AZD1222
 AZD1222    | |
|---|---|
 | |
| Interest of | Sarah Gilbert |
AZD1222 (also known as ChAdOx1 nCoV-19) is a COVID-19 vaccine developed by Oxford University and AstraZeneca collaborating with the Italian biotech firm Irbm Science Park[1] given by intramuscular injection, using as a vector the modified chimpanzee adenovirus (ChAdOx1).[2]
The research is being done by the Oxford University's Jenner Institute and Oxford Vaccine Group. The team is led by Sarah Gilbert, Adrian Hill, Andrew Pollard, Teresa Lambe, Sandy Douglas and Catherine Green.[3]
On 8 December 2020, The Lancet published an article entitled "Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK". There were 11,636 participants (7,548 in the UK, 4,088 in Brazil) included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% and in participants who received a low dose followed by a standard dose, efficacy was 90·0%. Overall AZD1222 vaccine efficacy across both groups was 70·4%.[4]
Contents
Approved for use
On 30 December 2020, AZD1222 was approved for use in the COVID-19 vaccination programme in the United Kingdom.[5][6]
The Government has today accepted the recommendation from the Medicines and Healthcare Products Regulatory Agency (MHRA) to authorise Oxford University/AstraZeneca’s COVID-19 vaccine for use. This follows rigorous clinical trials and a thorough analysis of the data by experts at the MHRA, which has concluded that the vaccine has met its strict standards of safety, quality and effectiveness.[7]
Adenovirus vector
The AZD1222 vaccine is a replication-deficient simian adenovirus vector, containing the full‐length codon‐optimised coding sequence of SARS-CoV-2 spike protein along with a tissue plasminogen activator (tPA) leader sequence.[8]
The researchers used the SARS-CoV-2 genome that had been sequenced in Wuhan. The modified monkey adenovirus cannot replicate, so does not cause further infection, and instead acts as a vector to transfer the SARS-CoV-2 spike protein.[9]
The spike S1 protein is an external protein that enables the SARS-type coronavirus to enter cells through the enzymatic domain of ACE2. After vaccination, this spike protein is produced, promoting the immune system to attack the coronavirus if it later infects the body.[10]
Combining with Sputnik V
On 11 December 2020, AstraZeneca announced a clinical trial programme to assess safety and immunogenicity of a combination of AZD1222 and Sputnik V, developed by Russian Gamaleya Research Institute. Dr Zoltán Kis, Research Associate at the Future Vaccine Manufacturing Hub, Imperial College (London), said:
“Both the AstraZeneca/Oxford vaccine candidate and the Sputnik V vaccine are adenovirus vectored vaccines and both deliver genetic instructions for the cells of the body to produce the Spike protein of SARS-CoV-2. The AstraZeneca/Oxford vaccine candidate is based on a chimpanzee adenovirus and the Sputnik V vaccine is based on a human adenovirus, thus the vectors (or carriers) of these two vaccines are slightly different.
“The immune system of the human body can generate an immune response against the adenoviral vector itself, thus if a second dose of the same adenovirus vectored vaccine is delivered, the immune system could destroy the vector, before the payload of the vaccine is delivered, therefore reducing the efficacy of the second vaccine dose. On the other hand, if the vector of the second (booster) dose of the vaccine is different from the vector of the first (prime) dose, the immune system will be less likely to destroy the vector of the vaccine, thus the efficacy of the heterologous boosting vaccination could be increased, compared to the situation where both the prime and boost doses were of the same vector type. Therefore, the reason why heterologous boosting could increase vaccine efficacy, is that the (partial) destruction of the second vaccine dose by the immune system can be avoided and because both vaccines contain instructions for producing the same antigen.
“Furthermore, having the possibility of combining these two vaccine types would allow for greater flexibility in the vaccination programs. This could lead to greater accessibility to vaccines, thus increasing the rate and scale of Covid-19 vaccination coverage.
“For these reasons, the news regarding clinical trials of this heterologous boosting Covid-19 vaccination is a promising one.”[11]
AZD1222 victims on Wikispooks
| Title | Description |
|---|---|
| Michelle Barlow | British woman who died from the Oxford–AstraZeneca COVID-19/Vaccine. |
| Lisa Shaw | British radio presenter who tragically died after having the Oxford–AstraZeneca COVID-19/Vaccine. |
| Alpa Tailor | British woman who died from the Oxford–AstraZeneca COVID-19/Vaccine. |
Related Quotations
| Page | Quote | Author | Date |
|---|---|---|---|
| Byram Bridle | “But this is because these COVID-19 vaccines have reached the public rollout phase by, and I’ll say it in quotes, “cutting corners”. And by cutting corners, I’m not implying that people were skipping key steps, although honestly, there could be some potential questions around that.” | Byram Bridle | 24 February 2021 |
| Byram Bridle | “None of us were expecting, I don’t think, that the vaccines would be rolled out very early on in the phase three clinical trials. So the phase three trials are not done. So in essence, what this means is the public rollout right now is an extension of the phase three clinical trial. So those being vaccinated now are, whether they realize it or not, part of the phase three experiment.” | Byram Bridle | 24 February 2021 |
References
- ↑ "The Jenner Institute signs an agreement with Advent to develop a novel coronavirus vaccine"
- ↑ "The world's hopes for a coronavirus vaccine may run in these health care workers' veins"
- ↑ "Oxford team to begin novel coronavirus vaccine research"
- ↑ "Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK"
- ↑ "Covid-19: Oxford-AstraZeneca coronavirus vaccine approved for use in UK"
- ↑ "Is good news for India on the vaccine front here?"
- ↑ "Oxford University/AstraZeneca vaccine authorised by UK medicines regulator"
- ↑ Reviews in Medical Virology: "Severe acute respiratory syndrome-coronavirus-2 spike (S) protein based vaccine candidates: State of the art and future prospects" by Arashkia A, Jalilvand S, Mohajel N, Afchangi A, Azadmanesh K, Salehi-Vaziri M, Fazlalipour M, Pouriayevali MH, Jalali T, Mousavi Nasab SD, Roohvand F, Shoja
- ↑ "Exeter Fellow Dr Catherine Green leads the production of a potential COVID-19 vaccine in Oxford"
- ↑ Cell Research: "SARS coronavirus entry into host cells through a novel clathrin- and caveolae-independent endocytic pathway" by Wang H, Yang P, Liu K, Guo F, Zhang Y, Zhang G, Jiang C
- ↑ "Expert reaction to AstraZeneca announcing clinical trial programme to assess combination of the Oxford AstraZeneca vaccine and the Sputnik V vaccine"
This page imported content from Wikipedia on 31 December 2020.Wikipedia is not affiliated with Wikispooks. Original page source here
