PLoS Pathogens (Nov 2023)

Immunogenicity and safety of heterologous boost immunization with PastoCovac Plus against COVID-19 in ChAdOx1-S or BBIBP-CorV primed individuals.

  • Sana Eybpoosh,
  • Alireza Biglari,
  • Rahim Sorouri,
  • Fatemeh Ashrafian,
  • Mona Sadat Larijani,
  • Vicente Verez-Bencomo,
  • Maria Eugenia Toledo-Romani,
  • Carmen Valenzuela Silva,
  • Mostafa Salehi-Vaziri,
  • Sarah Dahmardeh,
  • Delaram Doroud,
  • Mohammad Banifazl,
  • Ehsan Mostafavi,
  • Anahita Bavand,
  • Amitis Ramezani

DOI
https://doi.org/10.1371/journal.ppat.1011744
Journal volume & issue
Vol. 19, no. 11
p. e1011744

Abstract

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BackgroundThis study aimed at evaluation and comparison of PastoCovac Plus protein-subunit vaccine in parallel with ChAdOx1-S (AstraZeneca) and BBIBP-CorV (Sinopharm) in primarily vaccinated volunteers with two doses of ChAdOx1-S or BBIBP-CorV.Materials and methods194 volunteers enrolled the study who were previously primed with 2 doses of ChAdOx1-S or BBIBP-CorV vaccines. They were divided into two heterologous regimens receiving a third dose of PastoCovac Plus, and two parallel homologous groups receiving the third dose of BBIBP-CorV or ChAdOx1-S. Serum samples were obtained just before and 4 weeks after booster dose. Anti-spike IgG and neutralizing antibodies were quantified and the conventional live-virus neutralization titer, (cVNT50) assay was done against Omicron BA.5 variant. Moreover, the adverse events data were recorded after receiving booster doses.ResultsChAdOx1-S/PastoCovac Plus group reached 73.0 units increase in anti-Spike IgG rise compared to the ChAdOx1-S/ ChAdOx1-S (P: 0.016). No significant difference was observed between the two groups regarding neutralizing antibody rise (P: 0.256), indicating equivalency of both booster types. Adjusting for baseline titers, the BBIBP-CorV/PastoCovac Plus group showed 135.2 units increase (PConclusionsPastoCovac Plus booster application in primed individuals with BBIBP-CorV or ChAdOx1-S successfully increased specific antibodies' levels without any serious adverse events. This vaccine could be administrated in the heterologous regimen to effectively boost humoral immune responses.