HK’s first territory-wide long COVID study to inform follow-up care

Researchers at the Chinese University of Hong Kong (CUHK) have rolled out the city’s first territory-wide study of long COVID to inform multidisciplinary follow-up care for thousands of COVID-19 survivors. Participants are also invited to a second-phase 3-year prospective study of the impact of gut dysbiosis on long COVID symptoms and the potential role of gut microbiome modulation in treatment of long COVID.

The study, supported by the Hospital Authority (HA), will evaluate symptoms of long COVID and their impact on patients’ health, family and work. Individuals who have recovered from COVID-19, including the elderly and children, are invited to complete a 2-minute, bilingual, online, multiple-choice questionnaire accessible on cuhk.hk/longcovid or via QR codes displayed at HA’s Western and Chinese medicine outpatient clinics.

Long COVID prevalent, symptoms diverse

“Our recent study showed that 76 percent of COVID-19 patients in Hong Kong had at least one symptom 6 months after recovery [from acute infection],” said Professor Francis Chan, Dean of Medicine and Director of the Centre for Gut Microbiota Research, CUHK. [Gut 2022;71:544-552]

“With 1.27 million people having had SARS-CoV-2 infection in Hong Kong, more than 900,000 individuals are estimated to suffer from long COVID, which affects multiple systems and organs, requiring multidisciplinary care,” Chan noted. “Our territory-wide survey, with a target recruitment of 10,000 participants, will inform healthcare policymaking relevant to the care of these patients.”

“Our pilot study in 554 COVID-19 survivors showed that 69.5 percent had moderate or severe long COVID,” said Professor Siew Ng of CUHK’s Department of Medicine and Therapeutics and Director of CUHK’s Microbiota-I Centre.

The most common moderate-to-severe symptom was fatigue (33.7 percent), followed by neuropsychiatric symptoms (eg, poor memory, anxiety, insomnia, loss of taste and smell) (27.1–30.5 percent) and respiratory symptoms (eg, cough, sputum, shortness of breath) (23.8–31.9 percent). Musculoskeletal symptoms (eg, joint pain, muscle pain) (29.9 percent), gastrointestinal symptoms (eg, nausea, diarrhoea) (23.3–24.6 percent) and dermatological symptoms (eg, hair loss) (24.7 percent) were also common.

“A larger-scale study is needed to provide more accurate prevalence figures,” said Ng.

Gut microbiome modulation: Role in long COVID treatment?

The researchers also aim to recruit 1,000 participants of the long COVID survey into the second-phase study, in which participants will provide faecal samples every 6 months for gut microbiome evaluation. “The objective is to investigate the potential role of gut microbiome modulation in treatment of long COVID,” said Ng.

In a recent study, the researchers identified distinct gut microbiome profiles associated with long COVID, which can be used for risk prediction and diagnosis of long COVID following acute infection. Compared with controls, the gut microbiome of patients with long COVID is characterized by lower diversity, lower relative abundance of bacteria beneficial to host immunity, and higher relative abundance of unfavourable bacteria. [Gut 2022;71:544-552]

“Applied on >1,200 samples, our machine learning model accurately predicted the risk of long COVID [based on the gut microbial biomarkers] and identified the long COVID gut microbiome to be a cause of post-acute symptoms,” reported Ng. “The sensitivity was 92 percent, and specificity was 93 percent.”

“Among COVID-19 patients treated with a novel gut microbiota–derived symbiotic formula known as SIM01, 94 percent were free of long COVID symptoms throughout 1 year of follow-up,” she added.

One-stop long COVID clinic

At CUHK Medical Centre (CUMC), a one-stop multidisciplinary long COVID clinic was launched several months ago to provide personalized care based on gut microbiome assessment results. “We will need to expand the service to several HA clinics and integrate it with Chinese medicine. This will be the future direction of long COVID management,” said Ng.