What vaccines are available in other countries or on the horizon for the U.S.?

AstraZeneca-Oxford Vaccine

  • Background
    • This two-dose vaccine is a weakened adenovirus-based vaccine. Researchers genetically altered a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees so it carried a gene for the COVID-19 spike protein; this will train a person’s immune system to recognize the real coronavirus.
    • This vaccine has been approved for emergency use in the United Kingdom, the European Union, and Canada.
  • Efficacy
    • One dosing regimen showed vaccine efficacy of 90% when AZD1222 was given as a half dose, followed by a full dose at least one month apart, and another dosing regimen (n=8,895) showed 62% efficacy when given as two full doses at least one month apart. The combined analysis from both dosing regimens (n=11,636) resulted in an average efficacy of 70%
    • No hospitalizations or severe cases of the disease were reported in participants receiving the vaccine.
    • This vaccine was found to have similar efficacy for the U.K. variant than the original strain; however, in South Africa, it was found to have low efficacy for mild to moderate COVID-19, causing concerns that it is not effective against that variant; because the study was small and had young and healthy participants, it could not assess for efficacy against moderate to severe COVID-19
    • New data (currently waiting for peer review) shows that that the effect of dosing interval on efficacy is pronounced, with vaccine efficacy rising from 54.9% with an interval of less than six weeks to 82.4% when spaced 12 or more weeks apart
    • New data also shows that a single standard dose of the vaccine is 76% effective at protecting from primary symptomatic COVID-19 for the first 90 days post vaccination, once the immune system has built this protection 22 days after the vaccination.

Novavax vaccine

  • Background
    • This two-dose vaccine is made from a stabilized form of the coronavirus spike protein using the company’s recombinant protein nanoparticle technology. The purified protein antigens in the vaccine cannot replicate and cannot cause COVID-19. The vaccine also contains a proprietary adjuvant, MatrixMTM. Adjuvants are additives that enhance desired immune system responses to vaccine.
    • Clinical trials in the U.K and South Africa have reported data; The US and Mexico PREVENT-19 Phase 3 clinical trial has randomized over 16,000 participants toward our enrollment goal of 30,000.
  • Efficacy
    • 89.3% efficacy in Phase 3 UK trial with over 50% of cases attributable to the now-predominant UK variant and the remainder attributable to COVID-19 virus
    • 49.4% efficacy in total study population (60% efficacy in 94% of the study population that was HIV negative) was demonstrated in Phase 2b South Africa trial with over 90% of sequenced cases attributable to prevalent South Africa escape variant.


Updated: March 1, 2021