Superior immunogenicity of mRNA over adenoviral vectored COVID-19 vaccines reflects B cell dynamics independent of anti-vector immunity: Implications for future pandemic vaccines

Vaccine. 2023 Nov 22;41(48):7192-7200. doi: 10.1016/j.vaccine.2023.10.034. Epub 2023 Oct 28.

Abstract

Both vector and mRNA vaccines were an important part of the response to the COVID-19 pandemic and may be required in future outbreaks and pandemics. The aim of this study was to validate whether immunogenicity differs for adenoviral vectored (AdV) versus mRNA vaccines against SARS-CoV-2, and to investigate how anti-vector immunity and B cell dynamics modulate immunogenicity. We enrolled SARS-CoV-2 infection-naïve health care workers who had received two doses of either AdV AZD1222 (n = 184) or mRNA BNT162b2 vaccine (n = 274) between April and October 2021. Blood was collected at least once, 10-48 days after vaccine dose 2 for antibody and B cell analyses. Median ages were 42 and 39 years, for AdV and mRNA vaccinees, respectively. Surrogate virus neutralization test (sVNT) and spike binding antibody titres were a median of 4.2 and 2.2 times lower, respectively, for AdV compared to mRNA vaccinees (p < 0.001). Median percentages of memory B cells that recognized fluorescent-tagged spike and RBD were 2.9 and 8.3 times lower, respectively for AdV compared to mRNA vaccinees. Titres of IgG reactive with human adenovirus type 5 hexon protein rose a median of 2.2-fold after AdV vaccination but were not correlated with anti-spike antibody titres. Together the results show that mRNA induced substantially more sVNT antibody than AdV vaccine, which reflected greater B cell expansion and targeting of the RBD rather than an attenuating effect of anti-vector antibodies. ClinicalTrials.gov Identifier: NCT05110911.

Keywords: Antibody; B cells; COVID-19; SARS-CoV-2; Vaccine; Vector; mRNA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies
  • Antibodies, Viral
  • BNT162 Vaccine
  • COVID-19 Vaccines
  • COVID-19* / prevention & control
  • ChAdOx1 nCoV-19
  • Humans
  • Pandemics / prevention & control
  • SARS-CoV-2
  • Viral Vaccines*

Substances

  • COVID-19 Vaccines
  • BNT162 Vaccine
  • ChAdOx1 nCoV-19
  • Viral Vaccines
  • Antibodies
  • Antibodies, Viral

Associated data

  • ClinicalTrials.gov/NCT05110911