Effect of heterologous vaccination regimen with Ad5-nCoV CanSinoBio and BNT162b2 Pfizer in SARS-CoV-2 IgG antibodies titers

Introduction

The efficacy with one dose Ad5-nCoV has been concerned. As a result, some patients have self-reported getting a boost with BNT. Therefore, this study aimed to compare SARS-CoV-2 spike 1-2 IgG antibodies in plasma samples between two groups: one group immunized with Ad5-nCoV and another with a heterologous vaccination regimen with Ad5-nCoV and BNT.

Methods

Prospective observational study included a subgroup analysis of patients who received the Ad5-nCoV immunization during the first trimester of 2021 in a Northern city of Mexico; and agreed to a follow-up for an entire year through SARS-CoV-2 specific IgG antibodies measurement samples. During the three months follow-up, some patients self-reported receiving a BNT boost. We report IgG levels from basal, 21-28 days after Ad5-nCoV dose, three months, and an additional 21-28 days after BNT boost.

Results

Seventeen patients 40 (16) years old, 52.9% men, were analyzed. We created four groups: (G1) patients vaccinated with Ad5-nCoV with no history of SARS-COV-2 (n=4), (G2) patients vaccinated with Ad5-nCoV and the first shot of BNT with no history of SARS-COV-2 (n=6), (G3) patients vaccinated with Ad5-nCoV with history of SARS-COV-2 (n=5), and (G4) patients vaccinated with Ad5-nCoV and the first shot of BNT with history of SARS-COV-2 (n=2).

The group immunized with a heterologous vaccine scheme reported higher antibodies after 21-28 days of follow-up after BNT boost. Median (IQR): G1 46.7 (-), G2 1077.5 (1901), G3 1158.5 (2673.5), and G4 2090 (-) (p<0.05). Headache was the most frequent adverse reaction when patients received Ad5-nCoV (n = 10, 83%), and pain at the injection site was the most frequent adverse reaction with BNT boost (n = 5, 83.3%).

Conclusion

Patients receiving a BNT boost after Ad5-nCoV had higher SARS-CoV-2 spike 1-2 IgG antibodies titers with no severe adverse reaction.

Author Approval

all authors read an approved the final version of the manuscript

Competing Interests

The authors have declared no competing interest

Funding

The research was supported by private funding provided by the hospital. No external funding was used.

Ethics statement

Ethics committee/local Institutional Review Board from the school of Medicine from Universidad de Monterrey gave ethical approval: Ref.:26022021-CN-1e-CI