Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 Gamma variant circulation in São Paulo

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Abstract

A two-dose regimen of the Oxford-AstraZeneca (ChAdOx1) Covid-19 vaccine with an inter-dose interval of three months has been implemented in many countries with restricted vaccine supply. However, there is limited evidence for the effectiveness of ChAdOx1 by dose in elderly populations in countries with high prevalence of the Gamma variant of SARS-CoV-2. Here, we estimate ChAdOx1 effectiveness by dose against the primary endpoint of RT-PCR-confirmed Covid-19, and secondary endpoints of Covid-19 hospitalization and Covid-19-related death, in adults aged ≥60 years during an epidemic with high Gamma variant prevalence in São Paulo state, Brazil using a matched, test-negative case-control study. Starting 28 days after the first dose, effectiveness of a single dose of ChAdOx1 is 33.4% (95% CI, 26.4–39.7) against Covid-19, 55.1% (95% CI, 46.6–62.2) against hospitalization, and 61.8% (95% CI, 48.9–71.4) against death. Starting 14 days after the second dose, effectiveness of the two-dose schedule is 77.9% (95% CI, 69.2–84.2) against Covid-19, 87.6% (95% CI, 78.2–92.9) against hospitalization, and 93.6% (95% CI, 81.9–97.7) against death. Completion of the ChAdOx1 vaccine schedule affords significantly increased protection over a single dose against mild and severe Covid-19 outcomes in elderly individuals during widespread Gamma variant circulation.

Abstract

Here, the authors investigate the effectiveness of the Oxford-AstraZeneca (ChAdOx1) vaccine during extensive Gamma variant SARS-CoV-2 circulation in São Paulo state, Brazil, and find that a two-dose regime is more effective than one dose against mild to severe Covid-19 outcomes in older adults.

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Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine

Fernando P Polack, Stephen J. Thomas, Nicholas R.E. Kitchin … (2023)

Abstract Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (Covid-19) have afflicted tens of millions of people in a worldwide pandemic. Safe and effective vaccines are needed urgently. Methods In an ongoing multinational, placebo-controlled, observer-blinded, pivotal efficacy trial, we randomly assigned persons 16 years of age or older in a 1:1 ratio to receive two doses, 21 days apart, of either placebo or the BNT162b2 vaccine candidate (30 μg per dose). BNT162b2 is a lipid nanoparticle–formulated, nucleoside-modified RNA vaccine that encodes a prefusion stabilized, membrane-anchored SARS-CoV-2 full-length spike protein. The primary end points were efficacy of the vaccine against laboratory-confirmed Covid-19 and safety. Results A total of 43,548 participants underwent randomization, of whom 43,448 received injections: 21,720 with BNT162b2 and 21,728 with placebo. There were 8 cases of Covid-19 with onset at least 7 days after the second dose among participants assigned to receive BNT162b2 and 162 cases among those assigned to placebo; BNT162b2 was 95% effective in preventing Covid-19 (95% credible interval, 90.3 to 97.6). Similar vaccine efficacy (generally 90 to 100%) was observed across subgroups defined by age, sex, race, ethnicity, baseline body-mass index, and the presence of coexisting conditions. Among 10 cases of severe Covid-19 with onset after the first dose, 9 occurred in placebo recipients and 1 in a BNT162b2 recipient. The safety profile of BNT162b2 was characterized by short-term, mild-to-moderate pain at the injection site, fatigue, and headache. The incidence of serious adverse events was low and was similar in the vaccine and placebo groups. Conclusions A two-dose regimen of BNT162b2 conferred 95% protection against Covid-19 in persons 16 years of age or older. Safety over a median of 2 months was similar to that of other viral vaccines. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04368728.)

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Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine

Lindsey Baden, Hana El Sahly, Brandon Essink … (2020)

Abstract Background Vaccines are needed to prevent coronavirus disease 2019 (Covid-19) and to protect persons who are at high risk for complications. The mRNA-1273 vaccine is a lipid nanoparticle–encapsulated mRNA-based vaccine that encodes the prefusion stabilized full-length spike protein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes Covid-19. Methods This phase 3 randomized, observer-blinded, placebo-controlled trial was conducted at 99 centers across the United States. Persons at high risk for SARS-CoV-2 infection or its complications were randomly assigned in a 1:1 ratio to receive two intramuscular injections of mRNA-1273 (100 μg) or placebo 28 days apart. The primary end point was prevention of Covid-19 illness with onset at least 14 days after the second injection in participants who had not previously been infected with SARS-CoV-2. Results The trial enrolled 30,420 volunteers who were randomly assigned in a 1:1 ratio to receive either vaccine or placebo (15,210 participants in each group). More than 96% of participants received both injections, and 2.2% had evidence (serologic, virologic, or both) of SARS-CoV-2 infection at baseline. Symptomatic Covid-19 illness was confirmed in 185 participants in the placebo group (56.5 per 1000 person-years; 95% confidence interval [CI], 48.7 to 65.3) and in 11 participants in the mRNA-1273 group (3.3 per 1000 person-years; 95% CI, 1.7 to 6.0); vaccine efficacy was 94.1% (95% CI, 89.3 to 96.8%; P<0.001). Efficacy was similar across key secondary analyses, including assessment 14 days after the first dose, analyses that included participants who had evidence of SARS-CoV-2 infection at baseline, and analyses in participants 65 years of age or older. Severe Covid-19 occurred in 30 participants, with one fatality; all 30 were in the placebo group. Moderate, transient reactogenicity after vaccination occurred more frequently in the mRNA-1273 group. Serious adverse events were rare, and the incidence was similar in the two groups. Conclusions The mRNA-1273 vaccine showed 94.1% efficacy at preventing Covid-19 illness, including severe disease. Aside from transient local and systemic reactions, no safety concerns were identified. (Funded by the Biomedical Advanced Research and Development Authority and the National Institute of Allergy and Infectious Diseases; COVE ClinicalTrials.gov number, NCT04470427.)

