Coronavirus

The study, “A multicenter study to assess the effectiveness of an inactivated COVID-19 vaccine (CoronaVac, Sinovac) against hospitalized COVID-19” or the “COVID-19 Vaccine Effectiveness Study,” is an observational, prospective, test-negative design (TND) case-control study. It was conducted in three participating public tertiary COVID-19 referral hospitals in the Philippines: (1) Vicente Sotto Memorial Medical Center (VSMMC) in Cebu City; (2) Mariano Marcos Memorial Hospital & Medical Center (MMMHMC) in Batac City; and, (3) Davao Regional Medical Center in Tagum City. These institutions were chosen to represent each of the three major island groups in the Philippines – Luzon, Visayas, and Mindanao. The study’s primary objective was to determine the protective effectiveness of 2 doses of an inactivated COVID-19 vaccine (CoronaVac, Sinovac) against hospitalized virologically-confirmed SARS-CoV-2 infection. Adults ≥18 years old with fever and/or acute respiratory symptoms who were admitted to any of the three hospitals were enrolled. After informed consent was obtained, clinical and socio-demographic information were gathered with a standard case report form. Vaccination status was ascertained through vaccination cards and certificates (e.g., VaxCertPH) issued by the Department of Health (DOH), and a nasopharyngeal swab for RT-PCR was secured to determine the presence of SARS-CoV-2 infection. Participants were followed-up during their admission. Vaccine effectiveness estimates were calculated by comparing COVID-19 vaccination status against presence, severity, and clinical outcomes of patients with virologically confirmed COVID-19 infection.

The funder of this study is the Coalition for Epidemic Preparedness Innovations (CEPI), an innovative partnership between public, private, philanthropic, and civil organizations that was launched at the World Economic Forum at Davos in 2017. This coalition is geared towards the accelerated development of vaccines and other biological countermeasures against epidemic and pandemic threats for better vaccine access and equity. It was co-founded and co-funded by the Bill and Melinda Gates Foundation, the Wellcome Trust, and the governments of India and Norway, and was later joined by the European Union (2019) and the United Kingdom (2020). It is supported by several leading pharmaceutical companies, such as GSK, Merck, Johnson & Johnson, Pfizer, Sanofi, and Takeda, plus the Biotechnology Innovation Organisation. CEPI is headquartered in Oslo, Norway. The study ran for 20 months from April 2022 to November 2024.