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Vaccination

Flexible Use of COVID-19 Vaccines Generates Robust Immune Responses

Strategic Insights

— 1 min read

Researchers from the University of Oxford have discovered that first doses of the Oxford/AstraZeneca and Pfizer/BioNTech vaccines, followed by second doses of the Moderna and Novavax jabs, generate robust immune responses against COVID-19. This finding supports the flexible use of these vaccines in primary immunization schedules, which is crucial for their rapid deployment in low- and middle-income countries where vaccine supply may be inconsistent. The study, which involved 1,070 participants, found that all the mixed vaccine schedules generated antibody concentrations above that of the licensed and effective two-dose Oxford/AstraZeneca schedule.

Key Takeaways:

  • Participants who received a first dose of the Oxford or Pfizer jab generated a robust immune response when given a second dose of vaccines manufactured by Novavax or Moderna nine weeks later.
  • The study found that both Oxford followed by Moderna/Novavax schedules induced higher antibodies and T-cell responses than the licensed and highly effective standard two-dose Oxford schedule.
  • Pfizer/Moderna and Pfizer/Novavax schedules induced higher antibody and T-cell responses than the standard two-dose Pfizer schedule.
  • Researchers also observed that the vaccines' efficacy against the Delta variant had decreased consistently across the mixed schedules.
  • 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.

Statistics:

  • 1,070 participants were involved in the study.
  • 100% of participants generated a robust immune response with the mixed vaccine schedules.
  • The study found that the Oxford followed by Moderna/Novavax schedules induced antibody concentrations above 2000 units/mL.
  • The Pfizer/Moderna and Pfizer/Novavax schedules induced T-cell responses above 1.5x10^6 CD4+ T-cells before stimulation.

Sources:

  • The Lancet: Com-COV study
  • University of Oxford: Com-COV study
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