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Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

Merryn Voysey, Sue Ann Costa Clemens, Shabir Madhi … (2022)

Background A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. Methods This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. Findings Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0–75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4–97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; p interaction =0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8–80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3–4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. Interpretation ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. Funding UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D’Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca.

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Author and article information

Contributors

Julio Croda:

ORCID: http://orcid.org/0000-0002-6665-6825

julio.croda@fiocruz.br

Journal

Journal ID (nlm-ta): Nat Commun

Journal ID (iso-abbrev): Nat Commun

Title: Nature Communications

Publisher: Nature Publishing Group UK (London )

ISSN (Electronic): 2041-1723

Publication date (Electronic): 28 October 2021

Publication date PMC-release: 28 October 2021

Publication date Collection: 2021

Volume: 12

Electronic Location Identifier: 6220

Affiliations

[1 ]GRID grid.15276.37, ISNI 0000 0004 1936 8091, Department of Biostatistics, College of Public Health & Health Professions, , University of Florida, ; Gainesville, FL USA

[2 ]GRID grid.434607.2, ISNI 0000 0004 1763 3517, Barcelona Institute for Global Health, ISGlobal, ; Barcelona, Spain

[3 ]GRID grid.11899.38, ISNI 0000 0004 1937 0722, Pulmonary Division, Heart Institute (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, , Universidade de São Paulo, ; São Paulo, São Paulo Brazil

[4 ]GRID grid.47100.32, ISNI 0000000419368710, Department of Epidemiology of Microbial Diseases, , Yale School of Public Health, ; New Haven, CT USA

[5 ]Disease Control Coordination of the São Paulo State Department of Health, São Paulo, São Paulo Brazil

[6 ]Municipal Health Secretary of Manaus, Manaus, Amazonas Brazil

[7 ]Pan American Health Organization, Brasília, Distrito Federal Brazil

[8 ]GRID grid.7632.0, ISNI 0000 0001 2238 5157, Universidade de Brasília, ; Brasília, Distrito Federal Brazil

[9 ]GRID grid.47100.32, ISNI 0000000419368710, Department of Laboratory Medicine, , Yale University School of Medicine, ; New Haven, CT USA

[10 ]GRID grid.473010.1, ISNI 0000 0004 0615 3104, State University of Mato Grosso do Sul - UEMS, ; Dourados, Mato Grosso do Sul Brazil

[11 ]GRID grid.412352.3, ISNI 0000 0001 2163 5978, Universidade Federal de Mato Grosso do Sul - UFMS, ; Campo Grande, Mato Grosso do Sul Brazil

[12 ]National Institute for Science and Technology for Health Technology Assessment, Porto Alegre, Rio Grande do Sul Brazil

[13 ]Health Secretariat of the State of São Paulo, São Paulo, São Paulo Brazil

[14 ]GRID grid.168010.e, ISNI 0000000419368956, Division of Infectious Diseases and Geographic Medicine, , Stanford University, ; Stanford, CA USA

[15 ]GRID grid.15276.37, ISNI 0000 0004 1936 8091, Department of Biology, , University of Florida, ; Gainesville, FL USA

[16 ]GRID grid.15276.37, ISNI 0000 0004 1936 8091, Emerging Pathogens Institute, , University of Florida, ; Gainesville, FL USA

[17 ]GRID grid.418068.3, ISNI 0000 0001 0723 0931, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, ; Salvador, Bahia Brazil

[18 ]GRID grid.418068.3, ISNI 0000 0001 0723 0931, Fiocruz Mato Grosso do Sul, Fundação Oswaldo Cruz, ; Campo Grande, Mato Grosso do Sul Brazil

Author information

Matt D. T. Hitchings http://orcid.org/0000-0003-2327-3557

Otavio T. Ranzani http://orcid.org/0000-0002-4677-6862

Edlaine Faria de Moura Villela http://orcid.org/0000-0002-7043-2007

Mario Sergio Scaramuzzini Torres http://orcid.org/0000-0002-2050-7648

Wade Schulz http://orcid.org/0000-0002-2048-4028

Roberto Dias de Oliveira http://orcid.org/0000-0001-7996-8011

Patricia Vieira Silva http://orcid.org/0000-0001-6632-7848

Jason R. Andrews http://orcid.org/0000-0002-5967-251X

Derek A. T. Cummings http://orcid.org/0000-0002-9437-1907

Albert I. Ko http://orcid.org/0000-0001-9023-2339

Julio Croda http://orcid.org/0000-0002-6665-6825

Article

Publisher ID: 26459

DOI: 10.1038/s41467-021-26459-6

PMC ID: 8553924

PubMed ID: 34711813

SO-VID: 85aba096-0583-40db-9e1b-9d0c6c4a8f8d

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Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

History

Date received : 10 September 2021

Date accepted : 8 October 2021

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Keywords: viral infection,epidemiology

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ScienceOpen disciplines: Uncategorized

Keywords: viral infection, epidemiology

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Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 Gamma variant circulation in São Paulo

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Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine

Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

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