"Mix and Match" Vaccine Schedules Generate Robust Immune Responses Against Covid-19

Strategic Insights -

Researchers from the University of Oxford have conducted a study on the effectiveness of different "mix and match" vaccine schedules against Covid-19. The study, published in The Lancet, found that various combinations of vaccines, such as the Oxford/AstraZeneca and Pfizer/BioNTech vaccines followed by the Moderna or Novavax jabs, generated robust immune responses against the virus. This flexible use of vaccines is crucial for rapid deployment, particularly in low- and middle-income countries where vaccine supply may be inconsistent.

Key Takeaways:

  • The study found that mixing vaccines, such as Oxford/AstraZeneca followed by Moderna/Novavax, induced higher antibodies and T-cell responses than the standard two-dose Oxford schedule.
  • The combination of Pfizer/BioNTech followed by Moderna induced higher antibody and T-cell responses than the standard two-dose Pfizer schedule.
  • The combination of Pfizer/BioNTech followed by Novavax induced higher antibodies than the two-dose Oxford schedule.
  • A significantly higher number of short-lived vaccine reactions were reported in volunteers who received a second dose of Moderna compared to those who received two doses of the Oxford or Pfizer jabs.
  • The study also found that all mixed schedules generated antibody concentrations above that of the licensed and effective two-dose Oxford/AstraZeneca schedule.
  • When it comes to cellular immunity, having a first dose of the Oxford/AstraZeneca vaccine followed by any of the other study vaccines generates a particularly robust response.

Statistics:

  • 1,070 participants were involved in the study.
  • 540 million doses of seven promising vaccines, including the four so far approved for use, have been ordered by the UK.
  • 114 million more doses of the Pfizer and Moderna vaccines have been signed to be delivered in 2022 and 2023, respectively.
  • 92% of the UK's population has received both doses of a Covid-19 vaccine.
  • The UK has delivered over 80 million Covid-19 vaccines to date.

Sources:

  • The Lancet
  • University of Oxford
  • BBC News