medicine is now conducting a randomised clinical trial using the SIM01 formula to modulate patients' gut microbiota to prevent and treat long Covid.

For the first time, clinical researchers from CU Medicine have identified distinct gut microbiome profiles associated with long Covid. These distinct gut microbial signatures can be used to predict the risk of developing long Covid and diagnose long Covid in patients with persistent symptoms after the acute infection.

For the first time, clinical researchers from CU Medicine have identified distinct gut microbiome profiles associated with long Covid. These distinct gut microbial signatures can be used to predict the risk of developing long Covid and diagnose long Covid in patients with persistent symptoms after the acute infection. (From left) Professor Siew NG, Associate Director of the Centre for Gut Microbiota Research; Professor Francis CHAN, Dean of Medicine and Director of the Centre for Gut Microbiota

Diagnosis of long Covid is often delayed because symptoms are non-specific and there is no specific test to explain long Covid symptoms. The development of non-invasive, microbiome-based profiling will be a useful tool for the timely detection of long Covid.

The gut microbiome test for long Covid is an innovative technology of the Microbiota I-Center (MagIC) funded by InnoHK, an initiative of the HKSAR Government's Innovation and Technology Commission. CUHK Medical Centre will be the first in Hong Kong to provide this innovative test.

Over 90% of patients who received SIM01 did not develop long Covid

Treating long COVID is challenging given that, until recently, there has been no definitive clinical test for diagnosis, and there is no standard treatment yet. A recent pilot study conducted by the research team showed that in patients who received CUHK's microbiome immunity formula SIM01 for four weeks, over 90% of them did not develop long COVID up to a year of follow-up.

Professor Francis KL CHAN, Dean of Medicine and Director of the Centre for Gut Microbiota Research at CU Medicine, remarked, "Since the outbreak of COVID-19 in 2020, more than 500 million people worldwide have been infected. Our results showed that almost 80% of our local patients suffer from long COVID. Our discovery not only for the first time offers a scientific explanation for long COVID, but also provides an effective tool for prediction, diagnosis and treatment of this global health problem."

Professor Siew Chien NG, Associate Director of the Centre for Gut Microbiota Research at CU Medicine, added, "Our study showed that microbiome-based profiling is potentially useful for risk assessment, timely diagnosis and targeted treatment of long COVID. These new findings also indicate that in addition to hastening recovery from acute COVID-19 infection, a microbiome immunity formula (SIM01) is potentially effective in preventing long COVID."

CU Medicine has started a large-scale randomised clinical trial to study the efficacy of SIM01 in preventing and treating long COVID. Professor Martin Chi Sang WONG, Professor from The Jockey Club School of Public Health and Primary Care at CU Medicine, said, "We are currently recruiting recovered COVID-19 patients who have persistent symptoms into a clinical trial that aims to reduce long COVID by modulating their gut microbiota." This study is supported by the Health and Medical Research Fund of the HKSAR Government's Food and Health Bureau.