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NCT Number: NCT05668065

Immunogenicity of Heterologous Versus Homologous Prime Boost Schedule With mRNA and Inactivated COVID-19 Vaccines

This study is a randomized, simple-blinded comparative phase III clinical trial comparing the immunogenicity of two doses Coronovac to that of a first dose of Coronovac (Sinovac, Beijing, China) followed by a booster shot with the mRNA-based BNT162b2 SARS-CoV-2 vaccine (Comirnaty, Pfizer-BioNTech).

The purpose of this study is to evaluate the superiority, safety and immunogenicity of the heterologous prime-boost CoronaVac/BNT162b2 vaccination to the homologous CoronaVac/CoronaVac regimen.

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Key information

Conditions

COVID-19 Coronaviridae Infections Coronavirus Infections Infections Lung Diseases Nidovirales Infections Pneumonia Pneumonia, Viral RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Leoni factory (Governorate of Bizerte), Bizerte, Mateur, Tunisia

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About this study

This study is a randomized simple-blinded comparative phase III clinical trial in COVID-19 vaccine naïve volunteers adults aged between 18 and 60 years. The purpose of this study is to evaluate the superiority, safety and immunogenicity of the heterologous prime-boost CoronaVac/BNT162b2 vaccination to the homologous CoronaVac/CoronaVac regimen. The study is conducted in four different sites located in the North of Tunisia.

A total of 240 eligible participants were included. Among them, the primary end point data were available for 100 participants randomly allocated to heterologous boost group versus 99 participants randomly allocated to homologous boost dose group.

Participants are assigned to receive either two injections of the CoronaVac vaccine (1st and 2nd vaccine), or CoronaVac as 1st dose and Pfizer as 2nd dose in 3 to 4 weeks interval.

A blood sample (5ml of the whole blood) is collected for each participant at the vaccination center before the first dose injection. After verifying the absence of a SARS-CoV-2 infection during the interrogation (a follow-up survey), a 2nd blood sample (5ml of whole blood) is taken for each participant at the vaccination center before the second dose injection. After the two injections, a 3rd blood sample (5ml of whole blood) will be taken for each participant between day 21 and day 35 after the second dose. Data collection and all samples are treated at Institute Pasteur of Tunis.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Acceptance to participate in the study.
  • Age: 18-60 years old.

Non-inclusion criteria:

  • Presence of disability (mainly mental disability).
  • Pregnancy.
  • Patients under immunosuppressive treatment or immunocompromised individuals.
  • Prior Covid-19 infection.

Exclusion criteria

  • Occurrence of a serious adverse event (death, anaphylactic shock, ...).
  • Subjects wishing to withdraw from the study.
  • Occurrence of a SARS-CoV-2 symptomatic infection during the follow-up period.

Treatment and study plan

CoronaVac/CoronaVac

Biological

Two doses at 21-day +/- 3 days. Each innoculation dose is 0.5 ml containing 600 SU in-house unit (equals to 3μg) of SARS-CoV-2 antigen.

CoronaVac/BNT162b2

Biological

First dose of Coronavac. Each innoculation dose is 0.5 ml containing 600 SU in-house unit (equals to 3μg) of SARS-CoV-2 antigen.

Second dose of BNT162b2 at 21-day +/- 3 days. Each dose of the Pfizer-BioNTech COVID-19 Vaccine is 0.3 ml. Each prefilled syringe contains 30 mcg of a nucleoside-modified messenger RNA (modRNA) encoding the viral spike (S) glycoprotein of SARS-CoV-2

Primary outcomes

  1. Superiority of the heterologous prime-boost immunization with mRNA vaccine after vaccination with an inactivated vaccine versus homologous immunization with inactivated vaccines

    Time frame: Between day 21 and day 35 after the second dose of vaccination

    The primary end point for immunogenicity was the serum neutralizing antibody level with a percentage of inhibition at 90% at 21-35 days after boost. A difference of 25% between groups was considered clinically relevant.

Secondary outcomes

  1. Immunogenicity parameters (Neutralizing antibody and IgG antibody titers) between day 21 and day 35

    Time frame: Between day 21 and day 35 after the second dose of vaccination

    The level of neutralizing antibodies and anti-spike IgG antibody responses

  2. Immunogenicity parameters (Neutralizing antibody and IgG antibody titers) at day 0 (at baseline)

    Time frame: At day 0 (at baseline)

    The level of neutralizing antibodies and anti-spike IgG antibody responses

  3. Immunogenicity parameters (Neutralizing antibody and IgG antibody titers) at day 21 +/- 3 days

    Time frame: At day 21 +/- 3 days after the first dose of vaccination

    The level of neutralizing antibodies and anti-spike IgG antibody responses

  4. Safety indexes of adverse reactions at day 30

    Time frame: At day 30 after the second dose of vaccination

    The incidence of adverse reactions at day 30 of the second dose of vaccination

Sponsors and collaborators

Lead sponsor

Institut Pasteur de Tunis

Other

Registry information

Official study title

Immunogenicity of Heterologous Versus Homologous Prime Boost Schedule With mRNA and Inactivated COVID-19 Vaccines: a Single-blinded, Randomized, Parallel Group Superiority Trial

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Dec 29, 2022
Registry last updated
Jan 5, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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