Clinical characteristics of COVID-19 patients infected by the Omicron variants in Macao, China: A cross-sectional study

Abstract

Background and aims: The evolving mutants of SARS-CoV-2 have made the COVID-19 pandemic sustained for over 3 years. In 2022, BA.4 and BA.5 were the Omicron variants dominating the spread globally. Although COVID-19 was no longer a Public Health Emergency of International Concern (PHEIC) as announced by WHO, the SARS-CoV-2 variants remain a challenge to global healthcare under the circumstances of withdrawal and loosening of personal protective behavior in the post-quarantine era. This study aims to acknowledge the clinical characteristics caused by Omicron BA.4/BA.5 in COVID-19 naive people and analyze possible factors affecting disease severities.

Methods: In this retrospective study, we report and analyze the clinical features of 1820 COVID-19 patients infected with the BA.4/BA.5 Omicron variants of SARS-CoV-2 during a local outbreak that occurred in Macao SAR, China, from June to July 2022.

Results: A total of 83.5% of patients were symptomatic eventually. The most common symptoms were fever, cough, and sore throat. Hypertension, dyslipidemia, and diabetes mellitus were the leading comorbidities. There were significantly more elderly patients (p < 0.001), more patients with comorbidity (p < 0.001) and more patients without vaccination or not completing the series (p < 0.001) in the "Severe to Critical" group. All deceased patients were elderly with at least three comorbidities and were partial to totally dependent in their daily lives.

Conclusion: Our data are consistent with a milder disease caused by BA.4/5 Omicron variants in the general population, while patients with old age and comorbidities have developed severe to critical diseases. Complete vaccination series and booster doses are effective strategies to reinforce protection against severe diseases and avoid mortality.

Keywords: infectious diseases; public health; respiratory medicine; vaccines.

Figure 1

Chest computed tomographic (CT) images of critical cases of COVID‐19 patients in Macao from June 18 to July 31, 2022. Day 3 of hospitalization (88‐year‐old female, third death case): Small ground glass opacities (GGO) in right middle lobe. (B) Day 8 of hospitalization (86‐year‐old female, fifth death case): Small patch of GGO in right lung. (C) Day 12 of hospitalization (93‐year‐old male, sixth death case): Small peripheral GGO with intralobular reticulations and minimal pleural effusions in bilateral basal lungs. (D) Day 2 of hospitalization (71‐year‐old female on mechanical ventilation): multiple infiltrates and ground glass opacities in both lungs.