COVID-19Phase 2CoronaVarCLNCT05593042

Immunogenicity Evaluation of Omicron Variant-based Vaccine and a Trivalent Vaccine in Adults Against COVID-19 in Chile

A Phase 2 study testing CoronaVac®, Omicron Vaccine and Trivalent Vaccine in people with COVID-19 and Vaccines, run by Pontificia Universidad Catolica de Chile at 3 sites in Chile.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

Who is it for?: Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for: COVID-19, Vaccines
What is being tested?: CoronaVac®, Omicron Vaccine and Trivalent Vaccine
Type of treatment: Vaccines, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 551 participants
Where: 3 sitesChile
Study dates: 28 Nov 2022to 26 Oct 2023
Phase: Phase 2
Are there results?: None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 years and older
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

Adults, male or female, over 18 years of age;
Fully vaccinated against SARS-CoV-2 with two initial doses of CoronaVac® vaccine and that have received two booster doses of a different vaccine (heterologous group) or with CoronaVac® (homologous group) at least 5 months before enrollment;
Capable of understanding and signing the informed consent form;
Availability and commitment to comply with study procedures and in-person and remote appointments.

Who cannot join

Symptomatic COVID-19 diagnosed 60 days before enrollment (confirmed COVID-19 by RT-PCR or antigen test, or by being in close contact with a confirmed case);
Pregnant women (confirmed by urine pack test) or women who plan to get pregnant within the first 3 months of the study;
Known allergies to the vaccine components;
Evidence of uncontrolled metabolic, neurologic#, cardiac, pulmonary, hepatic, or renal disease. Significant changes in medical treatment or hospitalizations due to worsening conditions in the last three months are indicators of uncontrolled disease or unsuccessful adherence to the treatment;
Alteration of the immune system (neoplasms, except basal cell cancer), congenital or acquired immunodeficiencies, and uncontrolled autoimmune diseases. Significant changes in medical treatment or hospitalizations due to worsening conditions in the last three months are indicators of uncontrolled disease;
Behavioral, psychiatric, or cognitive conditions# that, according to the study physician, impair the ability to understand and cooperate with the requirements of this trial;

Show all 19Show fewer

Intake of immunosuppressants within 6 months before enrollment or prescribed to be taken within the next 2 years of the study. Antineoplastic therapy, radiation, and immunosuppressants that induce tolerance to transplants, among others, are included in this category;
Intake of corticosteroids within 3 months before enrollment or prescribed to be taken within 3 months after enrollment. The equivalent of 20 mg/day of prednisone for more than one week will be considered an immunosuppressive dose. Topical or inhaled steroids are not considered immunosuppressive drugs;
History of anatomic or functional asplenia;
Coagulation disorders such as coagulation factor deficiency, coagulopathy or platelet disorders, or a history of significant bleeding or bruising from intramuscular injections or venipunctures;
Alcohol or drug abuse reported 12 months before enrollment that caused medical, professional, or family consequences;
Have been treated with blood or immunoglobulin transfusions within 3 months before enrollment;
Have you received any live attenuated or inactivated vaccine within 28 and 14 days prior to the enrollment or planned to receive one within the first 28 days of the study;
Participation in another clinical trial 6 months before the enrollment or plan to participate in one 6 months after the enrollment in this trial;
Prior participation in a SARS-CoV-2 vaccine trial different than the CoronaVac03CL trial;
Any fever episode (body temperature ≥37.8℃) within 3 days before enrollment;
Any other condition that according to the primary care physician, could jeopardize the safety/rights of the subject or prevent him/her from completing the protocol
Alzheimer's and senile dementia are exclusion criteria.
Note: Obese and smoker participants are allowed to participate.

Trial locations and contacts

3 sites in 1 country.

