Oxford–AstraZeneca COVID-19 vaccine

The AZD1222 vaccine is a replication-deficient simian adenovirus vector, containing the full‐length codon‐optimized coding sequence of SARS-CoV-2 spike protein along with a tissue plasminogen activator (tPA) leader sequence.[18]

The researchers used the SARS-CoV-2 genome that had been sequenced in Wuhan. The modified chimpanzee adenovirus cannot replicate, so does not cause further infection, and instead acts as a vector to transfer the SARS-CoV-2 spike protein.[19]

The spike S1 protein is an external protein that enables the SARS-type coronavirus to enter cells through the enzymatic domain of ACE2.[20] After vaccination, this spike protein is produced, prompting the immune system to attack the coronavirus if it later infects the body.[21]

In February 2020, the Jenner Institute agreed a collaboration with the Italian company Advent Srl for the production of the first batch of a vaccine candidate for clinical trials.[22]

In March 2020,[23][24] after the Gates Foundation urged the University of Oxford to find a large company partner to get its COVID-19 vaccine to market, the university backed off from its earlier pledge to donate the rights to any drugmaker.[25] Also, the UK government encouraged the University of Oxford to work with AstraZeneca instead of Merck & Co., a US based company over fears of vaccine hoarding under the Trump administration.[26]

In June 2020, the US National Institute of Allergy and Infectious Diseases (NIAID) confirmed that the third phase of testing for potential vaccines developed by Oxford University and AstraZeneca would begin in July 2020.[27]

In July 2020, AstraZeneca partnered with IQVIA to speed up US clinical trials.[28]

On 31 August 2020, AstraZeneca announced that it had begun enrolling adults for a US-funded, 30,000-subject late-stage study.[29]

On 8 September 2020, AstraZeneca announced a global halt to the vaccine trial while a possible adverse reaction in a participant in the United Kingdom was investigated.[30][31][32] On 13 September, AstraZeneca and the University of Oxford resumed clinical trials in the United Kingdom after regulators concluded it was safe to do so.[33] AstraZeneca was criticized for vaccine safety after concerns from experts noting the company's refusal to provide details about serious neurological illnesses in two participants who received the experimental vaccine in Britain.[34] While the trial resumed in the UK, Brazil, South Africa, Japan[35] and India, it remained on pause in the US till 23 October 2020[36] while the Food and Drug Administration (FDA) investigated a patient illness that triggered the clinical hold, according to the United States Department of Health and Human Services (HHS) Secretary Alex Azar.[37]

On 15 October 2020, Dr João Pedro R. Feitosa, a 28-year-old doctor from Rio de Janeiro, Brazil, who received a placebo instead of the test vaccine in a clinical trial of AZD1222, died from COVID-19 complications.[38][39][40] The Brazilian health authority Anvisa announced that the trial would continue in Brazil.[41]

On 23 November 2020, Oxford University and AstraZeneca announced interim results from the vaccine's ongoing Phase III trials.[13][42] There was some criticism of the methods used in the report, which combined results of 62% and 90% from different groups of test subjects given different dosages to arrive at a 70% figure.[43][44][45] AstraZeneca said it would carry out a further multi-country trial using the lower dose which had led to a 90% claim.[46]

The full publication of these interim results, from four ongoing, blinded, randomised, controlled trials, on 8 December 2020, clarified these reports.[47] In the group who received the first dose of active vaccine more than 21 days earlier, there were no hospitalisations or severe disease, unlike those receiving the control vaccine. Serious adverse events were balanced across the active and control arms in the studies, i.e. the active vaccine wasn't considered to cause additional serious adverse events. A case of transverse myelitis was reported 14 days after booster vaccination as being possibly related to vaccination, with an independent neurological committee considering the most likely diagnosis to be of an idiopathic, short segment, spinal cord demyelination. The other two cases of transverse myelitis, one in vaccine group and the other in control group, were considered to be unrelated to vaccination.[47]

On 27 December 2020, the chief executive of AstraZeneca, Pascal Soriot said he believed researchers have found a "winning formula" in form of the Oxford–AstraZeneca COVID-19 vaccine, where two doses were used.[48]

