METHODS: A total of 15,598 patients, 96% fully vaccinated and 52% boosted, from Xiangyang, China, who had symptomatic COVID-19 and chest CT scans during the first Omicron BF.7 wave in December 2022 to January 2023, were followed through the second Omicron XBB.1.5 wave between May and August 2023. A total of 17,968 second-wave patients with COVID-19 with chest CT scans but without previous symptomatic COVID-19 were enrolled as first-time infection controls.
RESULTS: A total of 19.6% (3,061 of 15,598) first-wave patients were diagnosed with pneumonia. Among second-wave reinfected patients, only 0.2% (four of 2202) developed pneumonia, which was lower than the 1.7% (311 of 17,968) pneumonia prevalence among the second-wave first-time patients, with an adjusted relative risk of 0.11 (95% confidence interval: 0.04-0.29). A total of 1.3% (40 of 3,039) first-wave pneumonia survivors showed residual abnormal patterns in follow-up CT scans within 8 months after pneumonia diagnosis.
CONCLUSIONS: In a highly vaccinated population, previous symptomatic Omicron infection within 8 months reduced pneumonia risk during reinfection. Uninfected individuals might need up-to-date vaccination to reduce pneumonia risk.
方法:15,598名患者,96%完全接种疫苗,52%加强疫苗接种,来自襄阳,中国在2022年12月至2023年1月的第一次omicronBF.7波中有症状的COVID-19和胸部CT扫描,随后在2023年5月至8月之间进行了第二次omicronXBB.1.5波。17,968例接受胸部CT扫描但没有症状性COVID-19病史的第二波COVID-19患者作为首次感染对照。
结果:19.6%(3,061/15,598)的第一波患者被诊断为肺炎。在第二波再次感染的患者中,只有0.2%(4/2,202)患有肺炎,低于第二波首次患者的1.7%(311/17,968)肺炎患病率,调整后相对风险(RR)为0.11(95%CI:0.04-0.29)。1.3%(40/3,039)的第一波肺炎幸存者在肺炎诊断后8个月内的随访CT扫描中显示出残留的异常模式。
结论:在高度接种疫苗的人群中,在8个月内之前有症状的omicron感染降低了再感染期间的肺炎风险.未感染的人可能需要最新的疫苗接种,以降低肺炎的风险。