Chile3 sites

Universidad del Desarrollo - Clínica Alemana
Santiago, RM
Pontificia Universidad Católica - Marcoleta Center
Santiago, Santiago Metropolitan
Universidad San Sebastián
Santiago, Santiago Metropolitan

Other trials in Chile

About this study

Official title: Phase 2, Randomized, Double-blind Study to Evaluate Immunogenicity Superiority of a Booster Dose With an Omicron or a Trivalent Vaccine Compared to CoronaVac, in Adults Immunized With Different Vaccine Schedules Against SARS-CoV-2 in Chile

Phase 2 clinical trial in adults previously vaccinated against SARS-CoV-2 in Chile with an initial schedule of two doses of CoronaVac® plus two booster doses with different vaccines. Subjects will randomly receive a third booster dose with Omicron, trivalent, or CoronaVac® vaccine. The humoral immunogenicity against COVID-19 will be compared in subjects that received the Omicron or the Trivalent vaccines with subjects that received CoronaVac® to determine the superiority of the two candidate vaccines versus CoronaVac®. Subjects will be followed for 6 months after the booster dose administration.

Read the detailed description

This study will be a phase 2 randomized, double-blind, multicenter clinical trial in fully vaccinated adults, males, and females, who have previously received an initial schedule of two doses of CoronaVac® plus two booster doses with different vaccines against SARS-CoV-2 in Chile. Two groups of participants will be included: Heterologous group: subjects who had received two booster doses with mRNA or viral vector-based vaccine); and homologous group: subjects who have received two booster doses of CoronaVac® in a previous clinical trial (CoronaVac03CL).

Subjects of the heterologous group will randomly receive a booster dose with Omicron, trivalent, or CoronaVac® vaccine. On the other hand, subjects of the homologous group will randomly receive a booster dose of Omicron or trivalent vaccine.

The humoral immunogenicity against COVID-19 will be compared in subjects of the heterologous group that will receive Omicron or trivalent vaccine with subjects that will receive CoronaVac®, to determine the superiority of the two candidate vaccines versus CoronaVac®.

Subjects will be followed for 6 months after the booster dose administration.

Conditions: COVID-19, Vaccines
Being tested: CoronaVac®, Omicron Vaccine, Trivalent Vaccine
Keywords: Clinical Trials, COVID-19, Inactivated Vaccine, Omicron Vaccine, Trivalent Vaccine
Medical subject headings: COVID-19

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

CoronaVac®Biological
Also called Inactivated SARS-CoV-2 Vaccine (Vero Cells) - Sinovac
The active ingredient is the SARS-CoV-2 virus (CZ02 strain, ancestral) grown in Vero cells and inactivated, in aluminum hydroxide. The vaccine is preservative-free, and it is packed in pre-load syringes (0.5 mL) with 600 SU/0.5mL of inactivated SARS-CoV-2.
Omicron VaccineBiological
An experimental intervention consisting of a booster dose of an inactivated Omicron variant vaccine.
The active ingredient is the SARS-CoV-2 virus (Omicron variant) grown in Vero cells and inactivated, in aluminum hydroxide. The vaccine is preservative-free, packed in a pre-load syringe, and contains one dose (0.5mL) of 1200 SU of inactivated SARS-CoV-2 Omicron variant.
Trivalent VaccineBiological
An experimental intervention consisting of a booster dose of an inactivated trivalent (CZ02 strain, ancestral, Delta, and Omicron variants) variant vaccine.
The active ingredient is the SARS-CoV-2 virus (CZ02 strain, ancestral, Delta, and Omicron variants) grown in Vero cells and inactivated, in aluminum hydroxide. The vaccine is preservative-free, and it is packed in a pre-load syringe containing one dose (0.5mL) (1200 SU of inactivated SARS-CoV-2 WT, 1200 SU of inactivated SARS-CoV-2 Delta variant, and 1200 SU of inactivated SARS-CoV-2 Omicron variant).