On 4 January 2021, Brian Pinker, 82, became the first person to receive the Oxford–AstraZeneca COVID-19 vaccine outside of clinical trials.[17]

In February 2021 the Oxford-AstraZeneca have indicated they are working to adapt the vaccine to target new variants of the coronavirus,[49], with expectation of a modified vaccine being available "in a few months" which could also be used as a "booster jab".[50] A key area of concern due to has been the E484K mutation due to impact on body immune response and, possibly, current vaccine effectiveness.[51] The E48K mutation is present in the South African (B.1.351) and Brazilian (B.1.1.28) variants with a small number of cases of the mutation also detected in infections by the original SARS-C0V-2 virus and the UK/Kent (B.1.1.7) variant.[51]

In February 2021 a Phase II trial of the combination of AZD1222 and the Russian Sputnik V COVID-19 vaccine, both adenovirus vectored vaccines, started. The trial of 100 participants to determine the safety and immunogenicity is expected to complete in April 2021, with final reporting in September 2021.[52][53] The trial had been announced by AstraZeneca on 11 December 2020 to test if the combination would give improved protection levels.[54][55]

On 27 November 2020, the UK government asked the Medicines and Healthcare products Regulatory Agency to assess the AZD1222 vaccine for temporary supply,[56] and it was approved for use on 30 December 2020, as their second vaccine to enter the national rollout.[57]

The European Medicines Agency received an application for a Conditional Marketing Authorisation (CMA) for the vaccine on 12 January 2021. A press release stated that a recommendation on this could be issued by the agency by 29 January, with the European Commission then making a decision on the CMA within days.[3] The Hungarian regulator unilaterally approved the vaccine instead of waiting for EMA approval.[58]

On 29 January 2021, the European Medicines Agency (EMA) recommended granting a conditional marketing authorisation for AZD1222 in people from 18 years of age.[7]

The vaccine has also been approved by Argentina,[59] El Salvador,[60] India,[61][62] Mexico,[63] Bangladesh,[64] the Dominican Republic,[65] Pakistan,[66] the Philippines,[67] Nepal,[68] Brazil[69] and Sri Lanka[70] regulatory authorities for emergency usage in their respective countries.

On 7 February 2021, the vaccine roll out in South Africa was suspended. Researchers from the University of Witwatersrand said in a prior-to-peer analysis that the AstraZeneca vaccine provided minimal protection against mild or moderate disease infection among young people.[71][72] The BBC reported on 8 February 2021 that Katherine O'Brien, director of immunisation at the World Health Organization, indicated she felt it was "really plausible" the AstraZeneca vaccine could have a "meaningful impact" on the South African variant particularly in preventing serious illness and death.[73] The same report also indicated the Deputy Chief Medical Officer for England Jonathan Van-Tam said the (Witwatersrand) study did not change his opinion the that AstraZeneca vaccine was "rather likely" to have an effect on severe disease from the South African variant.[73]

The vaccine is stable at refrigerator temperatures and costs around US$3 to US$4 per dose.[74] On 17 December, a tweet by the Belgium Budget State Secretary revealed the European Union (EU) would pay €1.78 (US$2.16) per dose.[75]

According to AstraZeneca's vice-president for operations and IT, Pam Cheng, the company will have around 200 million doses ready worldwide by the end of 2020, and capacity to produce 100 million to 200 million doses per month once production is ramped up.[43]

In June 2020, further to making 100 million doses available to the UK's NHS, for their vaccination programme,[76] AstraZeneca and Emergent BioSolutions signed a US$87 million deal to manufacture doses of the vaccine specifically for the US market. The deal was part of the Trump administration's Operation Warp Speed initiative to develop and rapidly scale production of targeted vaccines before the end of 2020.[77] Catalent will be responsible for the finishing and packaging process.[78] The majority of manufacturing work will be done in the UK.

