The covid-19 vaccine from AstraZeneca / Oxford is cheap and easy to store, but it is accumulating controversy, especially regarding side effects.
These are some of its main features:
– “Viral Vector” –
This vaccine was developed by researchers at Oxford University in collaboration with British pharmaceutical giant AstraZeneca.
It is a “viral vector” vaccine: it is based on another virus (a chimpanzee adenovirus) that was weakened and genetically modified to prevent the coronavirus from reproducing in the human body.
The way it introduces genetic material into cells, ordering them to attack SARS-CoV-2, has been described as a “Trojan horse”.
– Practical and affordable –
The AstraZeneca / Oxford vaccine has the advantage of being cheap (about 2.5 euros or $ 3 per dose, with variations depending on local production costs). AstraZeneca has promised to sell it without making a profit.
It is also easy to store: it can be stored at the temperature of a refrigerator, between 2ºC and 8ºC, unlike the Moderna and Pfizer / BioNTech vaccines, which can only be stored in the long term at very low temperatures.
This facilitates large-scale vaccination.
This drug is also distributed through the COVAX program in the most disadvantaged countries.
– Questions about side effects –
Suspicions are growing about possible serious, albeit uncommon, side effects after the detection of atypical thrombosis cases in patients vaccinated with AstraZeneca.
Dozens of cases have been reported, some of which have resulted in deaths.
The UK reported 30 cases and 7 deaths, so far, from a total of 18.1 million doses administered as of March 24th. No similar observations have been reported after the application of millions of doses of the Pfizer / BioNTech drug.
According to the European Medicines Agency (EMA), “no causal relationship has been proven, but it is possible,” and the benefits of the coronavirus immunizer continue to outweigh the risks.
As a precaution, several countries decided not to administer this vaccine below a certain age, such as Germany and the Netherlands (60 years), France and Canada (55 years), or Sweden and Finland (65 years).
For its part, AstraZeneca said in March that “there is no evidence of an aggravated risk.”
– Confusion about its effectiveness –
According to the British laboratory, it has an average efficiency of 70% (compared to more than 90% by Pfizer / BioNTech and Moderna), a result validated by the scientific journal The Lancet.
In the first published results, from clinical trials prior to approval, there were variations in efficacy, according to different doses administered by mistake, which sowed doubt and provoked criticism, leading the company to conduct additional studies. .
Its effectiveness in people over 65 was also questioned in Europe for lack of data, until new information, extracted from vaccination campaigns in the most advanced countries in this field, brought peace of mind in this regard.
In the United States, the drug regulator criticized the pharmaceutical group for providing “obsolete” data in its clinical trials. Therefore, it reduced its effectiveness to 76% in symptomatic cases, instead of 79%.
Two British studies conducted in real conditions, in Scotland and England, showed significant protection against hospitalizations.
– Delays in deliveries –
According to AstraZeneca, by mid-March, the vaccine was approved in more than 70 countries. The UK was the first to authorize it and ordered 100 million doses.
Delays in remittances to European Union countries provoked arduous complaints, as the lab itself delivered the promised stocks to the UK. Faced with this lack of supplies, the European Commission decided to control exports of vaccine vaccines to prevent deliveries to other countries.
This situation caused tensions between Brussels and London, but they have since pledged to resolve the dispute through negotiations.