SARS-CoV-2 infection could cause persistent lung injury or indicate potential genetic susceptibilities. While infection-elicited hybrid immunity could protect against severe COVID-19, it remains unknown whether recent infection could reduce pneumonia risk during reinfection due to insufficient viral and chest CT screening. 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. 17,968 second-wave COVID-19 patients with chest CT scans but without prior symptomatic COVID-19 history were enrolled as first-time infection controls. 19.6% (3,061/15,598) first-wave patients were diagnosed with pneumonia. Among second-wave reinfected patients, only 0.2% (4/2,202) developed pneumonia, which was lower than the 1.7% (311/17,968) pneumonia prevalence among second-wave first-time patients, with adjusted relative risk (RR) of 0.11 (95% CI: 0.04-0.29). 1.3% (40/3,039) first wave pneumonia survivors showed residual abnormal patterns in follow-up CT scans within 8 months after pneumonia diagnosis. In a highly vaccinated population, prior symptomatic omicron infection within 8 months reduced pneumonia risk during reinfection. Uninfected individuals might need up-to-date vaccination to reduce pneumonia risk.