On 4 June 2020, the World Health Organization's (WHO) COVAX facility made initial purchases of 300 million doses from the company for low- to middle-income countries.[79] Also, AstraZeneca and Serum Institute of India (SII) reached a licensing agreement to supply 1 billion doses of the Oxford University vaccine to middle and low income countries, including India.[80][81] On 29 September 2020, a grant from the Bill and Melinda Gates Foundation allowed COVAX to secure an additional 100 million COVID-19 vaccine doses either from AstraZeneca or Novavax at US$3 per dose.[82]

On 13 June 2020, AstraZeneca signed a contract with the Inclusive Vaccines Alliance, a group formed by France, Germany, Italy, and the Netherlands, to supply up to 400 million doses to all European Union member states.[83][84][85] However, the European Commission intervened to stop the deal being formalised. It took over negotiations on behalf of the whole EU, signing a deal at the end of August.[86]

In August 2020, AstraZeneca agreed to provide 300 million doses to the US for US$1.2 billion , implying a cost of US$4 per dose. An AstraZeneca spokesman said the funding also covers development and clinical testing.[87] It also reached technology transfer agreement with Mexican and Argentinean governments and to produce at least 400 million doses to be distributed throughout Latin America. The active ingredients would be produced in Argentina and sent to Mexico to be completed for distribution.[88]

In September 2020, AstraZeneca agreed to provide 20 million doses to Canada.[89][90]

In October 2020, Switzerland signed an agreement with AstraZeneca to pre-order up to 5.3 million doses.[91][92]

On 5 November 2020, a tripartite agreement was signed between the government of Bangladesh, Serum Institute of India and Beximco Pharma of Bangladesh. Under the agreement Bangladesh ordered 30 million doses of Oxford-AstraZeneca vaccine from Serum through Beximco for $4 per shot.[93]

In November 2020, Thailand ordered 26 million doses of vaccine from AstraZeneca.[94] It would cover 13 million people,[95] approximately 20% of the population, with the first lot expected to be delivered at the end of May.[96][97][98] The public health minister indicated the price paid was $5 per dose,[99] which AstraZeneca (Thailand) explained in January 2021 after a controversy that the price each country paid depended on production cost and differences in supply chain, including manufacturing capacity, labor and raw material costs.[100] In January 2021, the Thai cabinet approved further talks on ordering another 35  million additional doses[101] and the Thai FDA approved the vaccine for emergency use for 1 year.[102][103] Siam Bioscience, a company owned by Vajiralongkorn, will received technological transfer,[104] and has the capacity to manufacture up to 200 million doses a year for export to ASEAN.[105]

Also in November, the Philippines made an agreement to buy 2.6 million doses,[106] reportedly worth around ₱700 million (approximately $5.6/dose).[107]

In December 2020, South Korea signed a contract with AstraZeneca to secure 20 million doses of its vaccine, reportedly worth equivalently to those signed by Thailand and the Philippines,[108] with the first shipment expected as early as January 2021. As of January 2021, the vaccine remains under review by the South Korea Disease Control and Prevention Agency.[109][110] AstraZeneca signed a deal with South Korea's SK Bioscience to manufacture its vaccine products. The collaboration calls for the SK affiliate to manufacture AZD1222 for local and global markets.[111]

On 7 January 2021, the South African government announced that they have secured an initial 1 million doses from the Serum Institute of India, to be followed by another 500,000 doses in February.[112]

Myanmar signed a contract with Serum Institute of India to secure 30 million doses of its vaccine in December 2020. Myanmar will get doses for 15 million people from February 2021.[113]

On 22 January 2021, AstraZeneca announced in the event the European Union approved the COVID-19 Vaccine AstraZeneca that due to production issues at Novasep in Belgium initial supplies would be lower than expected with only 31 million of the previously predicted 80 million doses to be delivered by March 2021, to the European Union.[114] In an interview with Italian newspaper La Repubblica, AstraZeneca's CEO Pascal Soriot said the delivery schedule for the doses in the European Union was two months behind schedule, stating low yield from cell cultures in one large-scale European site,[115] and analysis published in The Guardian also identifying an apparently low yield from bioreactors in the Belgium plant and noting the difficulties in setting up this form of process with variable yields often occurring.[116] As a result, the European Union imposed export controls on vaccine doses; controversy erupted as to whether doses were being diverted to the UK, and whether or not deliveries to Northern Ireland would be disrupted.[117]

• "Vaccines: contract between European Commission and AstraZeneca now published". European Commission.
• "How the Oxford-AstraZeneca Covid-19 Vaccine Works". The New York Times.