Study groups in NCT05593042
Study group	Role	What they receive
Heterologous group receiving CoronaVac®	Active comparator	General population that received two doses of CoronaVac® as a primary schedule of vaccination and two booster doses as part of the national vaccination schedule with mRNA or viral vector-based vaccines; and who receive a booster dose of CoronaVac® Receives: Biological: CoronaVac®
Heterologous group receiving Omicron vaccine	Experimental	General population that received two doses of CoronaVac® as a primary schedule of vaccination and two booster doses as part of the national vaccination schedule with mRNA or viral vector-based vaccines; and who receive a booster dose of Omicron vaccine Receives: Biological: Omicron Vaccine
Heterologous group receiving a trivalent vaccine	Experimental	General population that received two doses of CoronaVac® as a primary schedule of vaccination and two booster doses as part of the national vaccination schedule with mRNA or viral vector-based vaccines; and who receive a booster dose of trivalent vaccine Receives: Biological: Trivalent Vaccine
Homologous group receiving Omicron vaccine	Experimental	Participants of the CoronaVac03CL study who have received the primary regimen and two booster doses with CoronaVac® vaccine; and who receive a booster dose of Omicron vaccine Receives: Biological: Omicron Vaccine
Homologous group receiving a trivalent vaccine	Experimental	Participants of the CoronaVac03CL study who have received the primary regimen and two booster doses with CoronaVac® vaccine and who receive a booster dose of trivalent vaccine Receives: Biological: Trivalent Vaccine

What is being measured

The primary outcome is the main question the study is designed to answer.

Superiority in humoral immunogenicity of the neutralizing antibodies against the Delta and Omicron variants in response to a booster dose of the trivalent vaccine compared to CoronaVac® in adults previously immunized against SARS-CoV-2.
Differences in the humoral immunogenicity (GMT ratio >1) of the neutralizing antibodies against the Delta and Omicron variants in response to a booster dose of the trivalent vaccine compared to CoronaVac® in adults who have initially received two doses of CoronaVac® and two booster doses with vaccines against SARS-CoV-2 different from CoronaVac® (mRNA or viral vectors (heterologous group)) will be evaluated.
Measured: Up until 6 months after intervention
Superiority in humoral immunogenicity of neutralizing antibodies against the Omicron variant in response to a booster dose with the Omicron vaccine when compared with CoronaVac® in adults previously immunized against SARS-CoV-2.
Differences in the humoral immunogenicity (GMT ratio >1) of the neutralizing antibodies against the Omicron variant generated in response to a booster dose with the Omicron vaccine when compared with CoronaVac® in adults who have initially received two doses of CoronaVac® and two booster doses with vaccines against SARS-CoV-2 different from CoronaVac® (mRNA or viral vectors (heterologous group)) will be evaluated.
Measured: Up until 6 months after intervention
Non-inferiority of neutralizing antibodies against the Omicron and Delta variants generated by a booster dose of trivalent vaccine when compared to CoronaVac® in adults previously immunized against SARS-CoV-2 in a heterologous schedule.
Evaluation of the non-inferiority (seroconversion rate ≥5%) of neutralizing antibodies against the Omicron and Delta variants generated by a booster dose of trivalent vaccine when compared to CoronaVac® in adults who have initially received two doses of CoronaVac® and two booster doses with vaccines from other platforms (mRNA or viral vectors (heterologous group)).
Measured: Up until 6 months after intervention
Non-inferiority of neutralizing antibodies against the Omicron variant generated by a booster dose with Omicron vaccine when compared with CoronaVac® in adults previously immunized against SARS-CoV-2 in a heterologous schedule.
Evaluation of the non-inferiority (seroconversion rate ≥5%) of neutralizing antibodies against the Omicron variant generated by a booster dose with Omicron vaccine when compared with CoronaVac® in adults who have two doses of CoronaVac® and two booster doses with vaccines from other platforms (mRNA or viral vectors (heterologous group)).
Measured: Up until 6 months after intervention

Secondary outcomes (6)

