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Clinical Trial
. 2021 Jul 17;398(10296):213-222.
doi: 10.1016/S0140-6736(21)01429-X. Epub 2021 Jul 8.

Efficacy and safety of an inactivated whole-virion SARS-CoV-2 vaccine (CoronaVac): interim results of a double-blind, randomised, placebo-controlled, phase 3 trial in Turkey

Mine Durusu Tanriover  1 , Hamdi Levent Doğanay  2 , Murat Akova  3 , Hatice Rahmet Güner  4 , Alpay Azap  5 , Sıla Akhan  6 , Şükran Köse  7 , Fatma Şebnem Erdinç  8 , Emin Halis Akalın  9 , Ömer Fehmi Tabak  10 , Hüsnü Pullukçu  11 , Özgür Batum  12 , Serap Şimşek Yavuz  13 , Özge Turhan  14 , Mustafa Taner Yıldırmak  15 , İftihar Köksal  16 , Yeşim Taşova  17 , Volkan Korten  18 , Gürdal Yılmaz  19 , Mustafa Kemal Çelen  20 , Sedat Altın  21 , İlhami Çelik  22 , Yaşar Bayındır  23 , İlkay Karaoğlan  24 , Aydın Yılmaz  19 , Aykut Özkul  25 , Hazal Gür  26 , Serhat Unal  27 ; CoronaVac Study Group
Collaborators, Affiliations
Clinical Trial

Efficacy and safety of an inactivated whole-virion SARS-CoV-2 vaccine (CoronaVac): interim results of a double-blind, randomised, placebo-controlled, phase 3 trial in Turkey

Mine Durusu Tanriover et al. Lancet. .

Erratum in

  • Department of Error.
    [No authors listed] [No authors listed] Lancet. 2022 Jan 29;399(10323):436. doi: 10.1016/S0140-6736(21)02787-2. Lancet. 2022. PMID: 35093230 Free PMC article. No abstract available.

Abstract

Background: CoronaVac, an inactivated whole-virion SARS-CoV-2 vaccine, has been shown to be well tolerated with a good safety profile in individuals aged 18 years and older in phase 1/2 trials, and provided a good humoral response against SARS-CoV-2. We present the interim efficacy and safety results of a phase 3 clinical trial of CoronaVac in Turkey.

Methods: This was a double-blind, randomised, placebo-controlled phase 3 trial. Volunteers aged 18-59 years with no history of COVID-19 and with negative PCR and antibody test results for SARS-CoV-2 were enrolled at 24 centres in Turkey. Exclusion criteria included (but were not limited to) immunosuppressive therapy (including steroids) within the past 6 months, bleeding disorders, asplenia, and receipt of any blood products or immunoglobulins within the past 3 months. The K1 cohort consisted of health-care workers (randomised in a 1:1 ratio), and individuals other than health-care workers were also recruited into the K2 cohort (randomised in a 2:1 ratio) using an interactive web response system. The study vaccine was 3 μg inactivated SARS-CoV-2 virion adsorbed to aluminium hydroxide in a 0·5 mL aqueous suspension. Participants received either vaccine or placebo (consisting of all vaccine components except inactivated virus) intramuscularly on days 0 and 14. The primary efficacy outcome was the prevention of PCR-confirmed symptomatic COVID-19 at least 14 days after the second dose in the per protocol population. Safety analyses were done in the intention-to-treat population. This study is registered with ClinicalTrials.gov (NCT04582344) and is active but no longer recruiting.

Findings: Among 11 303 volunteers screened between Sept 14, 2020, and Jan 5, 2021, 10 218 were randomly allocated. After exclusion of four participants from the vaccine group because of protocol deviations, the intention-to-treat group consisted of 10 214 participants (6646 [65·1%] in the vaccine group and 3568 [34·9%] in the placebo group) and the per protocol group consisted of 10 029 participants (6559 [65·4%] and 3470 [34·6%]) who received two doses of vaccine or placebo. During a median follow-up period of 43 days (IQR 36-48), nine cases of PCR-confirmed symptomatic COVID-19 were reported in the vaccine group (31·7 cases [14·6-59·3] per 1000 person-years) and 32 cases were reported in the placebo group (192·3 cases [135·7-261·1] per 1000 person-years) 14 days or more after the second dose, yielding a vaccine efficacy of 83·5% (95% CI 65·4-92·1; p<0·0001). The frequencies of any adverse events were 1259 (18·9%) in the vaccine group and 603 (16·9%) in the placebo group (p=0·0108) with no fatalities or grade 4 adverse events. The most common systemic adverse event was fatigue (546 [8·2%] participants in the vaccine group and 248 [7·0%] the placebo group, p=0·0228). Injection-site pain was the most frequent local adverse event (157 [2·4%] in the vaccine group and 40 [1·1%] in the placebo group, p<0·0001).

Interpretation: CoronaVac has high efficacy against PCR-confirmed symptomatic COVID-19 with a good safety and tolerability profile.

Funding: Turkish Health Institutes Association.

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Conflict of interest statement

Declaration of interests We declare no competing interests.

Figures

Figure 1
Figure 1
Trial profile *Four participants in the vaccine group received two doses of the study product; however, because they were older than 59 years on the day of randomisation, they were excluded from all safety and efficacy analyses due to protocol violation.
Figure 2
Figure 2
Cumulative incidence curves for COVID-19 cases (A) Cumulative incidence of COVID-19 in the per protocol population (assessed by analysing cases occurring 14 days or more after the second dose of vaccination). (B) Cumulative incidence of COVID-19 in the intention-to-treat population (starting immediately after randomisation).
Figure 3
Figure 3
Seropositivity of RBD-specific total antibodies in the vaccine and placebo groups 14 days after the second dose, by age and sex The participants with positive RBD-specific antibodies in the placebo group neither reported any symptoms during the follow-up nor had a laboratory confirmed diagnosis of COVID-19, probably representing cases with asymptomatic SARS-CoV-2 infection. RBD=receptor-binding domain.
Figure 4
Figure 4
Neutralising antibody titres among the subset of participants included in the immunogenicity analysis
Figure 5
Figure 5
Adverse events (A) Overall adverse events. (B) Local adverse events. (C) Systemic adverse events. p values are shown only for significant differences. See appendix (pp 10–12) for full data.
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References

    1. Brooks SK, Webster RK, Smith LE, et al. The psychological impact of quarantine and how to reduce it: rapid review of the evidence. Lancet. 2020;395:912–920. - PMC - PubMed
    1. Kniffin KM, Narayanan J, Anseel F, et al. COVID-19 and the workplace: implications, issues, and insights for future research and action. Am Psychol. 2021;76:63–77. - PubMed
    1. WHO Health inequity and the effects of COVID-19: assessing, responding to and mitigating the socioeconomic impact on health to build a better future. 2020. https://apps.who.int/iris/handle/10665/338199
    1. Dorn AV, Cooney RE, Sabin ML. COVID-19 exacerbating inequalities in the US. Lancet. 2020;395:1243–1244. - PMC - PubMed
    1. Yan ZP, Yang M, Lai CL. COVID-19 vaccines: a review of the safety and efficacy of current clinical trials. Pharmaceuticals (Basel) 2021;14:406. - PMC - PubMed

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