Interim results from the ongoing Phase I/II COV001 trial, led by Oxford University, showed AZD 1222 vaccine, from AstraZeneca, was tolerated and generated robust immune responses against the SARS-CoV-2 virus in all evaluated participants. COV001 is a blinded, multi-centre, randomised controlled Phase I/II trial with 1,077 healthy adult participants, aged 18-55 years. It assessed a single dose of AZD 1222 against a comparator meningococcal conjugate vaccine, MenACWY. Ten participants also received two doses of AZD 1222 one month apart.
The results published in The Lancet confirmed a single dose of AZD1222 resulted in a four-fold increase in antibodies to the SARS-CoV-2 virus spike protein in 95% of participants one month after injection. In all participants, a T-cell response was induced, peaking by day 14, and maintained two months after injection. Neutralising activity against SARS-CoV-2 (as assessed by the MNA80 assay) was seen in 91% of participants one month after vaccination and in 100% of participants who received a second dose. The levels of neutralising antibodies seen in participants receiving either one or two doses were in a similar range to those seen in convalescent COVID-19 patients. Strong correlations were observed across neutralisation assays.
The early safety responses confirmed that transient local and systemic reactions were common in the AZD 1222 group and were comparable to previous trials and other adenoviral vector vaccines. They included temporary injection site pain and tenderness, mild-to-moderate headache, fatigue, chills, feverishness, malaise and muscle ache. No serious adverse events were reported with AZD 1222, and reactions were lessened with the use of prophylactic paracetamol, a pain killer, and occurred less frequently after a second dose.
See: “Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase I/II, single-blind, randomised controlled trial” Pedro M Folegatti et al. The Lancet Published:July 20, 2020 DOI:https://doi.org/10.1016/S0140-6736(20)31604-4