The AstraZeneca / Oxford covid-19 vaccine is inexpensive and easy to store, but is controversial, especially with regard to side effects.
These are some of the main features:
– “Vector viral” –
This vaccine was developed by researchers at the University of Oxford in collaboration with the British pharmaceutical giant AstraZeneca.
It is a “viral vector” vaccine: it is based on another virus (a chimpanzee adenovirus) that has been attenuated and genetically modified to prevent the coronavirus from reproducing in the human body.
The way it introduces genetic material into cells and directs them to attack SARS-CoV-2 is called a “Trojan horse”.
– Practical and affordable –
The AstraZeneca / Oxford vaccine has the advantage of being inexpensive (about 2.5 Euro or $ 3 per dose, with variations depending on local production costs). AstraZeneca has agreed to sell it without making a profit.
It’s also easy to store: it can be stored at 2 ° C to 8 ° C, unlike the Moderna and Pfizer / BioNTech vaccines, which can only be stored at very low temperatures for long periods of time.
This facilitates large-scale vaccination.
This drug is also distributed through the Covax program to the most disadvantaged countries.
– Questions about side effects –
Suspected serious but rare adverse reactions are raised following the detection of atypical cases of thrombosis in patients vaccinated with AstraZeneca.
Dozens of cases have been recorded, some of which have resulted in deaths.
The UK reported 30 cases and seven deaths so far out of a total of 18.1 million doses administered on March 24. No comparable observation has been reported after the application of millions of doses of the Pfizer / BioNTech drug.
According to the European Medicines Agency (EMA), “a causal relationship has not been demonstrated, but it is possible”, and the benefits of the coronavirus immunizer continue to outweigh the risks.
As a precaution, several countries have decided not to administer this vaccine under a certain age, such as Germany and the Netherlands (60 years), France and Canada (55 years), or Sweden and Finland (65 years).
AstraZeneca, for its part, said in March that “there is no evidence of an increased risk.”
– confusion about its effectiveness –
According to the UK lab, it has an average efficiency of 70% (compared to over 90% for Pfizer / BioNTech and Moderna), a result validated by the scientific journal The Lancet.
In the first published results, from clinical studies prior to their approval, there were variations in efficacy depending on the different accidental doses that raised doubts and raised criticism, forcing the company to conduct additional studies.
Its efficacy in people over 65 years of age was also questioned in Europe due to a lack of data, until new information derived from the vaccination campaigns of the most advanced countries in this field provided reassurance in this regard.
In the United States, the drug regulator criticized the pharmaceutical group for providing “outdated” data in its clinical studies. Therefore, it reduced its effectiveness to 76% in symptomatic cases, instead of 79%.
Two UK studies conducted under real conditions, in Scotland and England, showed significant protection against hospital admissions.
– Delays in deliveries –
According to AstraZeneca, the vaccine was approved in more than 70 countries in mid-March. The UK was the first to give consent and ordered 100 million doses.
Delays in remittances to European Union countries sparked fierce complaints as the lab delivered pledged shares to the UK. Faced with this lack of supplies, the European Commission decided to control exports of anticovid vaccines to prevent deliveries to other countries.
This situation created tensions between Brussels and London, but they have since pledged to resolve the dispute through negotiations.