Establishing a sentinel surveillance system for the novel COVID-19 in a resource-limited country: methods, system attributes and early findings

Abstract

Objectives: To establish a hospital-based platform to explore the epidemiological and clinical characteristics of patients screened for COVID-19.

Design: Hospital-based surveillance.

Setting: This study was conducted in four selected hospitals in Bangladesh during 10 June-31 August 2020.

Participants: In total, 2345 patients of all age (68% male) attending the outpatient and inpatient departments of surveillance hospitals with any one or more of the following symptoms within last 7 days: fever, cough, sore throat and respiratory distress.

Outcome measures: The outcome measures were COVID-19 positivity and mortality rate among enrolled patients. Pearson's χ² test was used to compare the categorical variables (sign/symptoms, comorbidities, admission status and COVID-19 test results). Regression analysis was performed to determine the association between potential risk factors and death.

Results: COVID-19 was detected among 922 (39%) enrolled patients. It was more common in outpatients with a peak positivity in second week of July (112, 54%). The median age of the confirmed COVID-19 cases was 38 years (IQR: 30-50), 654 (71%) were male and 83 (9%) were healthcare workers. Cough (615, 67%) was the most common symptom, followed by fever (493, 53%). Patients with diabetes were more likely to get COVID-19 than patients without diabetes (48% vs 38%; OR: 1.5; 95% CI: 1.2 to 1.9). The death rate among COVID-19 positive was 2.3%, n=21. Death was associated with age ≥60 years (adjusted OR (AOR): 13.9; 95% CI: 5.5 to 34), shortness of breath (AOR: 9.7; 95% CI: 3.0 to 30), comorbidity (AOR: 4.8; 95% CI: 1.1 to 21.7), smoking history (AOR: 2.2, 95% CI: 0.7 to 7.1), attending the hospital in <2 days of symptom onset due to critical illness (AOR: 4.7; 95% CI: 1.2 to 17.8) and hospital admission (AOR: 3.4; 95% CI: 1.2 to 9.8).

Conclusions: COVID-19 positivity was observed in more than one-third of patients with suspected COVID-19 attending selected hospitals. While managing such patients, the risk factors identified for higher death rates should be considered.

Keywords: COVID-19; diagnostic microbiology; epidemiology; public health.

Figure 1

Location of the study hospitals and proportionate distribution of enrolled patients at different sites with their COVID-19 positivity, June to August 2020

Figure 2

SARS-CoV-2 infection among suspected COVID-19 patients at inpatient and outpatient departments of selected hospitals during June to August 2020, Bangladesh. A. Detection of SARS-CoV-2 at all four selected hospitals over time. B. Detection of SARS-CoV-2 at inpatient and outpatient departments of selected hospital sites. rRT-PCR, real-time reverse transcription-PCR.

Figure 3

Distribution of SARS-CoV-2 infected patients by their clinical features and comorbidity in selected hospitals of Bangladesh, June-August 2020. A. Presenting symptoms of all COVID-19 suspected patients by rRT-PCR results. B. Presenting symptoms of COVID-19 patients by department. C. COVID-19 positive patients by their comorbidity.