Results:
Subject Demographic (Table 1)
310 staff were recruited into this study. The mean age was 36±7.6 years old (range: 23-70 years old), and 220(71%) were female. In this population, 17(5.5%) were cardiology doctors, 6(1.9%) were from clinical research centre, 20(6.5%) worked in the non-invasive catheterization laboratory, 20(6.8%) stationed in the invasive cardiac laboratories, 26(8.4%) from the radiology department, while 132(42.6%) stationed in the wards including coronary care unit, day care ward, and cardiac rehabilitation wards. Job positions were categorized into the following groups: doctor 37(11.9%), nurse 165(53%), allied healthcare personnel 96(31%), and non-clinical staff 12(3.9%). 162(52.3%) of these staff resided in Kota Samarahan, while 107(34.5%) in Kuching, and the remainders from peripheral towns, 42(13.2%).
Clinical Symptoms (Table 1)
A total of 46(14.8%) staff reported having experienced at least one respiratory or atypical respiratory symptom on at least one occasion, between February 2020 and early April 2020. The most common symptom was cough, 32(10.3%) followed by sore throat 31(10%), fever 11(3.5%), and runny nose 22(7.1%). 3(1.0%) staff had experience shortness of breath and 1(0.3%) staff reported abdominal discomfort and diarrhoea.
Epidemiological Factors (Table 1)
4(1.3%) staff reported having returned from a foreign country in the preceding two months. There were 24(7.7%) staff with a history of possible close contact while providing medical care to patients who were later confirmed to be infected by COVID-19. 24(7.7%) of study participants also reported to having visited areas with known COVID clusters.
Antibody Serology Results (Table 1) (Figure 4)
14 staff (4.5%) tested positive, 2(0.6%) for IgM and 12(3.9%) for IgG. All 14 staff were subsequently tested negative for COVID-19 RT-PCR nasopharyngeal swab tests. The two staff with faint IgM positive results were proven to be falsely positive, confirmed by negative RT-PCR test, as well as negative IgG antibody on day 14 of symptoms onset.
Among staff who developed IgG, eight were female, four worked in the emergency unit, five under general cardiology unit and one from non-clinical unit. More nurses developed IgG response compared to other categories of staff. Majority of the staff (9) with positive IgG result resided in Kota Samarahan, which was the immediate area where SHC was located.
Epidemiological factors that were significantly associated with IgG response among the staff were cluster contact (20% vs. 2.8%, p=0.009). The presence of clinical symptoms, at least one respiratory symptom was also found to be significantly associated with the IgG response (12.2% vs. 2.7%, p=0.021). History of close contact to known COVID-19 patient or travel abroad were not found to be associated with IgG response. Hence, the presence of either a clinical symptom or having epidemiological factors were found to be significantly related to the antibody serology result.
Sub analysis excluding emergency unit staff found a weak association between IgG response with the place of work within the cardiology department (wards 0.76% vs. other areas 6%, p=0.045). Emergency unit staff showed a higher likelihood of acquiring IgG antibody comparing to the other units, albeit falling short of statistical significance (6.3% vs. 3.4%, p=0.298).