TY - JOUR
T1 - Protection conferred by SARS-CoV-2 infection across a spectrum of reinfection symptoms and severities
AU - Sukik, Layan
AU - Chemaitelly, Hiam
AU - Ayoub, Houssein H.
AU - Coyle, Peter
AU - Tang, Patrick
AU - Hasan, Mohammad R.
AU - Yassine, Hadi M.
AU - Al Thani, Asmaa A.
AU - Al-Kanaani, Zaina
AU - Al-Kuwari, Einas
AU - Jeremijenko, Andrew
AU - Kaleeckal, Anvar Hassan
AU - Latif, Ali Nizar
AU - Shaik, Riyazuddin Mohammad
AU - Abdul-Rahim, Hanan F.
AU - Nasrallah, Gheyath K.
AU - Al-Kuwari, Mohamed Ghaith
AU - Butt, Adeel
AU - Al-Romaihi, Hamad Eid
AU - Al-Thani, Mohamed H.
AU - Al-Khal, Abdullatif
AU - Bertollini, Roberto
AU - Abu-Raddad, Laith J.
N1 - Publisher Copyright:
© Author(s) (or their employer(s)) 2025.
PY - 2025/3/26
Y1 - 2025/3/26
N2 - Background SARS-CoV-2 infection is associated with protection against reinfection. This study analysed this protection across different reinfection symptoms and severities, comparing the preomicron and omicron eras. Methods A nationwide, matched, test-negative, case-control study was conducted in Qatar from 5 February 2020 to 12 March 2024. The preomicron analysis used a sample of 509 949 positive and 8 494 782 negative tests, while the omicron analysis included 682 257 positive and 6 904 044 negative tests. Data were sourced from Qatar's national databases for COVID-19 laboratory testing, vaccination, hospitalisation and death. Results Effectiveness of preomicron infection against preomicron reinfection was estimated at 80.9% (95% CI: 79.1% to 82.6%) for asymptomatic reinfection, 87.5% (95% CI: 86.1% to 88.9%) for symptomatic reinfection, 97.8% (95% CI: 95.7% to 98.9%) for severe COVID-19 reinfection, 100.0% (95% CI: 97.5% to 100.0%) for critical COVID-19 reinfection and 88.1% (95% CI: 50.3% to 97.2%) for fatal COVID-19 reinfection. For omicron infection against omicron reinfection, the estimates were 46.4% (95% CI: 36.9% to 54.4%) for asymptomatic reinfection, 52.8% (95% CI: 44.4% to 60.0%) for symptomatic reinfection, 100.0% (95% CI: 55.4% to 100.0%) for severe COVID-19 reinfection, 100.0% (95% CI: 15.1% to 100.0%) for critical COVID-19 reinfection, and 75.2% (95% CI: -58.8% to 97.5%) for fatal COVID-19 reinfection. Effectiveness over time since previous infection showed no discernible decline in protection against all forms of reinfection in the preomicron era, but a rapid decline against asymptomatic and symptomatic reinfections in the omicron era. Conclusions A gradient of protection against reinfection is evident, with the highest protection observed against severe forms of COVID-19. Over time, this gradient becomes more pronounced, as protection against asymptomatic and symptomatic reinfections decreases, while protection against severe outcomes remains strong.
AB - Background SARS-CoV-2 infection is associated with protection against reinfection. This study analysed this protection across different reinfection symptoms and severities, comparing the preomicron and omicron eras. Methods A nationwide, matched, test-negative, case-control study was conducted in Qatar from 5 February 2020 to 12 March 2024. The preomicron analysis used a sample of 509 949 positive and 8 494 782 negative tests, while the omicron analysis included 682 257 positive and 6 904 044 negative tests. Data were sourced from Qatar's national databases for COVID-19 laboratory testing, vaccination, hospitalisation and death. Results Effectiveness of preomicron infection against preomicron reinfection was estimated at 80.9% (95% CI: 79.1% to 82.6%) for asymptomatic reinfection, 87.5% (95% CI: 86.1% to 88.9%) for symptomatic reinfection, 97.8% (95% CI: 95.7% to 98.9%) for severe COVID-19 reinfection, 100.0% (95% CI: 97.5% to 100.0%) for critical COVID-19 reinfection and 88.1% (95% CI: 50.3% to 97.2%) for fatal COVID-19 reinfection. For omicron infection against omicron reinfection, the estimates were 46.4% (95% CI: 36.9% to 54.4%) for asymptomatic reinfection, 52.8% (95% CI: 44.4% to 60.0%) for symptomatic reinfection, 100.0% (95% CI: 55.4% to 100.0%) for severe COVID-19 reinfection, 100.0% (95% CI: 15.1% to 100.0%) for critical COVID-19 reinfection, and 75.2% (95% CI: -58.8% to 97.5%) for fatal COVID-19 reinfection. Effectiveness over time since previous infection showed no discernible decline in protection against all forms of reinfection in the preomicron era, but a rapid decline against asymptomatic and symptomatic reinfections in the omicron era. Conclusions A gradient of protection against reinfection is evident, with the highest protection observed against severe forms of COVID-19. Over time, this gradient becomes more pronounced, as protection against asymptomatic and symptomatic reinfections decreases, while protection against severe outcomes remains strong.
KW - Covid-19
KW - Innate Immunity
KW - Respiratory Infection
KW - Viral infection
UR - https://www.scopus.com/pages/publications/105001319908
U2 - 10.1136/bmjresp-2024-002718
DO - 10.1136/bmjresp-2024-002718
M3 - Article
C2 - 40139840
AN - SCOPUS:105001319908
SN - 2052-4439
VL - 12
JO - BMJ Open Respiratory Research
JF - BMJ Open Respiratory Research
IS - 1
M1 - e002718
ER -