Preplanned Studies: Dynamic Disease Manifestations Among Non-Severe COVID-19 Patients Without Unstable Medical Conditions: A Follow-Up Study — Shanghai Municipality, China, March 22–May 03, 2022
We enrolled 33,816 SARS-CoV-2 positive participants (Supplementary Figure S1, available in 网页链接) 21,619 (63.9%) patients were male, the median age of patients was 44.5 years, 1,273 (3.7%) patients aged <18, 26,948 (76.7%) patients aged 18–59, and 5,595 (16.5%) patients aged ≥60. 9,260 (27.4%) patients had risk factors, and 6,333 (18.7%) of whom had comorbidities. Among patients with comorbidities, hypertension was the most common comorbidity (4,902/6,333, 77.4%), followed by diabetes mellitus (1,641/6,333, 25.9%) and lung disease (329/6,333, 5.2%) (Figure1A). Among all participants, most (32,688/33,816, 96.7%) had fewer than two comorbidities. Most of the participants had received full or booster vaccination: 73.1% in risk-group subjects and 80.6% in non-risk group subjects (Figure 1B); 76.2% and 78.6% of participants were ultimately diagnosed with asymptomatic infection in the risk group and the non-risk group, respectively (Figure 1C). Cough and sputum production were the most common symptoms (19.0%), followed by fatigue (5.2%) and fever (4.0%). VST was longer in the risk group [6 days, interquartile range (IQR): 4–9 days] than in the non-risk group (6 days, IQR: 3–8 days) (P<0.001) (Figure 1D). VST was shorter in vaccinated subjects (6 days, IQR: 3–8 days) than in non-vaccinated subjects (6 days, IQR: 3–8.25 days) (P<0.001). The median duration of symptom persistence was 7 days. Dynamic changes in viral load are shown in Supplementary Figure S2 (available in 网页链接).
Compared to patients under 40 years old, patients 40–59 years old [aHR: 0.90; 95% confidence interval (CI), 0.88–0.92], 60–79 years old (aHR: 0.85; 95% CI, 0.82–0.88) and ≥80 years old (aHR: 0.73; 95% CI, 0.65–0.84) had longer VSTs in the Cox proportional hazards model (Table 1). In model 1, presence of comorbidities (aHR: 0.96; 95% CI, 0.93–0.98) and being initially symptomatic (aHR: 0.95; 95% CI, 0.93–0.98) were also associated with increased VST; being fully vaccinated (aHR: 1.06; 95% CI, 1.03–1.10) and booster vaccinated (aHR: 1.07; 95% CI, 1.03–1.10) were associated with decreased VST. In model 2, VST was longer in the risk group than in the non-risk group (aHR: 0.89; 95% CI, 0.87–0.92) (Figure 1E).
In the entire study cohort, 22 patients developed severe/critical infection; all were in the risk group. Severity rates among all subjects and risk-group subjects were 0.065% and 0.238%, respectively. Hypertension (31.8%) was the most common comorbidity, followed by diabetes (13.6%) and lung disease (13.6%). Patients in the risk group who developed severe/critical infection were older (75.8±10.7 vs. 60.0±11.3, P<0.001) and were more likely to be unvaccinated (54.5% vs. 24.2%; P=0.002). (Table 2)