Comparative study on clinical characteristics between primary infection and re-infection of SARS-CoV-2

MENG Wanting; ZHAO Heng; WU Shunjun; SONG Liqiang

doi:10.13276/j.issn.2097-1656.2025.06.012

Abstract：Objective On December 7,2022,after the adjustment of the national severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)prevention and control policy,there was a large-scale epidemic.The main strain was Omicron BA.5.2 variant.Half a year later,the XBB variant epidemic led to repeated infection in some patients.This study aims to explore the correlation between two infections and their severity,so as to provide a reference for the formulation of clinical prevention and treatment plans.Methods All adult patients with confirmed SARS-CoV-2 infection who visited the fever clinic of Xijing Hospital,Air Force Medical University from May 8 to 14,2023 were selected as the research subjects.A WeChat management group was established and a cohort study was conducted using an electronic questionnaire.Information such as demographic characteristics,SARS-CoV-2 vaccination status,previous history,SARS-CoV-2 infection history,and clinical symptoms were collected to compare and analyze the differences in clinical characteristics between patients with re-infection and those with primary infection of SARS-CoV-2.The severity of the disease between the first and second infections of patients with re-infection was also compared.Results A total of 129 adult patients with confirmed non-severe SARS-CoV-2 infection were included in the study,including 65 cases of primary infection and 64 cases of re-infection.There was no statistical difference between the two groups in terms of gender,age,history of SARS-CoV-2 vaccination,etc.The incidence and severity of symptoms such as fever,cough,sputum production,dizziness,headache,and muscle soreness in patients with re-infection were lower than those in patients with primary infection(all P＜0.05),and the median time of symptoms to disappear was also shorter than that in patients with primary infection(4 d vs 7 d,P＜0.001).Among patients with re-infection,the severity of symptoms such as fever and cough in the second infection was lower than that in the first infection(all P＜0.05),and the disappearance time of the main symptoms was also shorter.Conclusion In two different variant strains of COVID-19 epidemic which occurred about half a year apart,the symptoms of patients with re-infection were milder and the course of the disease was shorter than patients with primary infection.Compared with the first infection in patients with re-infection,the symptoms of the second infection were milder and the recovery was faster.