Safety and Efficacy of COVID-19 Prime-boost Vaccine in Bahrain
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT04993560 |
Recruitment Status :
Completed
First Posted : August 6, 2021
Last Update Posted : October 26, 2021
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
Coronavirus disease 2019 (COVID-19) is potentially a deadly disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that targets the lung mainly, resulting in respiratory tract infections in humans. It has developed into a pandemic with serious global public health problems.
Recent research has shown that the new SARS-CoV-2 variants reduces the efficacy of the vaccinations and are predominantly more transmissible or infective. A few countries namely Bahrain, United Arab Emirates, and Turkey have recently started introducing a booster dose following primary two doses of the COVID-19 immunization series.
This study aims to identify which booster dose is more effective; taking a booster dose from the same vaccine initially taken or a booster dose from a different vaccine than initially taken.
Condition or disease | Intervention/treatment |
---|---|
SARS-CoV 2 Infection Covid19 | Biological: BBIBP-CorV Biological: BNT162b2 |
According to the World Health Organization COVID-19 Dashboard, the coronavirus disease 2019 pandemic, has caused over 181 million infections and more than 3 million deaths worldwide as of July 1, 2021. COVID-19 is potentially a deadly disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that targets the lung mainly resulting in respiratory tract infections in humans. This has become a serious concern for public health.
Among the currently approved COVID-19 vaccines in the Kingdom of Bahrain, BBIBP-CorV (inactivated virus) vaccine and BNT162b2 (mRNA vaccine) is being administered to the population.
Inactivated vaccines have been extensively studied. In a phase 1/2 trial, the BBIBP-CorV vaccine has shown to be generally safe against COVID-19 and induce antibody responses. However, WHO's Strategic Advisory Group of Experts (SAGE) experts have summarized information from clinical trials in Bahrain, United Arab Emirates, Egypt, Jordan, and China indicating that individuals with comorbidities and older adults (≥60 years) who received 2 doses of BBIBP-CorV have low confidence in the efficacy of preventing COVID-19.
Current clinical trials have played a key role in the approval of different COVID vaccines based on their efficacy data, however, there is still uncertainty regarding the duration of protection from these vaccines towards the COVID -19 virus. Recent evidence has shown that the new SARS-CoV-2 variants reduces the efficacy of the vaccinations and are predominantly more transmissible or infective.
A few countries namely Bahrain, United Arab Emirates, and Turkey have recently started introducing a booster dose following primary two doses of the COVID-19 immunization series. The enhanced humoral response has been seen in homologous vaccination. Heterologous vaccination has shown to significantly induce more immunogenicity than homologous vector boost, and higher or comparable to the homologous mRNA regimens. Strong humoral and immune response has also been induced by heterologous vector-mRNA boosting with an acceptable reactogenicity profile.
To our knowledge, there has been no research conducted to date on the reactogenic and immunogenetic response of a COVID-19 booster dose after completing the primary two doses of the COVID-19 immunization series. This study will compare the reactogenic and immunogenetic response of heterologous BNT162b2 booster dose after completing two doses of BBIBP-CorV vaccination versus homologous BBIBP-CorV booster after completing two doses of BBIBP-CorV vaccination.
Study Type : | Observational |
Actual Enrollment : | 305 participants |
Observational Model: | Ecologic or Community |
Time Perspective: | Cross-Sectional |
Official Title: | Comparing the Safety and Efficacy of Homologous and Heterologous COVID-19 Prime-boost Vaccination in Bahrain |
Actual Study Start Date : | July 18, 2021 |
Actual Primary Completion Date : | September 17, 2021 |
Actual Study Completion Date : | October 19, 2021 |

Group/Cohort | Intervention/treatment |
---|---|
Homologous booster
Two doses of BBIBP-CorV, followed by BBIBP-CorV
|
Biological: BBIBP-CorV
Inactivated virus COVID-19 vaccine
Other Name: Sinopharm COVID-19 vaccine |
Heterologous booster
Two doses of BBIBP-CorV, followed by BNT162b2
|
Biological: BNT162b2
mRNA-based COVID-19 vaccine
Other Name: Pfizer-BioNTech vaccine |
- Change from Baseline Immunogenicity at 8 weeks [ Time Frame: before the reception of the booster dose and on the 8th week after the reception of the booster dose ]Antigen-specific humoral immune response will be analyzed using one commercial immunoassay (S, N) and one pseudovirus neutralization assay (sVNT)
- Reactogenicity [ Time Frame: A follow-up call will be made to participants that received booster doses on day 1 and day 5. To review any adverse events a weekly phone call will be made for a total of 8 weeks from the date of recruitment. ]
The intensity of adverse events will be graded according to a 4-grade scale:
Grade 1 (mild), Grade 2 (moderate), Grade 3 (severe), and Grade 4 (life-threatening).
