Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study
Abstract Background This study assessed the real-world effectiveness of the ChAdOx1 nCoV-19 vaccine in adults against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, symptomatic infection, and severe coronavirus disease 2019 (COVID-19) during periods of Beta and Delta variant...
Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2025-08-01
|
| Series: | BMC Infectious Diseases |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s12879-025-11410-7 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849329656000413696 |
|---|---|
| author | Hiam Chemaitelly Houssein H. Ayoub Peter Coyle Patrick Tang Mohammad R. Hasan Hadi M. Yassine Asmaa A. Al Thani Zaina Al-Kanaani Einas Al-Kuwari Andrew Jeremijenko Anvar Hassan Kaleeckal Ali Nizar Latif Riyazuddin Mohammad Shaik Hanan F. Abdul-Rahim Gheyath K. Nasrallah Mohamed Ghaith Al-Kuwari Adeel A. Butt Hamad Eid Al-Romaihi Mohamed H. Al-Thani Abdullatif Al-Khal Roberto Bertollini Laith J. Abu-Raddad |
| author_facet | Hiam Chemaitelly Houssein H. Ayoub Peter Coyle Patrick Tang Mohammad R. Hasan Hadi M. Yassine Asmaa A. Al Thani Zaina Al-Kanaani Einas Al-Kuwari Andrew Jeremijenko Anvar Hassan Kaleeckal Ali Nizar Latif Riyazuddin Mohammad Shaik Hanan F. Abdul-Rahim Gheyath K. Nasrallah Mohamed Ghaith Al-Kuwari Adeel A. Butt Hamad Eid Al-Romaihi Mohamed H. Al-Thani Abdullatif Al-Khal Roberto Bertollini Laith J. Abu-Raddad |
| author_sort | Hiam Chemaitelly |
| collection | DOAJ |
| description | Abstract Background This study assessed the real-world effectiveness of the ChAdOx1 nCoV-19 vaccine in adults against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, symptomatic infection, and severe coronavirus disease 2019 (COVID-19) during periods of Beta and Delta variant dominance in Qatar. Methods A national, matched, test-negative case-control study was conducted using 186,130 PCR-positive tests (cases) and 667,289 PCR-negative tests (controls) collected between January 1 and December 18, 2021. Subgroup analyses were performed to evaluate vaccine effectiveness across key strata. Results The median time between the first and second doses was 61 days (interquartile range, 56–64 days). Two-dose primary-series effectiveness was 66.0% (95% CI, 55.1–74.3%) against any SARS-CoV-2 infection and 73.0% (95% CI, 44.1–87.0%) against symptomatic infection. Effectiveness was estimated at 100% (95% CI, 64.0–100%) against any Beta variant infection and 65.3% (95% CI, 54.2–73.8%) against any Delta infection. Protection against any infection of any variant peaked at 78.4% (95% CI, 50.7–90.5%) within the first month after the second dose, gradually declining to 45.6% (95% CI, 5.5–68.7%) after 150 days. Effectiveness against severe, critical, or fatal COVID-19, irrespective of variant, was 100% (95% CI, 49.3–100%), with no vaccinated individuals progressing to severe, critical, or fatal disease after infection. Effectiveness of a single dose was 59.9% (95% CI, 51.0–67.3%) against any infection—65.0% (95% CI, 49.7–75.6%) against Beta and 55.9% (95% CI, 43.8–65.5%) against Delta—78.4% (95% CI, 60.9–88.0%) against symptomatic infection, and 100% (95% CI, 88.9–100%) against severe, critical, or fatal COVID-19. Conclusion The ChAdOx1 nCoV-19 vaccine provided substantial protection against infection and strong protection against severe outcomes during periods dominated by the Beta and Delta variants, although protection against infection waned within the first few months following the primary series. |
| format | Article |
| id | doaj-art-dfcf54cdd3a84b0796b0843bd0d29413 |
| institution | Kabale University |
| issn | 1471-2334 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Infectious Diseases |
| spelling | doaj-art-dfcf54cdd3a84b0796b0843bd0d294132025-08-20T03:47:12ZengBMCBMC Infectious Diseases1471-23342025-08-0125111310.1186/s12879-025-11410-7Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide studyHiam Chemaitelly0Houssein H. Ayoub1Peter Coyle2Patrick Tang3Mohammad R. Hasan4Hadi M. Yassine5Asmaa A. Al Thani6Zaina Al-Kanaani7Einas Al-Kuwari8Andrew Jeremijenko9Anvar Hassan Kaleeckal10Ali Nizar Latif11Riyazuddin Mohammad Shaik12Hanan F. Abdul-Rahim13Gheyath K. Nasrallah14Mohamed Ghaith Al-Kuwari15Adeel A. Butt16Hamad Eid Al-Romaihi17Mohamed H. Al-Thani18Abdullatif Al-Khal19Roberto Bertollini20Laith J. Abu-Raddad21Infectious Disease Epidemiology Group, Weill Cornell Medicine-Qatar, Qatar Foundation - Education City, Cornell UniversityMathematics Program, Department of Mathematics, Statistics and Physics, College of Arts and Sciences, Qatar UniversityHamad Medical CorporationDepartment of Pathology and Laboratory Medicine, University of British ColumbiaDepartment of Pathology and Molecular Medicine, McMaster UniversityDepartment of Biomedical Science, College of Health Sciences, QU Health, Qatar UniversityDepartment of Biomedical Science, College of Health Sciences, QU Health, Qatar UniversityHamad Medical CorporationHamad Medical CorporationHamad Medical CorporationHamad Medical CorporationHamad Medical CorporationHamad Medical CorporationDepartment of Public Health, College of Health Sciences, QU Health, Qatar UniversityDepartment of Biomedical Science, College of Health Sciences, QU Health, Qatar UniversityPrimary Health Care CorporationDepartment of Population Health Sciences, Weill Cornell