Efficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variant
<p><strong>Background</strong></p> Assessment of the safety and efficacy of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different populations is essential, as is investigation of the efficacy of the vaccines against emerging SARS-CoV-2...
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| Format: | Journal article |
| Language: | English |
| Published: |
Massachusetts Medical Society
2021
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| _version_ | 1826263122507202560 |
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| author | Madhi, SA Baillie, V Cutland, CL Voysey, M Koen, AL Fairlie, L Padayachee, SD Dheda, K Barnabas, SL Bhorat, QE Briner, C Kwatra, G Ahmed, K Aley, P Bhikha, S Bhiman, JN Bhorat, AE du Plessis, J Esmail, A Groenewald, M Horne, E Hwa, S-H Jose, A Lambe, T Laubscher, M Malahleha, M Masenya, M Masilela, M McKenzie, S Molapo, K Moultrie, A Oelofse, S Patel, F Pillay, S Rhead, S Rodel, H Rossouw, L Taoushanis, C Tegally, H Thombrayil, A van Eck, S Wibmer, CK Durham, NM Kelly, EJ Villafana, TL Gilbert, S Pollard, AJ de Oliveira, T Moore, PL Sigal, A Izu, A |
| author2 | NGS-SA Group |
| author_facet | NGS-SA Group Madhi, SA Baillie, V Cutland, CL Voysey, M Koen, AL Fairlie, L Padayachee, SD Dheda, K Barnabas, SL Bhorat, QE Briner, C Kwatra, G Ahmed, K Aley, P Bhikha, S Bhiman, JN Bhorat, AE du Plessis, J Esmail, A Groenewald, M Horne, E Hwa, S-H Jose, A Lambe, T Laubscher, M Malahleha, M Masenya, M Masilela, M McKenzie, S Molapo, K Moultrie, A Oelofse, S Patel, F Pillay, S Rhead, S Rodel, H Rossouw, L Taoushanis, C Tegally, H Thombrayil, A van Eck, S Wibmer, CK Durham, NM Kelly, EJ Villafana, TL Gilbert, S Pollard, AJ de Oliveira, T Moore, PL Sigal, A Izu, A |
| author_sort | Madhi, SA |
| collection | OXFORD |
| description | <p><strong>Background</strong></p>
Assessment of the safety and efficacy of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different populations is essential, as is investigation of the efficacy of the vaccines against emerging SARS-CoV-2 variants of concern, including the B.1.351 (501Y.V2) variant first identified in South Africa.
<p><strong>Methods</strong></p>
We conducted a multicenter, double-blind, randomized, controlled trial to assess the safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) in people not infected with the human immunodeficiency virus (HIV) in South Africa. Participants 18 to less than 65 years of age were assigned in a 1:1 ratio to receive two doses of vaccine containing 5×1010 viral particles or placebo (0.9% sodium chloride solution) 21 to 35 days apart. Serum samples obtained from 25 participants after the second dose were tested by pseudovirus and live-virus neutralization assays against the original D614G virus and the B.1.351 variant. The primary end points were safety and efficacy of the vaccine against laboratory-confirmed symptomatic coronavirus 2019 illness (Covid-19) more than 14 days after the second dose.
<p><strong>Results</strong></p>
Between June 24 and November 9, 2020, we enrolled 2026 HIV-negative adults (median age, 30 years); 1010 and 1011 participants received at least one dose of placebo or vaccine, respectively. Both the pseudovirus and the live-virus neutralization assays showed greater resistance to the B.1.351 variant in serum samples obtained from vaccine recipients than in samples from placebo recipients. In the primary end-point analysis, mild-to-moderate Covid-19 developed in 23 of 717 placebo recipients (3.2%) and in 19 of 750 vaccine recipients (2.5%), for an efficacy of 21.9% (95% confidence interval [CI], −49.9 to 59.8). Among the 42 participants with Covid-19, 39 cases (95.1% of 41 with sequencing data) were caused by the B.1.351 variant; vaccine efficacy against this variant, analyzed as a secondary end point, was 10.4% (95% CI, −76.8 to 54.8). The incidence of serious adverse events was balanced between the vaccine and placebo groups.