Reactogenicity symptoms can be:
Local: (Hardness, Itch, Pain, Warmth, Redness, and Swelling)
• Systemic: (Chills, Fatigue, Fever, Feverish, Headache, Joint pain, Malaise, Muscle ache, Nausea, Vomiting, Diarrhea)

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 21 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Sampling Method: | Probability Sample |
Inclusion Criteria:
- Adults aged ≥21yo.
- Asymptomatic 24h before the administration of booster dose.
- Has no active or previous RT-PCR lab-confirmed COVID-19 diagnosis.
- Completed three months to six months after the second dose of BBIBP-CorV.
- Have at least one Antibody test done before receiving the BBIBP-CorV booster dose OR can be done if the participant is yet to receive the BNT162b2 booster dose.
- Tested negative using Rapid Antigen Detection Test on the day of receiving the booster (positive results will confirm with RT-PCR).
- Study participants must have the ability to give informed consent.
Exclusion Criteria:
- Children aged <21yo.
- Symptomatic within 24h before the administration of booster dose.
- Has active or previous RT-PCR lab-confirmed COVID-19 diagnosis.
- Did not complete three months to six months after the second dose of BBIBP-CorV.
- Does not have at least one Antibody test done before receiving the BBIBP-CorV booster dose
- Tested positive using Rapid Antigen Detection Test on the day of receiving the booster (positive results will be confirmed with PCR).
- Patients unable to give informed consent.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04993560
Bahrain | |
Royal College of Surgeons in Ireland - Bahrain | |
Manama, Bahrain |
Principal Investigator: | Manaf AlQahtani, Dr. | Royal College of Surgeons in Ireland - Bahrain |
Responsible Party: | Royal College of Surgeons in Ireland - Medical University of Bahrain |
ClinicalTrials.gov Identifier: | NCT04993560 |
Other Study ID Numbers: |
CRT- COVID2021-143 |
First Posted: | August 6, 2021 Key Record Dates |
Last Update Posted: | October 26, 2021 |
Last Verified: | August 2021 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Monitoring, audits, and Research Ethics Committee review will be permitted and provide direct access to source data and documents. The Lead PI and the researchers assigned by him will have access to the stored data/specimens. Only the Lead PI and the researchers assigned working on this study will be eligible to obtain the data/specimens from the participants during data collection. |
Supporting Materials: |
Study Protocol Statistical Analysis Plan (SAP) Clinical Study Report (CSR) Analytic Code |
Time Frame: | Dr Manaf will act as the data custodian and is responsible for the storage, handling and quality of the study data. Data will be collected in the case report form to allow for cross referencing to check validity. Study documents (paper and electronic) will be retained in a secure (kept locked when not in use) location during and after the trial has finished. All essential documents including source documents will be retained for a period of 5 years after study completion (last patient, last study point). A label stating the date after which the documents can be destroyed will be placed on the inside front cover of the case notes of trial participants. |
Access Criteria: | Study documents (paper and electronic) will be retained in a secure (kept locked when not in use) location during and after the trial has finished. |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Safety Efficacy Prime-boost vaccine |
COVID-19 BBIBP-CorV booster BNT162b2 booster |
COVID-19 Respiratory Tract Infections Infections Pneumonia, Viral Pneumonia Virus Diseases Coronavirus Infections Coronaviridae Infections |
Nidovirales Infections RNA Virus Infections Lung Diseases Respiratory Tract Diseases Vaccines Immunologic Factors Physiological Effects of Drugs |