Recent symptomatic Omicron infection reduced COVID-19 pneumonia risk during reinfection: A computed tomography-based
Yulan Zheng1, Shijun Jia2, Lu Tang3
1Department of Respiratory and Critical Care Medicine, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, China.
Objectives:
SARS-CoV-2 infection could cause persistent lung injury or indicate potential genetic susceptibilities. Although 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 computed tomography (CT) screening.
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.
Insights
Previous symptomatic Omicron infection significantly reduced pneumonia risk during reinfection in a highly vaccinated cohort. Uninfected individuals should maintain up-to-date vaccinations to lower their risk of developing pneumonia.
Area of Science:
- Infectious Diseases
- Pulmonology
- Vaccinology
Background:
- SARS-CoV-2 infection can lead to persistent lung injury and may indicate genetic predispositions.
- Hybrid immunity from infection offers protection against severe COVID-19, but the impact of recent infection on pneumonia risk during reinfection is not well understood, especially with limited viral and chest CT screening.
Purpose of the Study:
- To investigate whether recent symptomatic SARS-CoV-2 infection reduces the risk of developing pneumonia during subsequent Omicron variant reinfections.
- To assess the long-term lung health outcomes in patients who experienced pneumonia following COVID-19.
Main Methods:
- A cohort of 15,598 fully vaccinated and boosted patients with symptomatic COVID-19 and chest CT scans during the Omicron BF.7 wave (Dec 2022-Jan 2023) were followed through the Omicron XBB.1.5 wave (May-Aug 2023).
- A control group of 17,968 second-wave patients with COVID-19 and chest CT scans, without prior symptomatic infection, were enrolled.
- Pneumonia incidence and residual lung abnormalities on CT scans were compared between groups.
Main Results:
- 19.6% of first-wave patients developed pneumonia.
- Among reinfected patients in the second wave, only 0.2% developed pneumonia, significantly lower than the 1.7% incidence in first-time infected controls (adjusted relative risk: 0.11).
- 1.3% of first-wave pneumonia survivors had residual lung abnormalities on follow-up CT scans within 8 months.
Conclusions:
- In a highly vaccinated population, prior symptomatic Omicron infection within an 8-month period substantially reduced the risk of pneumonia during reinfection.
- Maintaining up-to-date vaccination is recommended for uninfected individuals to mitigate pneumonia risk.
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