A Stepped-wedge Cluster Randomized Trial to Assess the Effectiveness of the Use of the Adsorbed COVID-19 (Inactivated) Vaccine Manufactured by Sinovac

Butantan Institute1 site in 1 country27,711 target enrollmentFebruary 7, 2021

ConditionsCovid19

Overview

Phase: Phase 4
Intervention: Not specified
Conditions: Covid19
Sponsor: Butantan Institute
Enrollment: 27711
Locations: 1
Primary Endpoint: Incidence of COVID-19 cases after two-doses immunization schedule in clusters in the first quarter of study
Status: Completed
Last Updated: 2 years ago

Overview Investigators Eligibility Criteria Outcomes Sites Similar Trials

Overview

Brief Summary

This is a stepped-wedge cluster randomized trial to assess effectiveness of Sinovac's Adsorbed COVID-19 (Inactivated) vaccine. Residents in the urban area of a municipality are eligible to participate. The city was divided in clusters and those cluster were grouped to determine the offer of vaccination in four steps. The vaccine will be offered to adults (18 years old and above) according to the location of their homes in a cluster. The vaccine schedule is two doses with four-weeks interval. Baseline samples to determine previous immunity will be collected before vaccination.

Cases of COVID-19 reported in the city will be recorded according to the WHO clinical progression scale. Comparison of periods before and after vaccination and relation to immunization coverage will be considered for the assessment of effectiveness in the clusters and groups of clusters.

Registry

clinicaltrials.gov

Start Date

February 7, 2021

End Date

July 20, 2023

Last Updated

2 years ago

Study Type

Interventional

Study Design

Parallel

Sex

All

Investigators

Sponsor

Butantan Institute

Responsible Party

Sponsor

Eligibility Criteria

Inclusion Criteria

•Adults 18 years of age or older;
•Resident in the study area;
•Show voluntary intention to participate in the study, documented by the informed consent form signed by participant.

Exclusion Criteria

•For females: Pregnancy (confirmed by positive beta-hCG test), breastfeeding or intent to engage in sexual relations with reproductive intent without use of birth control methods in the three months following vaccination;
•Evidence of uncontrolled neurological, cardiac, pulmonary, hepatic or renal disease, according to anamnesis or physical examination. Significant changes in treatment or hospitalizations due to worsening of the condition in the last three months are indicators of uncontrolled disease;
•Diseases with impaired immune system including: neoplasms (except basal cell carcinoma), congenital or acquired immunodeficiencies and autoimmune diseases not controlled according to anamnesis or physical examination. Significant changes in treatment or hospitalizations due to worsening of the condition in the last three months are indicators of uncontrolled disease;
•Behavioral, cognitive or psychiatric disease that, in the opinion of the principal investigator or his or her representative physician, affects the participant's ability to understand and cooperate with all study protocol requirements;
•Any alcohol or drug abuse over the 12 months prior to enrollment in the study that has caused medical, professional or family problems, indicated by clinical history;
•History of severe allergic reactions or anaphylaxis to the study vaccine or to components thereof;
•History of asplenia;
•Participation in another clinical trial with an investigational product in the six months prior to enrollment in the study or planned participation in another clinical trial within the two years following enrollment;
•Previous participation in a study to evaluate a COVID-19 vaccine or prior exposure to a COVID-19 vaccine;
•Use of immunosuppressant therapy regimens within the six months prior to enrollment in the study for planned use within the two years following enrollment. Immunosuppressant therapy regimens include: antineoplastic chemotherapy, radiation therapy and immunosuppressants to induce transplant tolerance, among others.

Outcomes

Primary Outcomes

Incidence of COVID-19 cases after two-doses immunization schedule in clusters in the first quarter of study

Time Frame: Thirteen weeks after the beginning of study vaccination

Number of virologically-confirmed symptomatic COVID-19 six weeks after beginning of study vaccination up to thirteen weeks

Secondary Outcomes

Incidence of hospitalization and death due to COVID-19 after two-doses immunization schedule in clusters(One year after the beginning of study vaccination)
Frequency of severe COVID-19 cases(From first vaccination up to one year after first dose)
Incidence of COVID-19 cases after two-doses immunization schedule in clusters according to pre-existing SARS-CoV-2 antibodies(One year after the beginning of study vaccination)
Frequency of adverse events of special interest after immunization(From first vaccination up to one year after first dose)
Incidence of COVID-19 cases after two-doses immunization schedule in clusters according to immunization status(One year after the beginning of study vaccination)
Change in average number of reported COVID-19 cases in the study area in comparison to other neighboring cities(One year after the beginning of study vaccination)
Medically-attended adverse reactions to the study vaccine(One week after each vaccination)
Adherence to vaccination schedule(Six weeks after the beginning of study vaccination of the corresponding cluster)
Incidence of COVID-19 cases after two-doses immunization schedule in clusters up to one year of study(One year after the beginning of study vaccination)
Incidence of COVID-19 cases after two-doses immunization schedule in clusters according to immunization coverage(One year after the beginning of study vaccination)
Acceptability of the study vaccine(Two weeks after the beginning of study vaccination of the corresponding cluster)