Of 1,409 patients who attended Siriraj Hospital and underwent RT-PCR testing for SARS-CoV-2 to evaluate for COVID-19, 1,201 patients (85.2%) were symptomatic, and 208 patients (14.8%) were asymptomatic. Among those underwent RT-PCR testing, 1,029 patients (73.0%) had risk factors for COVID-19 infection, including history of contact with confirmed COVID-19 patients, history of foreign travel or contact with foreigners, and/or history of visiting crowded public areas (Figure 1). There were 107 adult patients with laboratory-confirmed COVID-19 (7.5%; 95% confidence interval [CI]: 6.2-9.0%), and 96 of those patients (89.7%) were diagnosed during 15 March 2020 to 14 April 2020.
Among the 107 patients with COVID-19, 101 patients (94.4%) presented with symptomatic infection, and 6 patients (5.6%) presented with asymptomatic infection. The proportion of COVID-19 among symptomatic patients was 8.4% (95% CI: 6.8-10.0%), whereas the proportion of COVID-19 among asymptomatic patients was 2.8% (95% CI: 0.6-5.2%). All patients with COVID-19 in our hospital had risk factors for acquiring SARS-CoV-2 infection. Eighty-six patients (80.4%) had a history of contact with confirmed COVID-19 patients from the clusters of COVID-19 outbreak in Thailand (boxing stadiums and pubs), and their families; 15 patients (14.0%) were imported infections; and, 6 patients (5.6%) had a history of visiting crowded public areas (markets, hotels, buses, and restaurants). The proportion of COVID-19 among patients with risk factors for COVID-19 infection was 10.4% (95% CI: 8.5-12.3%).
Among 102 patients with the result of their first PCR test available, the median cycle threshold (Ct) value of PCR was 25.2 (range: 11.3-40.0), and the median time from onset of illness to specimen collection was 3 days (range: 0-16). The Ct value of first PCR testing and timing from onset of illness to specimen collection are shown in Figure 2. Sixty-two patients (60.8%) from whom a specimen was collected within less than 5 days of symptom onset had a significantly lower median Ct value than the 40% of patients who had a specimen collected at 5 or more days after symptom onset (median Ct value of 21.9 [range: 11.3-37.2] vs. 27.0 [range: 15-40]; p<0.001). No significant difference in baseline Ct value (p=0.192) was found when compared among different clinical features on admission (Figure 3).
Comparison of COVID-19 patients with and without pneumonia
The clinical characteristics, laboratory findings, treatments, and outcomes of all COVID-19 patients, and compared between those with and without pneumonia are shown in Table 1 and Table 2. Of the 27 patients with COVID-19 pneumonia (25.2%), 19 were diagnosed with pneumonia at the time of admission, and 8 patients developed pneumonia during hospitalization. Median time from symptom onset to the development of pneumonia was 7 days (range: 1-18). Among the 19 patients who were diagnosed with pneumonia at the time of admission, bilateral opacities were found in 13 patients (68.4%), and the other 6 patients (31.6%) had unilateral involvement. All 8 patients who developed pneumonia thereafter had bilateral involvement on their chest X-ray. Patients with COVID-19 pneumonia were older, had a higher BMI, more likely to have comorbidity, more likely to have symptom, such as fever, cough, dyspnea and desaturation, lymphocytopenia, higher C-reactive protein (CRP), lower albumin, and higher globulin than those without pneumonia. Multivariate analysis revealed lymphocytopenia <1,000/mm3 (odds ratio [OR]: 21.4; 95% CI: 2.8-162.9; p=0.003) and high CRP level (OR: 45.7; 95% CI: 9.4-222.2; p<0.001) to be independent predictors of pneumonia.
Treatment and outcome
Among the 104 patients (97.2%) treated with antiviral medications, 78 (75.0%) received 2-drug antiviral therapy. Of those, 32 patients (41.0%) received lopinavir/ritonavir plus chloroquine, and 46 patients (59.0%) received darunavir/ritonavir plus hydroxychloroquine. Twenty-six patients (25.0%) received 3-drug antiviral therapy due to presence of pneumonia. The 3-drug regimen consisted of the 2-drug regimen plus favipiravir. Three patients (2 with URI and 1 with asymptomatic infection) received only symptomatic treatment. During treatment, 32 patients (29.9%) developed diarrhea with a median duration of 2 days after treatment (range: 1-3), and 24 patients (22.4%) developed nausea. However, all of those patients were clinically improved after symptomatic treatment.
Respiratory virus panels and bacterial cultures from respiratory samples were sent in 20 and 13 patients with community-acquired pneumonia, respectively; however, no respiratory coinfection was identified. No patients with COVID-19 received concurrent oseltamivir therapy. Antibiotic treatment was given in only 13 patients with COVID-19 (12.1%), and 3 patients received >1 course of antibiotic treatment. Ten patients received empiric antibiotic therapy for community-acquired infections (azithromycin in 4 patients, ceftriaxone plus azithromycin in 4 patients, and levofloxacin in 2 patients). Six patients received antibiotic treatment for nosocomial infections. Among those 6 patients, 5 received antibiotics for treatment of nosocomial pneumonia (meropenem in 3 patients, and piperacillin/tazobactam in 2 patients), and one patient received cefdinir and metronidazole for treatment of perianal abscess. One out of six patients who received antibiotic developed antibiotic-associated diarrhea, and was treated with oral vancomycin.
At the time of hospital discharge, 88 patients (82.2%) were classified as mild disease (80 non-pneumonia, and 8 mild pneumonia). Nine patients (8.4%) were classified as severe disease due to oxygen desaturation (SpO2 ≤93%) (1 patient had severe disease, and 8 patients had mild disease at the time of admission). The other 10 (9.3%) were classified as critical disease due to the development of ARDS (5 patients had severe disease, and 5 patients had mild disease at the time of admission).
Disease progression during hospitalization was observed in 18 patients (16.8%; 8 patients with severe disease, and 10 patients with critical disease). Median time from symptom onset to disease progression was 11 days (range: 4-16). Compared to those without disease progression, patients with disease progression were older (52.5 vs. 33 years, p<0.001), had a higher median BMI (26.3 vs. 22.9 kg/m2, p<0.01), presence of underlying disease (66.7 vs. 21.3%, p<0.001), pneumonia since first admission (55.6 vs. 10.1%, p<0.001), lower baseline lymphocyte count (1,071 vs. 1,690/mm3, p<0.001), higher baseline CRP (61.2 vs. 3.8 mg/L, p<0.001), lower albumin (3.8 vs. 4.3 g/dL, p<0.001), and higher globulin (3.8 vs. 3.1 g/dL, p<0.001).
Several interventions were administrated as adjunctive therapy in 12 COVID-19 patients who had severe or critical disease, including corticosteroid in 5 patients, corticosteroid with tocilizumab in 2 patients, corticosteroid with hemoperfusion in 2 patients, tocilizumab in 2 patients, and hemoperfusion in 1 patient. Multivariate analysis revealed presence of underlying disease (OR: 6.7, 95% CI: 1.7-26.2; p=0.006) and high CRP level (OR: 55.2, 95% CI: 6.7-465.2; p<0.001) to be independent factors associated with disease progression. All patients with COVID-19 in our hospital were clinically improved and discharged alive. The median length of stay was 11 days (range: 2-38), and was significantly longer among those with pneumonia (14 vs. 10.5 days, p<0.001).