A safe and effective vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will be an important tool in controlling the global COVID-19 pandemic. Although there are no licensed vaccines against COVID-19, 48 potential vaccine candidates based on a variety of platforms including lipid nanoparticle mRNA, DNA, adjuvanted protein, inactivated virus particles, and non-replicating viral vectors are in clinical trials (of which 11 candidates are in phase 3 trials) and a further 164 candidates are in preclinical testing.
A team of scientists at Oxford University’s and AstraZeneca has taken the next step towards the discovery of a safe, effective and accessible vaccine against coronavirus. Oxford vaccine is cheaper to produce, and unlike the other vaccines that require a demanding cold chain storage, can be kept at standard refrigerator temperatures of between 2C and 8C.
Following the trial reaching the target for interim analysis, the independent Data and Safety Monitoring Board (DSMB) recommended that the team at Oxford conduct its first analysis on all the cases with data locked on 4 November 2020.
The vaccine demonstrated average efficacy of 70.4%, according to results of clinical trials. The interim analysis of phase 2/3 trials in the UK and Brazil found efficacy of 62% following two full doses given at least one month apart.
However, vaccine efficacy was 90% when ChAdOx1 nCoV-19, also known as AZD1222, was given to a subset of participants as a half dose, followed by a full dose at least one month later.
Additional cases are expected to accrue by the time of the final analysis and future analyses will determine the duration of protection. No serious safety events related to the vaccine have been identified.
The results of the Phase II/III trial published in the scientific journal, The Lancet.
Below are the side effects observed as per article published from safety and immunogenicity results of a phase 2 component of a phase 2/3 multicentre study using ChAdOx1 nCoV-19 at two different doses, in adults including those aged 56–69 years and 70 years and older, and in a one-dose or two-dose regimen which is being run at 20 centres in the UK.
- Injection-site pain and tenderness were the most common solicited local adverse reactions and occurred most frequently in the first 48 h after vaccination.
- Fatigue, headache, feverishness, and myalgia were the most commonly solicited systemic adverse reactions
- 13 serious adverse events have occurred (across all age and vaccine groups), none of which are considered related to either study vaccine as assessed by the investigators. (Events are appendicitis, Allergic reaction wasp sting, Pneumonia, Unstable angina, Sigmoid volvulus, Limb ischaemia, Acute diverticulitis, Vertebral fracture, Ovarian cyst, Hernia, Prostate cancer, Polymyalgia rheumatica, Bilateral lower limb oedema)
The phase 3 clinical trials are ongoing and they are enrolling over 24,000 participants from diverse racial and geographical groups in the UK, Brazil and South Africa, will now continue to final analysis. Further trials are being conducted in the United States, Kenya, Japan and India and the trial team expect to have under 60,000 participants by the end of the year. These trials will provide regulators with further information about the efficacy and safety of the Oxford candidate vaccine, including its ability to both protect against and stop the transmission of COVID-19.
Reference: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32466-1/fulltext#sec1
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