Medicine, Cornell UniversityMinistry of Public HealthMinistry of Public HealthHamad Medical CorporationMinistry of Public HealthInfectious Disease Epidemiology Group, Weill Cornell Medicine-Qatar, Qatar Foundation - Education City, Cornell UniversityAbstract Background This study assessed the real-world effectiveness of the ChAdOx1 nCoV-19 vaccine in adults against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, symptomatic infection, and severe coronavirus disease 2019 (COVID-19) during periods of Beta and Delta variant dominance in Qatar. Methods A national, matched, test-negative case-control study was conducted using 186,130 PCR-positive tests (cases) and 667,289 PCR-negative tests (controls) collected between January 1 and December 18, 2021. Subgroup analyses were performed to evaluate vaccine effectiveness across key strata. Results The median time between the first and second doses was 61 days (interquartile range, 56–64 days). Two-dose primary-series effectiveness was 66.0% (95% CI, 55.1–74.3%) against any SARS-CoV-2 infection and 73.0% (95% CI, 44.1–87.0%) against symptomatic infection. Effectiveness was estimated at 100% (95% CI, 64.0–100%) against any Beta variant infection and 65.3% (95% CI, 54.2–73.8%) against any Delta infection. Protection against any infection of any variant peaked at 78.4% (95% CI, 50.7–90.5%) within the first month after the second dose, gradually declining to 45.6% (95% CI, 5.5–68.7%) after 150 days. Effectiveness against severe, critical, or fatal COVID-19, irrespective of variant, was 100% (95% CI, 49.3–100%), with no vaccinated individuals progressing to severe, critical, or fatal disease after infection. Effectiveness of a single dose was 59.9% (95% CI, 51.0–67.3%) against any infection—65.0% (95% CI, 49.7–75.6%) against Beta and 55.9% (95% CI, 43.8–65.5%) against Delta—78.4% (95% CI, 60.9–88.0%) against symptomatic infection, and 100% (95% CI, 88.9–100%) against severe, critical, or fatal COVID-19. Conclusion The ChAdOx1 nCoV-19 vaccine provided substantial protection against infection and strong protection against severe outcomes during periods dominated by the Beta and Delta variants, although protection against infection waned within the first few months following the primary series.https://doi.org/10.1186/s12879-025-11410-7COVID-19VaccineEffectivenessVaxzevriaAstrazenecaChAdOx1 nCoV-19 |
| spellingShingle | Hiam Chemaitelly Houssein H. Ayoub Peter Coyle Patrick Tang Mohammad R. Hasan Hadi M. Yassine Asmaa A. Al Thani Zaina Al-Kanaani Einas Al-Kuwari Andrew Jeremijenko Anvar Hassan Kaleeckal Ali Nizar Latif Riyazuddin Mohammad Shaik Hanan F. Abdul-Rahim Gheyath K. Nasrallah Mohamed Ghaith Al-Kuwari Adeel A. Butt Hamad Eid Al-Romaihi Mohamed H. Al-Thani Abdullatif Al-Khal Roberto Bertollini Laith J. Abu-Raddad Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study BMC Infectious Diseases COVID-19 Vaccine Effectiveness Vaxzevria Astrazeneca ChAdOx1 nCoV-19 |
| title | Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study |
| title_full | Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study |
| title_fullStr | Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study |
| title_full_unstemmed | Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study |
| title_short | Effectiveness of ChAdOx1 nCoV-19 (Vaxzevria) primary series vaccine against SARS-CoV-2 beta and delta variants: a nationwide study |
| title_sort | effectiveness of chadox1 ncov 19 vaxzevria primary series vaccine against sars cov 2 beta and delta variants a nationwide study |
| topic | COVID-19 Vaccine Effectiveness Vaxzevria Astrazeneca ChAdOx1 nCoV-19 |
| url | https://doi.org/10.1186/s12879-025-11410-7 |
| work_keys_str_mv | AT hiamchemaitelly effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT housseinhayoub effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT petercoyle effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT patricktang effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT mohammadrhasan effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT hadimyassine effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT asmaaaalthani effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT zainaalkanaani effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT einasalkuwari effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT andrewjeremijenko effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT anvarhassankaleeckal effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT alinizarlatif effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT riyazuddinmohammadshaik effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT hananfabdulrahim effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT gheyathknasrallah effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT mohamedghaithalkuwari effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT adeelabutt effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT hamadeidalromaihi effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT mohamedhalthani effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT abdullatifalkhal effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT robertobertollini effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy AT laithjaburaddad effectivenessofchadox1ncov19vaxzevriaprimaryseriesvaccineagainstsarscov2betaanddeltavariantsanationwidestudy |