Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections

Heba N Altarawneh; Hiam Chemaitelly; Houssein H Ayoub; Patrick Tang; Mohammad R Hasan; Hadi M Yassine; Hebah A Al-Khatib; Maria K Smatti; Peter Coyle; Zaina Al-Kanaani; Einas Al-Kuwari; Andrew Jeremijenko; Anvar H Kaleeckal; Ali N Latif; Riyazuddin M Shaik; Hanan F Abdul-Rahim; Gheyath K Nasrallah; Mohamed G Al-Kuwari; Adeel A Butt; Hamad E Al-Romaihi; Mohamed H Al-Thani; Abdullatif Al-Khal; Roberto Bertollini; Laith J Abu-Raddad

doi:10.1056/NEJMoa2203965

Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections

N Engl J Med. 2022 Jul 7;387(1):21-34. doi: 10.1056/NEJMoa2203965. Epub 2022 Jun 15.

Authors

Heba N Altarawneh¹, Hiam Chemaitelly¹, Houssein H Ayoub¹, Patrick Tang¹, Mohammad R Hasan¹, Hadi M Yassine¹, Hebah A Al-Khatib¹, Maria K Smatti¹, Peter Coyle¹, Zaina Al-Kanaani¹, Einas Al-Kuwari¹, Andrew Jeremijenko¹, Anvar H Kaleeckal¹, Ali N Latif¹, Riyazuddin M Shaik¹, Hanan F Abdul-Rahim¹, Gheyath K Nasrallah¹, Mohamed G Al-Kuwari¹, Adeel A Butt¹, Hamad E Al-Romaihi¹, Mohamed H Al-Thani¹, Abdullatif Al-Khal¹, Roberto Bertollini¹, Laith J Abu-Raddad¹

Affiliation

¹ From the Infectious Disease Epidemiology Group and the World Health Organization Collaborating Center for Disease Epidemiology Analytics on HIV/AIDS, Sexually Transmitted Infections, and Viral Hepatitis, Weill Cornell Medicine-Qatar, Cornell University, Education City (H.N.A., H.C., L.J.A.-R.), the Mathematics Program, Department of Mathematics, Statistics, and Physics, College of Arts and Sciences (H.H.A.), the Biomedical Research Center (H.M.Y., H.A.A.-K., M.K.S., P.C., G.K.N.), and the Departments of Biomedical Science (H.M.Y., H.A.A.-K., M.K.S., G.K.N.) and Public Health (H.F.A.-R., L.J.A.-R.), College of Health Sciences, QU Health, Qatar University, the Department of Pathology, Sidra Medicine (P.T., M.R.H.), Hamad Medical Corporation (P.C., Z.A.-K., E.A.-K., A.J., A.H.K., A.N.L., R.M.S., A.A.B., A.A.-K.), Primary Health Care Corporation (M.G.A.-K.), and the Ministry of Public Health (H.E.A.-R., M.H.A.-T., R.B.) - all in Doha, Qatar; the Departments of Population Health Sciences (H.N.A., H.C., A.A.B., L.J.A.-R.) and Medicine (A.A.B.), Weill Cornell Medicine, Cornell University, New York; and the Wellcome-Wolfson Institute for Experimental Medicine, Queens University, Belfast, United Kingdom (P.C.).

Abstract

Background: The protection conferred by natural immunity, vaccination, and both against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with the BA.1 or BA.2 sublineages of the omicron (B.1.1.529) variant is unclear.

Methods: We conducted a national, matched, test-negative, case-control study in Qatar from December 23, 2021, through February 21, 2022, to evaluate the effectiveness of vaccination with BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna), natural immunity due to previous infection with variants other than omicron, and hybrid immunity (previous infection and vaccination) against symptomatic omicron infection and against severe, critical, or fatal coronavirus disease 2019 (Covid-19).

Results: The effectiveness of previous infection alone against symptomatic BA.2 infection was 46.1% (95% confidence interval [CI], 39.5 to 51.9). The effectiveness of vaccination with two doses of BNT162b2 and no previous infection was negligible (-1.1%; 95% CI, -7.1 to 4.6), but nearly all persons had received their second dose more than 6 months earlier. The effectiveness of three doses of BNT162b2 and no previous infection was 52.2% (95% CI, 48.1 to 55.9). The effectiveness of previous infection and two doses of BNT162b2 was 55.1% (95% CI, 50.9 to 58.9), and the effectiveness of previous infection and three doses of BNT162b2 was 77.3% (95% CI, 72.4 to 81.4). Previous infection alone, BNT162b2 vaccination alone, and hybrid immunity all showed strong effectiveness (>70%) against severe, critical, or fatal Covid-19 due to BA.2 infection. Similar results were observed in analyses of effectiveness against BA.1 infection and of vaccination with mRNA-1273.

Conclusions: No discernable differences in protection against symptomatic BA.1 and BA.2 infection were seen with previous infection, vaccination, and hybrid immunity. Vaccination enhanced protection among persons who had had a previous infection. Hybrid immunity resulting from previous infection and recent booster vaccination conferred the strongest protection. (Funded by Weill Cornell Medicine-Qatar and others.).

MeSH terms

2019-nCoV Vaccine mRNA-1273* / immunology
2019-nCoV Vaccine mRNA-1273* / therapeutic use
BNT162 Vaccine* / immunology
BNT162 Vaccine* / therapeutic use
COVID-19* / immunology
COVID-19* / prevention & control
COVID-19* / virology
Case-Control Studies
Humans
Immunity, Innate* / immunology
Immunization*
Immunization, Secondary
Recurrence
SARS-CoV-2* / immunology
Vaccination

Substances

2019-nCoV Vaccine mRNA-1273
BNT162 Vaccine

Supplementary concepts

SARS-CoV-2 variants