Heterologous ChAdOx1 nCoV-19/BNT162b2 Prime-Boost Vaccination Induces Strong Humoral Responses among Health Care Workers

Louise Benning; Maximilian Töllner; Asa Hidmark; Matthias Schaier; Christian Nusshag; Florian Kälble; Paula Reichel; Mirabel Buylaert; Julia Grenz; Gerald Ponath; Katrin Klein; Martin Zeier; Caner Süsal; Paul Schnitzler; Christian Morath; Claudius Speer

doi:10.3390/vaccines9080857

Heterologous ChAdOx1 nCoV-19/BNT162b2 Prime-Boost Vaccination Induces Strong Humoral Responses among Health Care Workers

Vaccines (Basel). 2021 Aug 4;9(8):857. doi: 10.3390/vaccines9080857.

Authors

Louise Benning¹, Maximilian Töllner¹, Asa Hidmark¹, Matthias Schaier¹, Christian Nusshag¹, Florian Kälble¹, Paula Reichel¹, Mirabel Buylaert¹, Julia Grenz¹, Gerald Ponath¹, Katrin Klein¹, Martin Zeier¹, Caner Süsal², Paul Schnitzler³, Christian Morath¹, Claudius Speer^{1

4}

Affiliations

¹ Department of Nephrology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
² Institute of Immunology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
³ Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany.
⁴ Molecular Medicine Partnership Unit Heidelberg, EMBL, 69117 Heidelberg, Germany.

Abstract

Despite limited data on safety and immunogenicity, heterologous prime-boost vaccination is currently recommended for individuals with ChAdOx1 nCoV-19 prime immunization in certain age groups. In this prospective, single-center study we included 166 health care workers from Heidelberg University Hospital who received either heterologous ChAdOx1 nCoV-19/BNT162b2, homologous BNT162b2 or homologous ChAdOx1 nCoV-19 vaccination between December 2020 and May 2021. We measured anti-S1 IgG, SARS-CoV-2 specific neutralizing antibodies, and antibodies against different SARS-CoV-2 fragments 0-3 days before and 19-21 days after boost vaccination. Before boost, 55/70 (79%) ChAdOx1 nCoV-19-primed compared with 44/45 (98%) BNT162b2-primed individuals showed positive anti-S1 IgG with a median (IQR) anti-S1 IgG index of 1.95 (1.05-2.99) compared to 9.38 (6.26-17.12). SARS-CoV-2 neutralizing antibodies exceeded the threshold in 24/70 (34%) of ChAdOx1 nCoV-19-primed and 43/45 (96%) of BNT162b2-primed individuals. After boosting dose, median (IQR) anti-S1 IgG index in heterologous ChAdOx1 nCoV-19/BNT162b2 vaccinees was 116.2 (61.84-170), compared to 13.09 (7.03-29.02) in homologous ChAdOx1 nCoV-19 and 145.5 (100-291.1) in homologous BNT162b2 vaccinees. All boosted vaccinees exceeded the threshold for neutralization, irrespective of their vaccination scheme. Vaccination was well-tolerated overall. We show that heterologous ChAdOx1 nCoV-19/BNT162b2 vaccination is safe and induces a strong and broad humoral response in healthy individuals.

Keywords: BNT162b2; COVID-19; COVID-19 vaccination; ChAdOx1 nCoV-19; SARS-CoV-2; adenovirus-vectored vaccine; heterologous vaccination; humoral response; mRNA vaccine.