P-2057. Immunogenicity of COVID-19 Booster Vaccines in Mexico and Mongolia
Authors: Regalado-Pineda Justino , Guerra-de-Blas Paola del Carmen , Grieco Megan C , Batkhuu Munguntsetseg , Becerril-Vargas Eduardo , Dashdorj Naranjargal , Dennis Dehkontee , Highbarger Helene , Hunsberger Sally , Jargalsaikhan Ganbolor , Mapleh Selwrenee , McCormack Ashley , Nyuangar Garmai , Ramírez-Hinojosa Juan Pablo , Ridzon Renee , Roldán-Aragón Yuri Alfonso , Ruiz-Palacios Guillermo Miguel , Sepúlveda-Delgado Jesús , Sereti Irini , Shaw-Saliba Katy , Smolskis Mary 
Published: January 2025

Abstract

Background
InVITE (NCT# 05096091) is a 7-country observational study assessing immune responses to COVID-19 vaccines offered from national vaccination programs. This analysis focuses on the response 2 months after receipt of a booster vaccine (third dose) among participants from Mexico and Mongolia. Vaccines assessed were mRNA (Comirnaty, Pfizer (BioNTech), non-replicating viral vector (Vaxzevria, Oxford/AstraZeneca; Sputnik-V, Gam-COVID-Vac), or inactivated virus vaccines (CoronaVac, SinoVac and Covilo, Sinopharm).

Methods
Blood samples were taken at baseline (Visit 1) and 2 months after receipt of booster (Visit 2). Information on primary vaccine regimens (receipt of first 2 COVID-19 vaccine doses) was collected. Quanterix SARS-CoV-2 Spike IgG assay measured anti-Spike (S) antibody levels. BioRad Platelia SARS-CoV-2 assessed anti-Nucleocapsid pan Ig (anti-N) antibody levels. Multivariate regression models were used to compare booster vaccines and regimens (primary+booster) based on log10 anti-S levels. CoronaVac and Covilo were excluded from some analyses due to small numbers (≤10 participants).
Violin plot with estimates and 95% confidence intervals (CI) of anti-S levels at Visit 1 and Visit 2. Groups with &gt;10 participants were included.

Results
We report on 698 participants with Visit 1 and Visit 2 anti-S levels measured. 59.5% were women, 46.3% were 40-59 and 24.4% were ≥60 years old. 33.7% reported hypertension/diabetes and 22.2% had body mass index &gt;30. 65.6% and 70.8% were positive for anti-N antibodies, at Visit 1 and 2, respectively. Anti-S levels at Visits 1 and 2 are shown in Figure 1. After adjusting for country, the booster with Comirnaty produced higher anti-S levels compared to Vaxzevria and Sputnik V, and Sputnik V produced relatively higher levels than Vaxzevria (Figure 2). When comparing combinations of primary and booster vaccines, Comirnaty + Comirnaty had the highest anti-S levels (Figure 3).
Difference between log10 anti-S levels at Visits 1 and 2 with 95% CI for comparison of booster vaccines, adjusted for country.

Conclusion
Immune response to booster COVID-19 immunization differed by vaccine with the highest response seen when Comirnaty was included in a regimen. These data, including vaccines and geographic locations rarely reported in other studies, enrich understanding of immunogenicity to different combinations of vaccines used as primary and booster doses.
Figure 3
Difference between vaccine combinations (primary vaccine + booster vaccine) log 10 anti-S levels with 95% CI to compare combinations. Rows without a line indicate 'no data' for those combinations.

Disclosures
Juan Pablo Ramírez-Hinojosa, MD, Abott: Honoraria|Jansen: Honoraria|Silanes: Honoraria Irini Sereti, M.D., NeoImmunotech: Collaboration