Population immunity of natural infection, primary-series vaccination, and booster vaccination in Qatar during the COVID-19 pandemic: an observational study

Suelen H Qassim; Hiam Chemaitelly; Houssein H Ayoub; Peter Coyle; Patrick Tang; Hadi M Yassine; Asmaa A Al Thani; Hebah A Al-Khatib; Mohammad R Hasan; 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

doi:10.1016/j.eclinm.2023.102102

Population immunity of natural infection, primary-series vaccination, and booster vaccination in Qatar during the COVID-19 pandemic: an observational study

EClinicalMedicine. 2023 Jul 20:62:102102. doi: 10.1016/j.eclinm.2023.102102. eCollection 2023 Aug.

Authors

Suelen H Qassim^{1

2

3}, Hiam Chemaitelly^{1

2

3}, Houssein H Ayoub⁴, Peter Coyle^{5

6

7}, Patrick Tang⁸, Hadi M Yassine^{6

9}, Asmaa A Al Thani^{6

9}, Hebah A Al-Khatib^{6

9}, Mohammad R Hasan⁸, Zaina Al-Kanaani⁵, Einas Al-Kuwari⁵, Andrew Jeremijenko⁵, Anvar Hassan Kaleeckal⁵, Ali Nizar Latif⁵, Riyazuddin Mohammad Shaik⁵, Hanan F Abdul-Rahim¹⁰, Gheyath K Nasrallah^{6

9}, Mohamed Ghaith Al-Kuwari¹¹, Adeel A Butt^{3

5

12}, Hamad Eid Al-Romaihi¹³, Mohamed H Al-Thani¹³, Abdullatif Al-Khal⁵, Roberto Bertollini¹³, Laith J Abu-Raddad^{1

2

3

10

14}

Affiliations

¹ Infectious Disease Epidemiology Group, Weill Cornell Medicine-Qatar, Cornell University, Doha, Qatar.
² World Health Organization Collaborating Centre for Disease Epidemiology Analytics on HIV/AIDS, Sexually Transmitted Infections, and Viral Hepatitis, Weill Cornell Medicine-Qatar, Cornell University, Qatar Foundation - Education City, Doha, Qatar.
³ Department of Population Health Sciences, Weill Cornell Medicine, Cornell University, New York, NY, USA.
⁴ Mathematics Program, Department of Mathematics, Statistics, and Physics, College of Arts and Sciences, Qatar University, Doha, Qatar.
⁵ Hamad Medical Corporation, Doha, Qatar.
⁶ Biomedical Research Center, Member of QU Health, Qatar University, Doha, Qatar.
⁷ Wellcome-Wolfson Institute for Experimental Medicine, Queens University, Belfast, United Kingdom.
⁸ Department of Pathology, Sidra Medicine, Doha, Qatar.
⁹ Department of Biomedical Science, College of Health Sciences, Member of QU Health, Qatar University, Doha, Qatar.
¹⁰ Department of Public Health, College of Health Sciences, QU Health, Qatar University, Doha, Qatar.
¹¹ Primary Health Care Corporation, Doha, Qatar.
¹² Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY, USA.
¹³ Ministry of Public Health, Doha, Qatar.
¹⁴ College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.

Abstract

Background: Waning of natural infection protection and vaccine protection highlight the need to evaluate changes in population immunity over time. Population immunity of previous SARS-CoV-2 infection or of COVID-19 vaccination are defined, respectively, as the overall protection against reinfection or against breakthrough infection at a given point in time in a given population.

Methods: We estimated these population immunities in Qatar's population between July 1, 2020 and November 30, 2022, to discern generic features of the epidemiology of SARS-CoV-2. Effectiveness of previous infection, mRNA primary-series vaccination, and mRNA booster (third-dose) vaccination in preventing infection were estimated, month by month, using matched, test-negative, case-control studies.

Findings: Previous-infection effectiveness against reinfection was strong before emergence of Omicron, but declined with time after a wave and rebounded after a new wave. Effectiveness dropped after Omicron emergence from 88.3% (95% CI: 84.8-91.0%) in November 2021 to 51.0% (95% CI: 48.3-53.6%) in December 2021. Primary-series effectiveness against infection was 84.0% (95% CI: 83.0-85.0%) in April 2021, soon after introduction of vaccination, before waning gradually to 52.7% (95% CI: 46.5-58.2%) by November 2021. Effectiveness declined linearly by ∼1 percentage point every 5 days. After Omicron emergence, effectiveness dropped from 52.7% (95% CI: 46.5-58.2%) in November 2021 to negligible levels in December 2021. Booster effectiveness dropped after Omicron emergence from 83.0% (95% CI: 65.6-91.6%) in November 2021 to 32.9% (95% CI: 26.7-38.5%) in December 2021, and continued to decline thereafter. Effectiveness of previous infection and vaccination against severe, critical, or fatal COVID-19 were generally >80% throughout the study duration.

Interpretation: High population immunity against infection may not be sustained beyond a year, but population immunity against severe COVID-19 is durable with slow waning even after Omicron emergence.

Funding: The Biomedical Research Program and the Biostatistics, Epidemiology, and the Biomathematics Research Core, both at Weill Cornell Medicine-Qatar, Ministry of Public Health, Hamad Medical Corporation, Sidra Medicine, Qatar Genome Programme, Qatar University Biomedical Research Center, and Qatar University Internal Grant ID QUCG-CAS-23/24-114.

Keywords: COVID-19; Epidemiology; Immunity; Natural infection; Test-negative; Vaccine.