Heterologous Prime-Boost Regimen of COVID-19 Vaccines Increases Neutralizing Antibodies Against SARS-CoV-2

Strategic Insights -

Researchers in Germany have found evidence that a booster shot of a messenger RNA (mRNA)-based COVID-19 vaccine following prime immunization with AstraZeneca's adenoviral vector-based vaccine is sufficient to achieve high levels of neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The heterologous prime-boost regimen using different COVID-19 vaccines may even increase the efficacy of vaccination, providing an alternative approach to immunization in settings where vaccines are in short supply.

Key Takeaways:

  • A heterologous prime-boost regimen using AstraZeneca's adenoviral vector-based vaccine as a prime dose and Pfizer-BioNTech's mRNA-based vaccine as a booster shot induced significantly higher neutralizing antibody titers against SARS-CoV-2 compared to homologous regimens.
  • The levels of neutralizing antibodies achieved in this group were compared with those among cohorts of healthcare workers or volunteers who were immunized using a homologous Pfizer-BioNTech or AstraZeneca regimen.
  • The study included 229 individuals who received a heterologous vaccination using AstraZeneca's adenoviral vector-based vaccine as the prime immunization and Pfizer-BioNTech's mRNA-based vaccine as the booster shot.
  • The team observed a striking increase in the levels of neutralizing antibodies against SARS-CoV-2 among the vaccinees who received a booster dose of Pfizer-BioNTech's vaccine between 9 and 12 weeks after receiving a prime dose of AstraZeneca's vaccine.
  • The heterologous prime-booster regimen may increase vaccine efficacy and provide an alternative approach to immunization in settings where vaccines are in short supply.

Statistics:

  • The heterologous prime-boost regimen involved 229 individuals who received a booster dose of Pfizer-BioNTech's vaccine.
  • The study compared the levels of neutralizing antibodies among 480 individuals at two different time points.
  • The heterologous prime-booster regimen induced significantly higher neutralizing antibody titers than the homologous AstraZeneca or Pfizer-BioNTech regimens.

Sources:

  • Protzer, et al. (2021). "Heterologous prime-boost vaccination with a mRNA-based COVID-19 vaccine following adenoviral vector-based initial prime immunization." medRxiv*. 10.1101/2021.02.22.21252096