Frequency of adverse events within the 7 and 28 days after the administration of a booster dose of Omicron, trivalent or CoronaVac® vaccines.
Evaluate whether there are differences in the frequency of adverse events within the 7 and 28 days after the administration of a booster dose of Omicron, trivalent or CoronaVac® vaccines.
Measured: 28 days after intervention
Serious adverse events (SAE) and adverse events of special interest (AESI) in participants who received a booster dose of the Omicron, trivalent, or CoronaVac® vaccines.
Follow up of serious adverse events (SAE) and adverse events of special interest (AESI) will be performed for participants who received a booster dose of the Omicron, trivalent, or CoronaVac® vaccines.
Measured: Up until 6 months after intervention
Humoral immunogenicity against the ancestral strain induced by a booster dose with Omicron vaccine or trivalent vaccine in adults previously immunized against SARS-CoV-2 in a heterologous schedule.
Evaluation of the humoral immunogenicity (GMT and seroconversion rate of neutralizing antibodies) against the ancestral strain, induced by a booster dose with Omicron vaccine or trivalent vaccine in adults who have two doses of CoronaVac® and two booster doses with vaccines from other platforms (mRNA or viral vectors (heterologous group)).
Measured: Up until 6 months after intervention
Humoral immunogenicity induced by a booster dose with Omicron or trivalent vaccine in adults previously immunized against SARS-CoV-2 in a homologous schedule.
To evaluate the humoral immunogenicity (GMT and seroconversion of neutralizing antibodies) induced by a booster dose with Omicron or trivalent vaccine in adults who have previously received four doses of CoronaVac® (homologous group) against the ancestral strain, the Omicron, and Delta variants.
Measured: Up until 6 months after intervention
Cellular immunogenicity generated, in a subgroup of participants, by the administration of a booster dose with Omicron, trivalent or CoronaVac® vaccines against the ancestral strain, the Omicron and Delta variants.
To evaluate, in a subgroup of participants, the cellular immunogenicity (T cell activation and cytokines secretion) generated by the administration of a booster dose with Omicron, trivalent or CoronaVac® vaccines against the ancestral strain, the Omicron and Delta variants.
Measured: Up until 6 months after intervention
Levels of neutralizing antibodies -and in a subgroup of subjects, the cellular immunity- against the ancestral, Omicron and Delta strains at 6 months after the intervention.
Evaluation of the levels of neutralizing antibodies in every participant and the cellular immunity in a subgroup of subjects against the ancestral strain, the Omicron and Delta variants at 6 months after the administration of a booster dose of the Omicron, trivalent or CoronaVac® vaccines.
Measured: 6 months after intervention

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

28 Nov 202226 Oct 2023

First posted25 Oct 2022
Study start28 Nov 2022
Primary completion26 Oct 2023
Study completion26 Oct 2023

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Publications (1)Papers the sponsor has linked to this study.
Other trials for COVID-19Studies of the same condition, open and under way.
More trials run by Pontificia Universidad Catolica de ChileThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 2
Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind
Who is masked: Participant, Care provider, Investigator, Outcomes assessor
Enrolment: 551 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05593042
Sponsor's protocol ID: PRO-tonCOV-2001-CL
Acronym: CoronaVarCL
Status last verified: Nov 2023
First submitted: 20 Oct 2022
Last updated: 7 Feb 2024
Results posted: No
Data monitoring committee: Yes
FDA-regulated drug: No
FDA-regulated device: No

Publications

Mendez C, Rodriguez-Guilarte L, Palacios PA, Gutierrez-Vera C, Roman F, Moreno-Tapia D, Rios M, Reyes A, Cancino FA, Otero FF, Zurita C, Rivera D, Cabrera A, Duarte LF, Urzua M, Iturriaga C, Rojas A, Perez CM, Redlich AS, Fasce RA, Fernandez J, Mora J, Ramirez E, Dominguez A, Weiskopf D, Grifoni A, Sette A, Zeng G, Meng W, Goldbatt D, Johnson M; CoronaVarCL study group; Gonzalez-Aramundiz JV, Alvarez-Figueroa MJ, Abarca K, Carreno LJ, Gonzalez PA, Kalergis AM, Penaloza HF, Bueno SM. A booster dose of an inactivated SARS-CoV-2 vaccine targeting virus variants sustains protective humoral and cellular immunity. BMC Med. 2025 Dec 15;24(1):37. doi: 10.1186/s12916-025-04535-8.
PubMed 41398275