<p><strong>Conclusions</strong></p>
A two-dose regimen of the ChAdOx1 nCoV-19 vaccine did not show protection against mild-to-moderate Covid-19 due to the B.1.351 variant. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT04444674; Pan African Clinical Trials Registry number, PACTR202006922165132. |
| first_indexed | 2024-03-06T19:46:41Z |
| format | Journal article |
| id | oxford-uuid:228a27c1-5682-4dbb-9842-b7b5b0a5fe42 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:46:41Z |
| publishDate | 2021 |
| publisher | Massachusetts Medical Society |
| record_format | dspace |
| spelling | oxford-uuid:228a27c1-5682-4dbb-9842-b7b5b0a5fe422022-03-26T11:39:29ZEfficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variantJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:228a27c1-5682-4dbb-9842-b7b5b0a5fe42EnglishSymplectic ElementsMassachusetts Medical Society2021Madhi, SABaillie, VCutland, CLVoysey, MKoen, ALFairlie, LPadayachee, SDDheda, KBarnabas, SLBhorat, QEBriner, CKwatra, GAhmed, KAley, PBhikha, SBhiman, JNBhorat, AEdu Plessis, JEsmail, AGroenewald, MHorne, EHwa, S-HJose, ALambe, TLaubscher, MMalahleha, MMasenya, MMasilela, MMcKenzie, SMolapo, KMoultrie, AOelofse, SPatel, FPillay, SRhead, SRodel, HRossouw, LTaoushanis, CTegally, HThombrayil, Avan Eck, SWibmer, CKDurham, NMKelly, EJVillafana, TLGilbert, SPollard, AJde Oliveira, TMoore, PLSigal, AIzu, ANGS-SA GroupWits-VIDA COVID Group<p><strong>Background</strong></p> Assessment of the safety and efficacy of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different populations is essential, as is investigation of the efficacy of the vaccines against emerging SARS-CoV-2 variants of concern, including the B.1.351 (501Y.V2) variant first identified in South Africa. <p><strong>Methods</strong></p> We conducted a multicenter, double-blind, randomized, controlled trial to assess the safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) in people not infected with the human immunodeficiency virus (HIV) in South Africa. Participants 18 to less than 65 years of age were assigned in a 1:1 ratio to receive two doses of vaccine containing 5×1010 viral particles or placebo (0.9% sodium chloride solution) 21 to 35 days apart. Serum samples obtained from 25 participants after the second dose were tested by pseudovirus and live-virus neutralization assays against the original D614G virus and the B.1.351 variant. The primary end points were safety and efficacy of the vaccine against laboratory-confirmed symptomatic coronavirus 2019 illness (Covid-19) more than 14 days after the second dose. <p><strong>Results</strong></p> Between June 24 and November 9, 2020, we enrolled 2026 HIV-negative adults (median age, 30 years); 1010 and 1011 participants received at least one dose of placebo or vaccine, respectively. Both the pseudovirus and the live-virus neutralization assays showed greater resistance to the B.1.351 variant in serum samples obtained from vaccine recipients than in samples from placebo recipients. In the primary end-point analysis, mild-to-moderate Covid-19 developed in 23 of 717 placebo recipients (3.2%) and in 19 of 750 vaccine recipients (2.5%), for an efficacy of 21.9% (95% confidence interval [CI], −49.9 to 59.8). Among the 42 participants with Covid-19, 39 cases (95.1% of 41 with sequencing data) were caused by the B.1.351 variant; vaccine efficacy against this variant, analyzed as a secondary end point, was 10.4% (95% CI, −76.8 to 54.8). The incidence of serious adverse events was balanced between the vaccine and placebo groups. <p><strong>Conclusions</strong></p> A two-dose regimen of the ChAdOx1 nCoV-19 vaccine did not show protection against mild-to-moderate Covid-19 due to the B.1.351 variant. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT04444674; Pan African Clinical Trials Registry number, PACTR202006922165132. |
| spellingShingle | Madhi, SA Baillie, V Cutland, CL Voysey, M Koen, AL Fairlie, L Padayachee, SD Dheda, K Barnabas, SL Bhorat, QE Briner, C Kwatra, G Ahmed, K Aley, P Bhikha, S Bhiman, JN Bhorat, AE du Plessis, J Esmail, A Groenewald, M Horne, E Hwa, S-H Jose, A Lambe, T Laubscher, M Malahleha, M Masenya, M Masilela, M McKenzie, S Molapo, K Moultrie, A Oelofse, S Patel, F Pillay, S Rhead, S Rodel, H Rossouw, L Taoushanis, C Tegally, H Thombrayil, A van Eck, S Wibmer, CK Durham, NM Kelly, EJ Villafana, TL Gilbert, S Pollard, AJ de Oliveira, T Moore, PL Sigal, A Izu, A Efficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variant |
| title | Efficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variant |
| title_full | Efficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variant |
| title_fullStr | Efficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variant |
| title_full_unstemmed | Efficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variant |
| title_short | Efficacy of the ChAdOx1 nCoV-19 Covid-19 vaccine against the B.1.351 variant |
| title_sort | efficacy of the chadox1 ncov 19 covid 19 vaccine against the b 1 351 variant |
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