This study aims to evaluate the effectiveness of an oral microbiome immunity formula in modulating gut microbiota, enhancing immunity and reducing long-term complications and co-morbidities in patients who have recovered from COVID-19.

SARS-CoV-2, the cause of COVID-19, emerged as a new zoonotic pathogen of humans at the end of 2019 and rapidly developed into a global pandemic. It may develop severe or critical disease with respiratory failure requiring oxygen support and intensive care.

Natural infection by virus triggers an effective system immunity so that the host can resist or highly reduce the chance of re-infection.

In many cases, this protection can maintain a long period of time. However, the long-term immunities (over a year) and complications from the patients are not yet very clear. We found that COVID-19 survivors who have cleared the virus continued to have persistent altered gut microbiota and up to 80 percent had residue COVID-19 related symptoms including fatigue, difficulty in breathing, impaired memory and hair loss up to 6 months after discharge (LONG COVID-19).

Earlier studies from our CU Medicine have shown a link between altered gut microbiome and COVID-19 severity, and more patients who received a novel microbiome immunity formula (SIM01) achieved complete symptom resolution and developed neutralising antibody than those who did not (unpublished data). Research from the Faculty also reported that almost 40% of people in Hong Kong had significant gut dysbiosis especially in elderly and patients with diabetes, obesity or chronic diseases.

This study is a single-centre, triple-blind, randomized, placebo-controlled clinical trial that aims to evaluate the effectiveness of an oral microbiome immunity formula (SIM01) invented by the Chinese University of Hong Kong (CUHK) in modulating gut microbiota, enhancing immunity and reducing long-term complications and co-morbidities (e.g. sepsis, cardiopulmonary complications, metabolic syndrome, neuropsychiatric disorders) in patients who have recovered from COVID-19.

Inclusion Criteria:

1. Individuals aged 18 and above;
2. Subjects who are mentally capable to participate in the study and provide informed consent;
3. Subjects who can communicate in Chinese or English;
4. Subjects who are ambulatory and do not have difficulties travelling to the clinics for follow-up;
5. Subjects who do not have plans to leave Hong Kong in the subsequent two years after recruitment; and
6. Subjects who agree to give informed consent voluntarily.

Exclusion Criteria:

1. Subjects who are unable to receive oral fluids;
2. Subjects who have received surgery involving the intestine within past 30 days;
3. Subjects who are pregnant or breastfeeding; and
4. Subjects who are immunocompromised, e.g. on cancer treatment, bone marrow/organ transplant, immune deficiency, poorly controlled HIV/AIDS.