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 7 Feb 2024. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Phase 2, Randomized, Double-blind Study to Evaluate Immunogenicity Superiority of a Booster Dose With an Omicron or a Trivalent Vaccine Compared to CoronaVac, in Adults Immunized With Different Vaccine Schedules Against SARS-CoV-2 in Chile
ClinicalTrials.gov ID: NCT05593042
Acronym / sponsor ID: CoronaVarCL / PRO-tonCOV-2001-CL
Conditions: COVID-19, Vaccines
Keywords: Clinical Trials, COVID-19, Inactivated Vaccine, Omicron Vaccine, Trivalent Vaccine
Phase: Phase 2
Study type: Interventional
Recruitment status: Completed
Enrolment: 551 participants (actual)
Lead sponsor: Pontificia Universidad Catolica de ChileUniversity, hospital or other
Collaborators: Sinovac Life Sciences Co., Ltd.
Study start: 28 Nov 2022 (actual)
Primary completion: 26 Oct 2023 (actual)
Study completion: 26 Oct 2023 (actual)
First posted: 25 Oct 2022 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Subjects will be followed for 6 months after the booster dose administration.

Study design

Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind (participant, care provider, investigator, outcomes assessor)
Number of arms: 5

Arm	Type	Receives
Heterologous group receiving CoronaVac®	Active comparator	Biological: CoronaVac®General population that received two doses of CoronaVac® as a primary schedule of vaccination and two booster doses as part of the national vaccination schedule with mRNA or viral vector-based vaccines; and who receive a booster dose of CoronaVac®
Heterologous group receiving Omicron vaccine	Experimental	Biological: Omicron VaccineGeneral population that received two doses of CoronaVac® as a primary schedule of vaccination and two booster doses as part of the national vaccination schedule with mRNA or viral vector-based vaccines; and who receive a booster dose of Omicron vaccine
Heterologous group receiving a trivalent vaccine	Experimental	Biological: Trivalent VaccineGeneral population that received two doses of CoronaVac® as a primary schedule of vaccination and two booster doses as part of the national vaccination schedule with mRNA or viral vector-based vaccines; and who receive a booster dose of trivalent vaccine
Homologous group receiving Omicron vaccine	Experimental	Biological: Omicron VaccineParticipants of the CoronaVac03CL study who have received the primary regimen and two booster doses with CoronaVac® vaccine; and who receive a booster dose of Omicron vaccine
Homologous group receiving a trivalent vaccine	Experimental	Biological: Trivalent VaccineParticipants of the CoronaVac03CL study who have received the primary regimen and two booster doses with CoronaVac® vaccine and who receive a booster dose of trivalent vaccine

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (4 listed)

Adults, male or female, over 18 years of age;
Fully vaccinated against SARS-CoV-2 with two initial doses of CoronaVac® vaccine and that have received two booster doses of a different vaccine (heterologous group) or with CoronaVac® (homologous group) at least 5 months before enrollment;
Capable of understanding and signing the informed consent form;
Availability and commitment to comply with study procedures and in-person and remote appointments.

