Immune Response to Third Dose of COVID-19 Vaccine in Solid Organ Transplant

Study Overview
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Brief Summary
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The Coronavirus Disease 2019 (COVID-19) pandemic has claimed over 5 million lives globally. Fortunately, a substantial and growing number of SARS-CoV-2 vaccines with very high efficacy have been developed, manufactured, and rapidly approved. Novel mRNA vaccines such as the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) have reported a stunning >94% efficacy against COVID-19. However, global access has not been equitable, with many low- and middle-income countries having no vaccine access or access under emergency use mainly to traditional inactivated SARS-CoV2-2 vaccines such as BBIBP-CorV (Sinopharm Beijing), CoronaVac (Sinovac) and BBV152 (Bharat Biotech). Emerging studies have shown that lower concentrations of neutralizing antibodies (Nab) are attained after CoronaVac than after an mRNA-based vaccine in healthy individuals. This difference seems to be more pronounced in immunocompromised patients who are at higher risk of severe COVID-19 and death from COVID-19. As such, several countries including the United States, Israel and Chile have recommended a third vaccine dose for high-risk populations. However, it is not currently known which is the best vaccine combination regarding immunogenicity, particularly in these vulnerable patients. This observational study will explore the humoral and cellular response to a SARS-CoV-2 BNT162b2 vaccine booster in solid organ transplant patients who received two previous doses of the inactivated Coronavac or two doses of BNT162b2 vaccines.

Official Title
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Immune Response to Third Dose of SARS-CoV-2 Vaccine in a Cohort of Solid Organ Transplant Recipients

Conditions
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COVID-19, SARS-CoV-2 Infection, Solid Organ Transplant, Vaccine Response Impaired

Intervention / Treatment
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* Biological: Three doses of SARS-CoV-2 BNT162b2 vaccine (observational)
* Biological: Two doses of CoronaVac and one dose of BNT162b2 SARS-CoV-2 vaccine (observational)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Solid organ transplant patients in the last 10 years and currently under immunosuppressive therapy Vaccination with two doses of Coronavac vaccine or BNT162b2 vaccines, followed by a booster dose (3d dose) of BNT162b2 vaccine administered in the previous 8-12 weeks. Exclusion Criteria: Previous SARS-CoV-2 infection Booster vaccine (3rd dose) administered less than 8 weeks or more than 12 weeks before enrolment Intravenous immunoglobulin therapy 60 days before enrolment Previous SARS-CoV-2 vaccine different from CoronaVac or BNT162b2

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Three doses of BNT162b2 vaccine<br>Solid organ transplant patients who received three doses of BNT162b2 | Biological: Three doses of SARS-CoV-2 BNT162b2 vaccine (observational)<br>* Two doses of SARS-CoV-2 BNT162b2 mRNA vaccine, followed by a booster (3rd) dose of SARS-CoV-2 BNT162b2 mRNA vaccine.<br>|
| Two doses of Coronavac and one of BNT162b2 vaccine<br>Solid organ transplant patients who received two doses of CoronaVac and one dose of BNT162b2 | Biological: Two doses of CoronaVac and one dose of BNT162b2 SARS-CoV-2 vaccine (observational)<br>* Two doses of CoronaVac SARS-CoV-2 inactivated vaccine, followed by a booster (3rd) dose of BNT162b2 mRNA vaccine.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| IgG seropositivity 8-12 weeks after third dose BNT162b2 (booster) vaccine. |  | 8-12 weeks after booster vaccine | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of positive neutralizing antibodies 8 to 12 weeks after third dose BNT162b2 (booster) vaccine. |  | 8-12 weeks after booster vaccine | 
| Neutralizing geometric mean titers 8 to 12 weeks after third dose of BNT162b2 (booster) vaccine. |  | 8-12 weeks after booster vaccine |