WHO recommends COVID-19 Vaccine AstraZeneca as booster in revised
Good Practice Statement on the use of COVID-19 Boosters, based on latest data
BANGKOK - AstraZeneca's COVID-19 vaccine (ChAdOx1-S [Recombinant]) was highly effective at preventing Omicron-related COVID-19 severe outcomes or death when used as a first booster, irrespective of the type of vaccines previously given, with an 89% relative risk reduction. Following a second booster, protection increased further with no severe outcomes or death being observed. The data from Thailand’s Chiang Mai University and Chiang Mai Provincial Health Office, et al, was published in the International Journal of Infectious Diseases.1 In all schedules studied, a booster with COVID-19 Vaccine AstraZeneca was shown to offer comparable protection to mRNA vaccines.1
Based on the latest data, including that from the Chiang Mai University, and following advice issued by the Strategic Advisory Group of Experts (SAGE) on immunisation, the World Health Organisation (WHO) has revised its Good Practice Statement on the use of COVID-19 boosters to include the use of viral vectored vaccines, including COVID-19 Vaccine AstraZeneca, as first or second boosters as part of any COVID-19 heterologous vaccination schedule.2
WHO has also concluded that currently available data are not sufficient to support a preferential recommendation for bivalent variant-containing vaccine boosters over other currently available viral vector and mRNA vaccine boosters.3
Data from an earlier analysis of the same data set, posted as a preprint in Research Square, show that a first booster with COVID-19 Vaccine AstraZeneca was also effective at preventing COVID-19 infections due to Omicron, offering comparable protection to mRNA vaccines.4
Emeritus Professor Suwat Chariyalertsak, MD, Dr.PH, Faculty of Public Health, Chiang Mai University, Thailand, commenting on the data produced in collaboration with the Chiang Mai Provincial Health Office, said: “Our studies provide important data showing that COVID-19 Vaccine AstraZeneca and mRNA vaccines are both effective as first or second boosters in reducing the risk of Omicron-related severe COVID-19 or death when used as part of a heterologous schedule. Adopting a heterologous, or ‘mix and match’, vaccination schedule may help enhance ongoing efforts to increase population coverage of booster doses.”
John Perez, Senior Vice President, Head of Late Development, Vaccines & Immune Therapies, AstraZeneca, added: “These new data further support our expectation that additional boosters of COVID-19 Vaccine AstraZeneca can help protect against all severities of Omicron-related COVID-19 from mild symptomatic to severe disease including hospitalisation and death. COVID-19 Vaccine AstraZeneca will continue to play an important role in helping to protect against currently-circulating COVID-19 variants as part of a primary or booster vaccination schedule.”
To date, over 3 billion doses of COVID-19 Vaccine AstraZeneca have been released for supply to more than 180 countries around the world, of which over two thirds have gone to lower- or lower-middle income countries. Based on model outcomes, COVID-19 Vaccine AstraZeneca is estimated to have helped save over 6 million lives during its first year of use.5
Notes
About the Thailand studies
Two separate analyses were conducted by the Faculty of Public Health, Chiang Mai University, Thailand based on the same database, produced in collaboration with the Chiang Mai Provincial Health Office. One explored the effectiveness of first and second boosters in preventing Omicron-related severe outcomes and death (International Journal of Infectious Diseases1), and one looked at the prevention of Omicron-related infections (Research Square4).
Effectiveness of heterologous boosters in preventing Omicron-related severe outcomes and death1
The study is a retrospective cohort study on Thai residents aged 18 years or older, with laboratory confirmed SARS-CoV-2 infection during 1st October–31st December 2021 (Delta predominant) and 1st February–30th April 2022 (Omicron predominant) time periods.
Severe COVID-19 outcome was defined as requiring Invasive Mechanical Ventilation (IMV) during hospital admission or death during hospital admission.
During the Omicron-dominant period, COVID-19 Vaccine AstraZeneca was shown to be highly effective (89%) at preventing Omicron-related COVID-19 severe outcomes or death post infection when used as a first booster (HR 0.11, 95% CI 0.08-0.18) as compared to the unvaccinated group.
Effectiveness of heterologous schedules in the prevention of Omicron-related infections4
The study is a test-negative, case-controlled analysis of data designed to estimate vaccine effectiveness [VE] against SARS-CoV-2 infection (COVID-19) of various heterologous (mixed) vaccination schedules.
The study aimed to evaluate the effectiveness of heterologous three dose (primary schedule plus first booster) COVID-19 vaccine schedules during the Delta period (1 October to 31 December 2021), and heterologous three and four dose schedules (primary schedule plus first and second booster) during Omicron period (1 Feb to 10 Apr 2022). Analysis for the Delta period included 27,301 participants (2,130 test-positive and 25,171 test-negative), and for the Omicron period there were 36,170 participants (14,682 test-positive and 21,488 test-negative.)
The data showed that a fourth dose of any of the COVID-19 vaccines studied, including Vaxzevria, were 75% (95% CI 71-80%) effective in preventing Omicron infection. The VE of 73% (95% CI 48-89%) for Vaxzevria was comparable to that seen with mRNA vaccines which showed VE of 71% (mrna-1273 95% CI 59-79%; BNT162b2 95% CI 60-79%) VE was adjusted for age, gender, calendar time and preceding vaccine series type.6
COVID-19 Vaccine AstraZeneca (ChAdOx1-S [Recombinant], formerly AZD1222)
AstraZeneca COVID-19 vaccine was invented by the University of Oxford. It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.
