Age and Sex Differences Among Mildly Symptomatic and Asymptomatic Patients with Omicron Infection in 2022 in Shanghai, China

Can Feng; Shihui Hong; Rong Fan; Xinjie Shi; Zhao Ma; Changgui Li; Chenghao Liu; Cong He; Min Fan; Ruiping Wang

doi:10.2147/JMDH.S375724

Age and Sex Differences Among Mildly Symptomatic and Asymptomatic Patients with Omicron Infection in 2022 in Shanghai, China

J Multidiscip Healthc. 2022 Aug 31:15:1909-1919. doi: 10.2147/JMDH.S375724. eCollection 2022.

Authors

Can Feng^#¹, Shihui Hong^#¹, Rong Fan^#¹, Xinjie Shi², Zhao Ma³, Changgui Li⁴, Chenghao Liu⁵, Cong He⁶, Min Fan¹, Ruiping Wang^{7

8}

Affiliations

¹ Department of Cardiology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, People's Republic of China.
² Department of Neurology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, People's Republic of China.
³ Department of Acupuncture and Moxibustion, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, People's Republic of China.
⁴ Department of Hematology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, People's Republic of China.
⁵ Department of Endocrinology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, People's Republic of China.
⁶ Department of Gastroenterology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, People's Republic of China.
⁷ Clinical Research Center, Shanghai Skin Diseases Hospital, Tongji University, Shanghai, People's Republic of China.
⁸ School of Public Health, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of China.

^# Contributed equally.

Abstract

Background: An epidemic of the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began in March 2022, and over 600,000 cases were confirmed until early May 2022 in Shanghai, China. Data on Omicron infections are available in other countries, but the clinical features of patients in the Chinese population, especially in Shanghai, are still lacking. We collected data from a subset of asymptomatic and mildly ill patients to learn about the age and sex disparity of Omicron infection based on changes in cycle threshold values.

Methods: The basic information of 325 patients who were consecutively admitted to the Shanghai Geriatrics Center was collected through medical records, and patients were tested for viral nucleic acid carriage using nasal swab samples during hospitalization. SAS 9.4 was used for data analysis, and a p value < 0.05% was considered statistically significant.

Results: Among the 325 included patients, 58.8% were males, with a mean age of 47.2 years and 13.6 days of hospitalization on average. The average number of nucleic acid tests among female patients was 4.7, which was higher than that among male patients (4.1). The median value of the slope for cycle threshold (Ct) changes in the nucleic acid detection (NAD) test was 1.4. Logistic regression indicated that the proportion of slope for Ct changes >1.5 was slightly higher among male patients than among female patients (odds ratio (OR) = 1.06, 95% confidence interval (CI): 0.68-1.66), and patients aged <45 years and 45-59 years had a higher proportion of slope for Ct changes >1.5 than patients aged ≥60 years. Ct values were more variable in the early stages of infection and stabilized in the later stages of infection.

Conclusion: Among patients with mild illness or asymptomatic infection, the Ct value is a good, timely, and cost-effective method to reflect the recovery progress of patients. The slope of Ct changes was steeper among younger patients and male patients, which indicates faster disease recovery.

Keywords: COVID-19; Omicron; RT‒PCR; SARS-CoV-2; cycle threshold; nucleic acid tests.

Grants and funding

This work was supported by a National Natural Science Foundation of China (NSFC) grant (82074266, 81904007), the Science and Technology Commission of Shanghai Municipality (STCSM) Research Fund (21JC1405300, 202040306), Yueyang Hospital Research Projects (2018YJ05), Shanghai Talent Development Fund (2021073), and China Fund for Medical Equipment (IIT2022-01).