Efficacy and safety of an inactivated whole-virion vaccine against COVID-19, QazCovid-in®, in healthy adults: A multicentre, randomised, single-blind, placebo-controlled phase 3 clinical trial with a 6-month follow-up

Khairullin B. Zakarya K. Orynbayev M. Abduraimov Y. Kassenov M. Sarsenbayeva G. Sultankulova K. Chervyakova O. Myrzakhmetova B. Nakhanov A. Nurpeisova A. Zhugunissov K. Assanzhanova N. Nurabayev S. Kerimbayev A. Yershebulov Z. Burashev Y. Kulmagambetov I. Davlyatshin T. Sergeeva M. Buzitskaya Z. Stukova M. Kutumbetov L.
August 2022 Elsevier Ltd

eClinicalMedicine
2022 #50

Background: Vaccination remains the primary measure to prevent the spread of the SARS-CoV-2 virus, further necessitating the use of effective licensed vaccines. Methods: From Dec 25, 2020, to July 11, 2021, we conducted a multicenter, randomised, single-blind, placebo-controlled phase 3 efficacy trial of the QazCovid-in® vaccine with a 180-day follow-up period in three clinical centres in Kazakhstan. A total of 3000 eligible participants aged 18 years or older were randomly assigned (4:1) to receive two doses of the vaccine (5 μg each, 21 days apart) or placebo administered intramuscularly. QazCovid-in® is a whole-virion formaldehyde-inactivated anti-COVID-19 vaccine, adjuvanted with aluminium hydroxide. The primary endpoint was the incidence of symptomatic cases of the SARS-CoV-2 infection confirmed by RT-PCR starting from day 14 after the first immunisation. The trial was registered with ClinicalTrials.gov NCT04691908. Findings: The QazCovid-in® vaccine was safe over the 6-month monitoring period after two intramuscular immunisations inducing only local short-lived adverse events. The concomitant diseases of participants did not affect the vaccine safety. Out of 2400 vaccinated participants, 31 were diagnosed with COVID-19; 43 COVID-19 cases were recorded in 600 placebo participants with onset of 14 days after the first dose within the 180-day observation period. Only one severe COVID-19 case was identified in a vaccine recipient with a comorbid chronic heart failure. The protective efficacy of the QazCovid-in® vaccine reached 82·0% (95% CI 71.1–88.5) within the 180-day observation period. Interpretation: Two immunisations with the inactivated QazCovid-in® vaccine achieved 82·0% (95% CI 71.1–88.5) protective efficacy against COVID-19 within a 180-day follow-up period. Funding: The work was funded by the Science Committee of the Ministry of Education and Science of Kazakhstan within the framework of the Scientific and Technical Program “Development of a vaccine against coronavirus infection COVID-19”. State registration number 0.0927.

Clinical trial , COVID-19 , Efficacy , Phase 3 , Vaccine , Virus

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Research Institute of Biological Safety Problems of the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan, Gvardeysk, Kazakhstan
Centre for Clinical Medicine and Research, Almaty, Kazakhstan
Clinical diagnostic laboratory Omikron 3D, Almaty, Kazakhstan
Smorodintsev Research Institute of Influenza, Saint Petersburg, Russian Federation

Research Institute of Biological Safety Problems of the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan
Centre for Clinical Medicine and Research
Clinical diagnostic laboratory Omikron 3D
Smorodintsev Research Institute of Influenza

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