From the European Society of Clinical Microbiology and Infectious Diseases April 25, 2022
According to a new study, administering a different type of vaccination (heterologous) for the third or “booster” dose of the first two doses results in higher vaccine efficacy than using the same (homologous) inactivated SARS-CoV-2 vaccine for all three doses. .
A new study on the national vaccination program against COVID-19 in Chile, presented at this year’s European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2022, Lisbon, 23-26 April) and published in The Lancet Global Health on 23 April, 2022, shows that giving a different type of vaccine (heterologous) for the third or “booster” dose than for the first two doses leads to better vaccine performance than using the same (homologous) inactivated SARS. CoV-2 vaccine for all three doses.
Dr. Rafael Araos from the Institute of Science and Innovation in Medicine, Clinica Alemana, Universidad del Desarrollo, Dr. Alejandro Hara and Dr. Eduardo A Undurraga from the Pontificia Universidad Católica de Chile, as well as colleagues from the Chilean Ministry of Health contributed to the study.
The study evaluated the effectiveness of CoronaVac (Sinovac Biotech), AZD1222 (Oxford-AstraZeneca) or BNT162b2 (Pfizer-BioNTech) vaccine boosters in individuals who completed a primary two-dose immunization schedule with CoronaVac, inactivated SARS-CoV-inactivated SARS-CoV which represents about half of the doses of the COVID-19 vaccine delivered worldwide, compared to the lack of vaccine. The study examines Chile’s national immunization program, where the two-dose Coronavac regimen is the most widely used.
Persons vaccinated from 2 February 2021 to the pre-determined end date of the trial, 10 November 2021, were evaluated; the team excluded individuals with probable or confirmed SARS-CoV-2 infection (RT-PCR or antigen test) on or before 2 February 2021 and individuals who received at least one dose of each COVID-19 vaccine before 2 February , 2021. They evaluate the effectiveness of the booster dose vaccine against laboratory-confirmed symptomatic cases of COVID-19 (symptomatic COVID-19) and results of COVID-19 (hospitalization, intensive care) [ICU]and death).
A total of 11,174,257 individuals were eligible for this study, of which 4,127,546 completed a primary immunization schedule (two doses) with CoronaVac and received a booster dose during the study period. 1 921 340 (46.5%) participants received heterologous booster AZD1222, 2 019 260 (48.9%) received heterologous BNT162b2 booster and 186 946 (4.5%) received homologous booster with CoronaVac.
The authors calculated an adjusted vaccine efficacy (using statistical modeling) to prevent symptomatic COVID-19 of 79% for the two-dose regimen plus CoronaVac booster, 97% for BNT162b2 booster, and 93% for AZD1222 booster. The corrected efficacy of the COVID-19 hospitalization vaccine, intensive care and death vaccine was 86%, 92% and 87% for CoronaVac booster, 96%, 96% and 97% for Pfizer-BioNTech booster and 98%, 99% and 98% for Astra Zeneca booster.
The authors explain that booster programs have been launched in different countries due to the emerging evidence of weakened immunity from two dosing regimens. Boosters are also important, as evidence shows that inactivated vaccines such as Coronavac offer lower protection than new mRNA vaccines from Pfizer-BioNTech and Moderna. Delta was the predominant circulating option in Chile during the study period.
They concluded: “Our results suggest that a third dose of Coronavac or the use of a different booster vaccine, such as Pfizer-BioNTech or Astra Zeneca vaccines in those who previously had two doses of Coronavac, provides a high level of protection against COVID-19, including severe illness and death … However, receiving a different booster dose vaccine results in a higher efficacy of the third dose of Coronavac vaccine for all outcomes, providing additional support for the mixing and combination approach. “
The authors also explain that this is one of the first studies to investigate the effectiveness of booster vaccines for inactivated SARS-CoV-2 vaccines. A recent study in Brazil1 showed that homologous and heterologous booster vaccines (BNT162b2 and AZD1222), following the CoronoVac primary vaccination schedule, are safe and immunogenic. Similarly, a phase 1-2 study in USA2 with mRNA-1273, Ad26.COV2.S, and BNT162b2 boosters found that heterologous boosters were on average more immunogenic than homologous boosters.
The Cov-Boost3 study in the United Kingdom (phase 2 trial) showed that different vaccines are safe and immunogenic when administered as boosters after a primary two-dose regimen of AZD1222 and BNT162b2, with the highest levels of antibodies achieved by mRNA boosters. .
Previous studies4 have examined the immunogenicity of the heterologous two-dose regimen of ChAdOx1 followed by mRNA vaccine and found that mixing and combining strategies are more immunogenic and offer more protection against COVID-19 than homologous two-dose strategies for this vaccine. combination.
In Chile, the government has already advised that heterologous boosters should be used as a first resort; however, humans can and have received a homologous booster as an alternative.
