COVID-19: the "Oxford vaccine" shows phase 1/2 promise

  • Folegatti PM & et al
  • Lancet
  • 21 Jul 2020

  • curated by Liz Scherer
  • Clinical Essentials
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Takeaway

  • The "Oxford vaccine" yielded rapid induction of both anti-COVID-19 humoral and cellular immune responses and was well-tolerated in phase 1/2.

Why this matters

Key results

  • 1077 participants:
    • 543 in the "Oxford" group.
    • 534 controls receiving meningococcal group A, C, W-135, Y conjugate vaccine.
    • 10 enrolled in prime-boost group administered at day 28.
  • Median age, 35 (interquartile range [IQR] 28-44) years.
  • 49.8% female, 50.2% male.
  • 56 in Oxford group and 57 in control group received prophylactic paracetamol/acetaminophen. 
  • With Oxford vaccine, SARS-CoV-2 spike protein antibodies:
    • Peaked by day 28 (median 157 ELISA units [EU], IQR 96-317; n=127).
    • Remained elevated to day 56 (119 EU, 70-203, n=43) with 1 dose. 
    • Increased to median 639 EU (360-792) at day 56 with prime booster.
  • Depending on assay, 91%-100% achieved neutralizing titers by day 28.
  • 100% achieved postbooster titers.
  • Titers (PseudoNA assay, Marburg VN) correlated positively with ELISA (both P<.001>
  • Local and systemic adverse effects were common with the test vaccine (mostly muscle ache, malaise, chills, fever).

Study design

  • Phase 1/2, single-blind, randomized controlled safety and immunogenicity trial of the ChAdOx1 nCoV-19 ("Oxford") vaccine.
  • Funding: UK Research and Innovation; others.

Limitations

  • Short follow-up.
  • Small booster sample.
  • Single-blind.
  • Limited generalizability.