EClinicalMedicine (Aug 2022)

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

  • Berik Khairullin,
  • Kunsulu Zakarya,
  • Mukhit Orynbayev,
  • Yergali Abduraimov,
  • Markhabat Kassenov,
  • Gulbanu Sarsenbayeva,
  • Kulyaisan Sultankulova,
  • Olga Chervyakova,
  • Balzhan Myrzakhmetova,
  • Aziz Nakhanov,
  • Ainur Nurpeisova,
  • Kuandyk Zhugunissov,
  • Nurika Assanzhanova,
  • Sergazy Nurabayev,
  • Aslan Kerimbayev,
  • Zakir Yershebulov,
  • Yerbol Burashev,
  • Ilyas Kulmagambetov,
  • Timur Davlyatshin,
  • Maria Sergeeva,
  • Zhanna Buzitskaya,
  • Marina Stukova,
  • Lespek Kutumbetov

Journal volume & issue
Vol. 50
p. 101526

Abstract

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Summary: 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.

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