References:
“Efficacy of homologous and heterologous booster doses for inactivated SARS-CoV-2 vaccine: a large-scale prospective cohort study” by Alejandro Hara, Ph.D .; Dr. Eduardo A Unduraga; José R Zubizarreta, PhD; Cecilia Gonzalez, Ph.D .; Alejandra Pizarro, Ph.D .; Johanna Acevedo, MS; Catherine Leo, BSE; Fabio Paredes, Master; Tomas Bralic, MS; Veronica Vergara, MS; Marcelo Mosso, BSE; Francisco Leon, MBA; Ignacio Parot, MA; Paulina Leighton, BSE; Pamela Suarez, BSE; Dr. Juan Carlos Rios; Heriberto García-Escorza, MS and Rafael Araos, MD, April 23, 2022, The Lancet Global Health.DOI: 10.1016 / S2214-109X (22) 00112-7
“Heterologous to homologous booster vaccine against COVID-19 in previous recipients of two doses of CoronaVac COVID-19 in Brazil (RHH-001): phase 4, non-inferiority, single-blind, randomized study” by Dr Sue Ann Costa Clemens; Lily Wecks, Ph.D .; Ralph Clemens, Ph.D .; Dr. Ana Verena Almeida Mendes; Alessandra Ramos Souza, Ph.D .; Mariana BV Silveira, Ph.D .; Suzette Nascimento Farias da Guarda, Ph.D .; Dr. Maristela Miyamoto de Nobrega; Dr. Maria Isabel de Moraes Pinto; Isabella GS Gonzalez, Ph.D .; Natalia Salvador, Nurse D; Maria Miranda Franco, Ph.D .; Renata Navis de Avila Mendonsa, Ph.D .; Isabel Silva Keiroz Oliveira, Ph.D .; Dr. Bruno Solano de Freitas Souza; Mayara Fraga, Pharmacist D; Parvinder Alley, Ph.D .; Dr. Sagida Bibi; Liberty Cantrell, MSc; Wanwisa Dejnirattisai, PhD; Xinxue Liu, PhD; Juthathip Mongkolsapaya, DPhil; Dr. Piada Supasa; Gavin R Screaton, DPhil; Teresa Lambe, Ph.D. and Merin Voice, Ph.D., January 21, 2022, The Lancet.DOI: 10.1016 / S0140-6736 (22) 00094-0
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“Safety and immunogenicity of seven vaccines against COVID-19 as a third dose (booster) after two doses of ChAdOx1 nCov-19 or BNT162b2 in the United Kingdom (COV-BOOST): blinded, multicenter, randomized, controlled, phase 2 PS study” by Alas Munro, MRCPCH; Dr. Leila Giannani; Dr. Victoria Cornelius; Parvinder K Aley, PhD; Gavin Babbage, MPhil; Prof. Dr. David Baxter; Marcin Bula, FRCP; Katrina Katie, Ph.D .; Prof. Krishna Chatterjee, FRCP; Kate Dodd, MSc; Ivan Enever, bachelor[Hons]; Karishma Gokani, MBBS; Anna L. Goodman, DPhil; Christopher A. Green, DPhil; Linda Hardal, Ph.D .; John Howney, FRCGP; Alexander Hicks, Ph.D .; Dr. Agatha A van der Klauve; Jonathan Cook, MB BChir; Prof. Dr. Teresa Lambe; Prof. Vincenzo Libri, Ph.D .; Prof. Martin J. Levelin, Ph.D .; Alistair C. McGregor, FRCPath; Angela M Minassian, DPhil; Patrick Moore, MRCGP; Mehmud Mogol, MBBS; Yama F Mujadi, MSc; Jennifer Murira, BM; Osanlu, FRCP; Rostam Osanlu, MBChB; Daniel R. Owens, MRCPCH; Michaela Paquar, MBBS; Adrian Palfreiman, FRCP; Daniel Pan, MRCP; Tommy Rampling, DPhil; Karen Regan, Bachelor; Stephen Sich, BA; Joe Solkeld, BMBS; Prof. Dinesh Saralaya, PhD; Sunil Sharma, FRCPath; Ray Sheridan, MRCP; Ann Sturdy, MBBS; Prof. Dr. Emma C. Thomson; Shirley Todd, MSc; Prof. Chris Tuelves, Ph.D .; Prof. Robert C. Reed, Ph.D .; Dr. Sue Charlton; Basam Khalis, Ph.D .; Prof. Mary Ramsey, FFPH; Prof. Nick Andrews, Ph.D .; Prof. Jonathan S. Nguyen-Van-Tam, DM; Prof. Matthew D. Snape, Ph.D .; Xinxue Liu, PhD and Prof. Saul N Faust, PhD on behalf of the COV-BOOST Study Group, 2 December 2021, The Lancet.DOI: 10.1016 / S0140-6736 (21) 02717-3
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