CoronaVac Phase 3 Trial
The double-blind, randomized, placebo-controlled phase 3 trial of the inactivated whole-virion SARS-CoV-2 vaccine developed by Sinovac, conducted across Turkey. With 24 centers, 10,218 participants, and publication in The Lancet, the trial became a milestone where Turkish clinical research capacity was proven internationally under the hardest conditions of the pandemic.
A Rapid Start Under the Pandemic
Between September 14, 2020 and January 5, 2021, 11,303 volunteers were screened and 10,218 participants were enrolled. This pace was achieved at a time when every center was contending with its own restrictions, staffing burden, and patient-care priorities. The trial was conducted under the coordination of Hacettepe University Faculty of Medicine and the Hacettepe University Vaccine Institute, with funding from the Turkish Health Institutes Association (TÜSEB).
Participants were selected from volunteers aged 18-59 with no history of COVID-19, confirmed SARS-CoV-2 negative by PCR and antibody testing. The vaccine (3 μg inactivated virion adsorbed to aluminium hydroxide) and placebo were administered intramuscularly on days 0 and 14.
K1 and K2: Cohort-Based Randomization
The trial consisted of two cohorts: in the K1 cohort, healthcare workers were randomized 1:1; in the K2 cohort, non-healthcare individuals were allocated to vaccine and placebo arms at a 2:1 ratio. Randomization was executed in real time through an interactive web response system (IWRS).
The primary efficacy outcome was the prevention of PCR-confirmed symptomatic COVID-19 at least 14 days after the second dose. Safety analyses were evaluated in the intention-to-treat population.
Vaccine : Placebo randomization
Vaccine : Placebo randomization
Real-time cohort management — our own technology platform.
Findings Published in The Lancet
95% CI 65.4-92.1 · p<0.0001. 9 vs 32 PCR-positive symptomatic cases in the vaccine vs placebo groups.
No fatal or grade 4 adverse events were observed. Any adverse event: 18.9% vaccine, 16.9% placebo.
Fatigue: 8.2% in the vaccine group vs 7.0% placebo. Most common local event was injection-site pain (2.4% vs 1.1%).
24 Centers, All of Turkey
The study centers spanned academic and training-research hospitals across Turkey — including Ankara, İstanbul, İzmir, Bursa, Adana, Antalya, Trabzon, Diyarbakır, Kayseri, Malatya, Gaziantep, Kocaeli, and Ege. Each center contributed with its own infectious diseases, chest diseases, and internal medicine teams.
January 13, 2021: The Authorization Rested on This Trial
The Turkish Medicines and Medical Devices Agency granted emergency use authorization for CoronaVac on January 13, 2021. The scientific basis of the authorization was the interim analysis data of this phase 3 trial. One day later, on January 14, 2021, Türkiye launched its national COVID-19 vaccination program with CoronaVac.
Türkiye procured more than 100 million doses of CoronaVac in total. Until the end of April 2021 it was the only vaccine available in the country, administered to tens of millions of people and forming the backbone of the national vaccination effort.
From Design to Randomization: Entirely Under the Omega Roof
No critical component of this trial was outsourced. From study design to vaccine logistics, from the electronic data capture system to randomization and telephone call systems, the entire operational and technological infrastructure ran under the Omega roof.
Study Design
Protocol design, cohort structure (K1/K2), sampling plan, and statistical methodology contribution.
Vaccine Logistics
Cold-chain distribution of vaccine and placebo to 24 centers, storage, and management of scheduling processes.
Electronic Data Capture (EDC)
CRF design, collection of all visit data from 24 centers on a single EDC platform, and validation processes.
IVRS
Randomization, dose tracking, and participant communication via the telephone call system; centralized call management.
Omega IWRS
Real-time randomization of the K1/K2 cohorts; uninterrupted operation across 10,000+ participants.
Laboratory Coordination
PCR and antibody screening workflows; sample logistics and results management synchronized across 24 centers.
Data Management
Complete, auditable management of visit, adverse event, and laboratory data for thousands of participants.
Safety Surveillance
30-minute observation, diary-based adverse event follow-up, and active surveillance over a median 43-day follow-up.
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
Tanrıöver MD, Doğanay HL, Akova M, et al. — CoronaVac Study Group. Lancet 2021; 398(10296):213-222. DOI: 10.1016/S0140-6736(21)01429-X