Key exclusion criteria (19 listed)

Symptomatic COVID-19 diagnosed 60 days before enrollment (confirmed COVID-19 by RT-PCR or antigen test, or by being in close contact with a confirmed case);
Pregnant women (confirmed by urine pack test) or women who plan to get pregnant within the first 3 months of the study;
Known allergies to the vaccine components;
Evidence of uncontrolled metabolic, neurologic#, cardiac, pulmonary, hepatic, or renal disease. Significant changes in medical treatment or hospitalizations due to worsening conditions in the last three months are indicators of uncontrolled disease or unsuccessful adherence to the treatment;
Alteration of the immune system (neoplasms, except basal cell cancer), congenital or acquired immunodeficiencies, and uncontrolled autoimmune diseases. Significant changes in medical treatment or hospitalizations due to worsening conditions in the last three months are indicators of uncontrolled disease;

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
CoronaVac®Also: Inactivated SARS-CoV-2 Vaccine (Vero Cells) - SinovacThe active ingredient is the SARS-CoV-2 virus (CZ02 strain, ancestral) grown in Vero cells and inactivated, in aluminum hydroxide. The vaccine is preservative-free, and it is packed in pre-load syringes (0.5 mL) with 600 SU/0.5mL of inactivated SARS-CoV-2.	Biological	Heterologous group receiving CoronaVac®
Omicron VaccineAn experimental intervention consisting of a booster dose of an inactivated Omicron variant vaccine. The active ingredient is the SARS-CoV-2 virus (Omicron variant) grown in Vero cells and inactivated, in aluminum hydroxide. The vaccine is preservative-free, packed in a pre-load syringe, and contains one dose (0.5mL) of 1200 SU of inactivated SARS-CoV-2 Omicron variant.	Biological	Heterologous group receiving Omicron vaccine, Homologous group receiving Omicron vaccine
Trivalent VaccineAn experimental intervention consisting of a booster dose of an inactivated trivalent (CZ02 strain, ancestral, Delta, and Omicron variants) variant vaccine. The active ingredient is the SARS-CoV-2 virus (CZ02 strain, ancestral, Delta, and Omicron variants) grown in Vero cells and inactivated, in aluminum hydroxide. The vaccine is preservative-free, and it is packed in a pre-load syringe containing one dose (0.5mL) (1200 SU of inactivated SARS-CoV-2 WT, 1200 SU of inactivated SARS-CoV-2 Delta variant, and 1200 SU of inactivated SARS-CoV-2 Omicron variant).	Biological	Heterologous group receiving a trivalent vaccine, Homologous group receiving a trivalent vaccine

Primary outcome

Superiority in humoral immunogenicity of the neutralizing antibodies against the Delta and Omicron variants in response to a booster dose of the trivalent vaccine compared to CoronaVac® in adults previously immunized against SARS-CoV-2.
Time frame: Up until 6 months after intervention
Differences in the humoral immunogenicity (GMT ratio >1) of the neutralizing antibodies against the Delta and Omicron variants in response to a booster dose of the trivalent vaccine compared to CoronaVac® in adults who have initially received two doses of CoronaVac® and two booster doses with vaccines against SARS-CoV-2 different from CoronaVac® (mRNA or viral vectors (heterologous group)) will be evaluated.
Superiority in humoral immunogenicity of neutralizing antibodies against the Omicron variant in response to a booster dose with the Omicron vaccine when compared with CoronaVac® in adults previously immunized against SARS-CoV-2.
Time frame: Up until 6 months after intervention
Differences in the humoral immunogenicity (GMT ratio >1) of the neutralizing antibodies against the Omicron variant generated in response to a booster dose with the Omicron vaccine when compared with CoronaVac® in adults who have initially received two doses of CoronaVac® and two booster doses with vaccines against SARS-CoV-2 different from CoronaVac® (mRNA or viral vectors (heterologous group)) will be evaluated.
Non-inferiority of neutralizing antibodies against the Omicron and Delta variants generated by a booster dose of trivalent vaccine when compared to CoronaVac® in adults previously immunized against SARS-CoV-2 in a heterologous schedule.
Time frame: Up until 6 months after intervention
Evaluation of the non-inferiority (seroconversion rate ≥5%) of neutralizing antibodies against the Omicron and Delta variants generated by a booster dose of trivalent vaccine when compared to CoronaVac® in adults who have initially received two doses of CoronaVac® and two booster doses with vaccines from other platforms (mRNA or viral vectors (heterologous group)).
Non-inferiority of neutralizing antibodies against the Omicron variant generated by a booster dose with Omicron vaccine when compared with CoronaVac® in adults previously immunized against SARS-CoV-2 in a heterologous schedule.
Time frame: Up until 6 months after intervention
Evaluation of the non-inferiority (seroconversion rate ≥5%) of neutralizing antibodies against the Omicron variant generated by a booster dose with Omicron vaccine when compared with CoronaVac® in adults who have two doses of CoronaVac® and two booster doses with vaccines from other platforms (mRNA or viral vectors (heterologous group)).

