This study aims to examine the association between gut microbiota composition and themagnitude and duration of immune response in subjects who have received differentCOVID-19 vaccines in Hong Kong and to identify the differences compared to those COVID-19recovered subjects.
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 in March 2020. Over 106 million
COVID-19 cases including 2.3 million deaths have been reported to the WHO as of February
9th 2021. Overall 80% of cases are mild/moderate or asymptomatic while 20% may develop
severe or critical disease with respiratory failure requiring oxygen support and
intensive care. As of 16 February 2021, 10789 cases have been confirmed in HK with 193
deaths while 10231 patients have been discharged from acute public hospitals with a mean
length of stay of 15 days. Up to 16 Feb., 2021, there were 568 patients with COVID-19
have been managed at the Prince of Wales Hospital (PWH) with 12 deaths.
Studies showed that the quality of life of the patients who have recovered from COVID-19
was impaired. This situation is similar to some patients who suffered from SARS-CoV1
infection in 2003.
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. On the other hand,
vaccination, which aims to induce the similar immunity but in a controlled manner,
presents only selected antigen(s) to the host through different delivery strategies.
Lacking a normal virus replication cycle, vaccination can only partially mimic the
infection process that makes the immunogenicity or durability of the vaccines sometimes
not as effective as natural infection. This situation was also observed during the
development of SARS and MERS vaccines. A number of studies focused on examining the
humoral and cellular immunities from the COVID-19 patients during their acute stage or
only few months after recovery. However, the long-term immunities (over a year) from the
patients are not yet very clear.
The HKSAR government has procured 2 different types of COVID-19 vaccines for all the HK
citizens that is one of the few regions/countries adopt this strategy. BioNTech mRNA
vaccination programme will commence in early March 2021 and Sinovac inactivated whole
virus vaccine will also be available soon for vaccination after formal approval recently.
All these vaccines are so far only evaluated at their own designated population and
countries and there is still lack of prospective study to "side-by-side" comparing the
microbial biomarkers in the stool of different vaccines. Having different vaccines which
will soon be available in Hong Kong, it would be of great interest to investigate and
compare the microbial biomarkers in the stool of recovered COVID-19 patients versus those
who have received different COVID-19 vaccines by setting up a 2-year longitudinal study.
Inclusion Criteria for Vaccination (VAC) cohort:
1. aged ≥ 18 years old; and
2. have documented to have no previous COVID-19 infection; and
3. will receive any type of COVID-19 vaccines; and
4. agree to hand in study samples (stool and blood); and
5. agree to sign the informed consent
Inclusion Criteria for COVID-19 convalescent (CON) cohort:
1. aged ≥ 18 years old; and
2. recovered from varying severity of COVID-19; and
3. agree to hand in study samples (stool and blood); and
4. agree to sign the informed consent
Exclusion Criteria:
- None
Prince of Wales Hospital
Hong Kong, Hong Kong
Siew Ng, Principal Investigator
CUHK-M&T