Phase 2 Trial of Oxford COVID-19 Vaccine in Healthy Older Adults Finds It Is Safe and Provokes Immune Response; Similar Results Seen in Younger Adults; Phase 3 Trials Ongoing

The UK's vaccine against SARS-CoV-2 shows similar safety and immunogenicity results in healthy older adults (aged 56 years and over) to those seen in adults aged 18-55 years. The promising early-stage results were published online on November 18, 2020 in The Lancet ( The open-access article is titled “Safety and Immunogenicity of ChAdOx1 nCoV-19 Vaccine Administered in a Prime-Boost Regimen in Young and Old Adults (COV002): a Single-Blind, Randomised, Controlled, Phase 2/3 Trial.” The phase 2 trial finds that the vaccine causes few side effects, and induces immune responses in both parts of the immune system in all age groups and at low and standard dose--provoking a T-cell response within 14 days of the first dose of vaccination (i.e., a cellular immune response, it could find and attack cells infected with the virus), and an antibody response within 28 days of the booster dose of vaccination (i.e., humoral immune response, it could find and attack the virus when it was circulating in the blood or lymphatic system). Phase 3 trials are ongoing to confirm these results--as well as how effective the vaccine is in protecting against infection with SARS-CoV-2 - in a broader range of people, including older adults with underlying health conditions. Study lead author Professor Andrew Pollard, University of Oxford, UK, says: "Immune responses from vaccines are often lessened in older adults because the immune system gradually deteriorates with age, which also leaves older adults more susceptible to infections. As a result, it is crucial that COVID-19 vaccines are tested in this group who are also a priority group for immunization." Co-author Dr. Maheshi Ramasamy, University of Oxford, UK, adds:
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