Introduction:
The novel coronavirus disease (COVID-19) or
SARS-CoV-21 gained attention after a citywide lockdown
was implemented in Hubei, China.2 To date, COVID-19
had infected more than 3,000,000 people in the world. This pandemic has
currently left more than 230,000 dead and almost two-thirds of the
world’s countries locked down.3,4
Malaysia recorded its first confirmed COVID case on
25th January 2020.5 At the time of
writing, Malaysia tallied 6176 confirmed cases and 103
deaths.6 Kuching, the most populated city in Sarawak,
was among the areas with most confirmed COVID-19 cases and death in
Malaysia.7 Majority of the cases in Malaysia were
contributed by a few clusters, including one religious assembly event in
East Malaysia.8
SARS-CoV-2 virus displayed high transmissibility (R0 of
2.68)9 and longer incubation period (6 days)9 compared to the Middle East Mediterranean virus. The
virus can transmit form human-to-human via respiratory droplets,
aerosol, and fecal-oral route. These natures of the virus may explain
the rapid spread of the global pandemic and high case-fatality
rate.10
Healthcare workers are not spared from this disease.11China12 recorded 3.47% and Netherlands 4-9.5% of
infected healthcare workers (HCW).13 Contact tracing
revealed most of the infected HCW acquired the infection from the
community.14 The total number of HCW with COVID-19
infection will continue to rise, given that many countries have yet to
reach the peak of the outbreak.
Patients with COVID-19 infection displayed a wide spectrum of disease
severity,14 including asymptomatic or mild
symptoms.13,15 Statistical modeling correctly
predicted near to 18% of asymptomatic infection in the Diamond Princess
cruise ship cluster.16 Most HCW (80%) with confirmed
COVID infection expressed mild symptoms without a strong epidemiological
link.13,17 HCW expressing mild or no symptom could be
the vulnerable group to be prioritized for the COVID-19 serology
screening.18
Because symptoms of COVID-19 infection differed across the board, it is
difficult to separate the infected and the healthy by clinical and
epidemiological factors alone. WHO recommended the virus nucleic acid
Real-Time Polymerase Chain Reaction test (RT-PCR) test as a laboratory
diagnostic tool.19 However, the use of RT-PCR testing
is currently rationalized due to testing capacity with priority given to
specific individuals, i.e. higher risk.18 Thus, human
antibody rapid test may be an alternative because of this
limitation.20
Human antibody acute response (IgM) to COVID-19 infection begins at the
median timing of 5 days from illness onset.21 IgG
antibody, which represents possible past exposure is usually detectable
in plasma or seroconvert from IgM after day 10 of
illness.22,23 PCR tests are more sensitive to yield
positive results in the first week of illness. This sensitivity reduces
towards the end of the second week.24 Hence this
antibody temporal relationship can be used to guide the COVID-19
diagnosis after one week of illness25 and identify a
person with previous undiagnosed infection.18 It has
proven good sensitivity and specificity to supplement the test of
molecular laboratory diagnosis.26
Being the only non-COVID-19 tertiary hospital and the only public
cardiology centre in Sarawak, the Sarawak Heart Centre (SHC) plays a
supporting role as the healthcare burden escalated in the other regional
medical facility designated as a COVID-19 hospital healthcare, the
Sarawak General Hospital (SGH). To date, no cases of confirmed COVID had
been admitted or treated in our centre. All cases fulfilling the
criteria for person under investigation (PUI) were referred to the
designated COVID-19 centre. There is a total of 757 staff, including 71
working in non-clinical field. None of the healthcare workers in our
centre have been diagnosed with COVID-19 infection thus far.
Our hospital’s COVID-19 taskforce team decided to assess the possibility
of unknown disease transmission due to either community or nosocomial
exposure among our healthcare workers. Knowing the antibody response of
our staff can also give us some idea of the effectiveness of our
in-hospital infection control measures. Because RT-PCR test is
prioritized for high-risk patients only, we chose the COVID-19 antibody
serology test as the mode of investigation. This survey is self-funded
with approval from hospital administration to protect staff’s wellbeing
during this pandemic. Our decision echoes World Health Organization’s
(WHO) suggestion to prioritize COVID-19 testing among healthcare worker
to prevent potential nosocomial spread.18