6 secondary outcomes

Frequency of adverse events within the 7 and 28 days after the administration of a booster dose of Omicron, trivalent or CoronaVac® vaccines.
Time frame: 28 days after intervention
Serious adverse events (SAE) and adverse events of special interest (AESI) in participants who received a booster dose of the Omicron, trivalent, or CoronaVac® vaccines.
Time frame: Up until 6 months after intervention
Humoral immunogenicity against the ancestral strain induced by a booster dose with Omicron vaccine or trivalent vaccine in adults previously immunized against SARS-CoV-2 in a heterologous schedule.
Time frame: Up until 6 months after intervention
Humoral immunogenicity induced by a booster dose with Omicron or trivalent vaccine in adults previously immunized against SARS-CoV-2 in a homologous schedule.
Time frame: Up until 6 months after intervention
Cellular immunogenicity generated, in a subgroup of participants, by the administration of a booster dose with Omicron, trivalent or CoronaVac® vaccines against the ancestral strain, the Omicron and Delta variants.
Time frame: Up until 6 months after intervention
Levels of neutralizing antibodies -and in a subgroup of subjects, the cellular immunity- against the ancestral, Omicron and Delta strains at 6 months after the intervention.
Time frame: 6 months after intervention

Results and safety

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 7 Feb 2024.
Derived from this study: PubMed 41398275Mendez C, Rodriguez-Guilarte L, Palacios PA, Gutierrez-Vera C, Roman F, Moreno-Tapia D, Rios M, Reyes A, Cancino FA, Otero FF, Zurita C, Rivera D, Cabrera A, Duarte LF, Urzua M, Iturriaga C, Rojas A, Perez CM, Redlich AS, Fasce RA, Fernandez J, Mora J, Ramirez E, Dominguez A, Weiskopf D, Grifoni A, Sette A, Zeng G, Meng W, Goldbatt D, Johnson M; CoronaVarCL study group; Gonzalez-Aramundiz JV, Alvarez-Figueroa MJ, Abarca K, Carreno LJ, Gonzalez PA, Kalergis AM, Penaloza HF, Bueno SM. A booster dose of an inactivated SARS-CoV-2 vaccine targeting virus variants sustains protective humoral and cellular immunity. BMC Med. 2025 Dec 15;24(1):37. doi: 10.1186/s12916-025-04535-8.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Pablo A Gonzalez, PhD study director

Pontificia Universidad Catolica de Chile

Alexis M Kalergis, PhD study chair

Pontificia Universidad Catolica de Chile

Susan M Bueno, PhD study chair

Pontificia Universidad Catolica de Chile

3 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing CoronaVac®, Omicron Vaccine and Trivalent Vaccine in people with COVID-19 and Vaccines, run by Pontificia Universidad Catolica de Chile at 3 sites in Chile.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 7 Feb 2024. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 3 sites in Chile. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Superiority in humoral immunogenicity of the neutralizing antibodies against the Delta and Omicron variants in response to a booster dose of the trivalent vaccine compared to CoronaVac® in adults previously immunized against SARS-CoV-2. (time frame: Up until 6 months after intervention). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05593042, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Feb 2024.