Reactogenicity, Safety, and Immunogenicity of Covid-19 Vaccine Booster

Phase 2

• Conditions: Covid19
• Interventions: Biological: Inactivated vaccine booster; Biological: mRNA vaccine booster; Drug: Viral vector vaccine booster; Biological: Placebo

• Registration Number: NCT04992182
• Lead Sponsor: Universidad del Desarrollo

Brief Summary

Preliminary data suggest that inactivated vaccine-induced neutralizing antibodies against SARS-CoV-2 decrease at six months after vaccination. Observational, unpublished data also indicate that vaccine effectiveness against Covid-19 wanes over time. Thus, the investigators aimed to determine the reactogenicity, safety, and immunogenicity of a homologous or heterologous booster of SARS-CoV-2 vaccines among people already immunized with an inactivated SARS-CoV-2 vaccine. The study focuses on the elderly population and healthcare workers.

Detailed Description

Not available

Study Timeline

• Study Start: 2021-07-08
• Status Verified: 2021-08
• Study First Submitted: 2021-08-02
• Study First Submitted QC: 2021-08-04
• Last Update Submitted: 2021-08-04
• Study First Posted: 2021-08-05
• Last Update Posted: 2021-08-05
• Primary Completion: 2021-08-31
• Study Completion: 2022-06-30

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 534

Inclusion Criteria

• Full immunization with CoronaVac (2 doses; 0,28) prior to April 15, 2021
• Being a resident of any of the eligible Nursing Homes (located in the Metropolitan Region of Chile)
• Healthcare workers of one of the eligible Nursing Homes.
• Healthcare workers of Hospital de Urgencia Asistencia Publica (HUAP, Santiago, Chile)

Exclusion Criteria

• Prior history of Covid-19
• Not able to consent

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Inactivated vaccine booster	Inactivated vaccine booster	One standard IM CoronaVac dose (0.5 mL)
mRNA vaccine booster	mRNA vaccine booster	One standard IM BNT162b2 dose (0.3 mL)
Viral vector vaccine booster	Viral vector vaccine booster	One standard IM ChAdOx1 dose (0.5 mL)
Placebo	Placebo	Saline solution IM (0.3 mL)

Primary Outcome Measures

Name	Time	Method
Early humoral response	Baseline (90-120 days after second dose of CoronaVac) and 15 days post booster dose	Change in SARS-CoV-2 neutralizing antibody levels
Immunogenicity	Baseline, 15, 30, 60, and 90 days post booster dose	Change in SARS-CoV-2 neutralizing antibody levels

Secondary Outcome Measures

Name	Time	Method
Reactogenicity	days 7, 28, and 3 months post booster dose	Solicited and unsolicited. Events will be assessed by scheduled visits performed by nursing home´s nurse stuff. Telephone numbers, including the PI´s cell phone will be available 24/7 for reporting any unsolicited reaction. Reporting will follow national regulations available at the Institute of Public Health web page (https://www.ispch.cl/anamed/farmacovigilancia/vacunas/como-notificar-esavi/)
Safety of booster dose	In addition to the scheduled visits mentioned in Outcome 3, Telephone numbers, including the PI´s cell phone will be available 24/7 throughout the study (1 year) for reporting any unsolicited reaction.	Number of subjects presenting serious adverse events post booster dose.

Trial Locations

Locations (2)

ELEAMs (Nursing Homes); 🇨🇱 Santiago, Chile

Hospital de Urgencia Asistencia Publica; 🇨🇱 Santiago, Chile