COVID-19 Vaccine AstraZeneca is a ‘viral vector’ vaccine, which means a version of a virus that cannot cause disease is used as part of the vaccine, leaving the body knowing how to fight it if it is exposed to the real virus later. This vaccine technology has been used by scientists over the past 40 years to fight other infectious diseases such as the flu, Zika, Ebola and HIV.7
COVID-19 Vaccine AstraZeneca has an acceptable safety profile, according to clinical studies and real-world evidence from tens of millions of people globally.8-14 Based on the millions of people vaccinated with Vaxzevria, very common adverse reactions reported included: headache, nausea, myalgia, arthralgia, injection site tenderness/pain/warmth/pruritus, fatigue, malaise, pyrexia, chills.15 The majority of adverse reactions were mild to moderate in severity and usually resolved within a few days of vaccination.15 COVID-19 Vaccine AstraZeneca is licenced for COVID-19 primary vaccination schedule and first booster on top of a primary schedule in both homologous and heterologous settings.
The vaccine has been granted marketing authorisation in 34 countries and conditional or emergency use in more than 20 countries. It also has Emergency Use Listing from the World Health Organization, which accelerates the pathway to access in up to 144 countries through the COVAX Facility.
Under a sub-license agreement with AstraZeneca, the vaccine is manufactured and supplied by the Serum Institute of India under the name COVISHIELD.
AstraZeneca
AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Diseases, and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide. Please visit astrazeneca.com and follow the Company on Twitter @AstraZeneca.
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References
1. Intawong K, et al. Heterologous third and fourth dose vaccines reduce severity and mortality in COVID-19 patients during the periods of delta and omicron predominance in Thailand. International Journal of Infectious Diseases. DOI: https://doi.org/10.1016/j.ijid.2022.11.006 Available at: https://www.ijidonline.com/article/S1201-9712(22)00593-8/fulltext?dgcid=raven_jbs_aip_email Accessed: November 2022
2. WHO Good Practice Statement on the use of second booster doses for COVID-19 vaccines. Available at https://www.who.int/publications/i/item/WHO-2019-nCoV-vaccines-SAGE-good-practice-statement-second-booster. Accessed: October 2022
3. WHO Good practice statement on the use of variant-containing COVID-19 vaccines. Available at https://www.who.int/publications/i/item/WHO-2019-nCoV-Vaccines-SAGE-Variants-2022.1 Accessed: October 2022
4. Intawong, K et al. Effectiveness of heterologous third and fourth dose COVID-19 vaccine schedules for SARS-CoV-2 infection during delta and omicron predominance in Thailand: A test-negative, case-control study. The Lancet Regional Health - Southeast Asia, 2022, https://doi.org/10.1016/j.lansea.2022.100121.
5. Data estimates based on model outcomes from separate analyses conducted by Airfinity and Imperial College, United Kingdom. AstraZeneca Data on File. REF-156573, 11 July 2022
6. Centers For Disease Control and Prevention. Understanding Viral Vector COVID-19 Vaccines. Available at: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/viralvector.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fvaccines%2Fcovid-19%2Fhcp%2Fviral-vector-vaccine-basics.html. Accessed: October 2022
7. Burn, E et al, Thrombosis and thrombocytopenia after vaccination against and infection with SARS-CoV-2: a population-based cohort analysis. Available at: https://www.medrxiv.org/content/10.1101/2021.07.29.21261348v1.full. Accessed: October 2022
8. Burn, E et al, Thromboembolic Events and Thrombosis With Thrombocytopenia After COVID-19 Infection and Vaccination in Catalonia, Spain. Available at SSRN: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3886421. Accessed: October 2022
9. P. Bhuyan et al. Very rare thrombosis with thrombocytopenia after second AZD1222 dose: a global safety database analysis. Lancet. Available at: https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(21)01693-7.pdf. Accessed: October 2022
10. Laporte JR et al. Vaccines against Covid-19, venous thromboembolism, and thrombocytopenia. A population-based retrospective cohort study. Available at https://www.medrxiv.org/content/10.1101/2021.07.23.21261036v1. Accessed: October 2022
11. Voysey M, et al. Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials. The Lancet 2021; 397: 881-91. Accessed: July 2022.
12. Falsey A, et al. Phase 3 safety and efficacy of AZD1222 (ChAdOx1nCoV-19 Vaccine. NEJM. Available at: https://www.nejm.org/doi/full/10.1056/NEJMoa2105290?query=featured_coronavirus. . Accessed: October 2022
13. Flaxman A, et al. Reactogenicity and immunogenicity after a late second dose or a third dose of ChAdOx1 nCoV-19 (AZ2021D1222) in the UK: a substudy of two randomized controlled trials (COV001 and COV002). The Lancet 2021; 398: 981-90. Accessed: July 2022.
14. WHO Summary of Product Characteristics. COVID-19 Vaccine AstraZeneca. December, 2021; https://www.covax.azcovid-19.com/content/dam/azcovid/pdf/covax/who-clean-smpc-azd1222-en.pdf. Accessed: October 2022
TH-12597
Expiration Date: 11/30/2024