AZD1222 FDA Approval Status
AZD1222 (formerly ChAdOx1 nCoV-19) is an investigational vaccine against SARS-CoV-2 in development for the prevention of COVID-19.
- AZD1222 works by using a viral vector (ChAdOx1 - chimpanzee adenovirus Oxford 1) based on a weakened version of a common cold (adenovirus) virus that contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the virus if it later infects the body, protecting it against COVID-19.
- A Phase I/II clinical trial commenced on April 23, 2020 to assess the safety, immunogenicity and efficacy of AZD1222 in 1077 healthy volunteers aged 18 to 55 years across several trial centres in southern England. Interim results were published in The Lancet on July 20, 2020.
- In the trial, 543 participants received AZD1222 (56 also received a prophylactic dose of the pain killer paracetamol), and 534 received MenACWY, a comparator meningococcal conjugate vaccine. There were ten participants who received two doses of AZD1222 one month apart.
- The results 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.
- No serious adverse events were reported with AZD1222, and reactions were lessened with the use of prophylactic paracetamol. Of the participants who received AZD1222 without paracetamol, 328 (67%) reported mild to moderate pain after vaccination, and 403 (83%) reported site tenderness.
- Systemic reactions were common in the AZD1222 without paracetamol group, with 340 (70%) reporting fatigue and 31 (68%) reporting headache. Other reactions reported in this group include muscle aches (60%), malaise (61%), chills (56%), and feeling feverish (51%). Of those who experienced fever, 18% reported temperatures of at least 38°C, and 2% reported temperatures of at least 39°C. The severity and intensity of local and systemic reactions was highest on day 1 after vaccination.
- Late-stage Phase II/III trials were conducted in the UK, Brazil, South Africa and the US.
- Vaccine Maker Halts Trial Following Unexplained Illness in Volunteer September 9, 2020
AstraZeneca COVID Vaccine Trial Restarts September 14, 2020
Details Emerge on Unexplained Illness in AstraZeneca COVID Vaccine Trial September 18, 2020
- Investigating a Vaccine Against COVID-19 (ClinicalTrials.gov)
- A Study of a Candidate COVID-19 Vaccine (COV001) (ClinicalTrials.gov)
Development Timeline for AZD1222
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