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Oxford-AstraZeneca’s cheap and easy-to-store vaccine has stepped up the global fight against the coronavirus, but fears over rare blood clots and production delays have hampered its rollout.
Here are five facts about the vaccine.
The AstraZeneca vaccine costs around £ 2.50 ($ 3.40) per dose and can be stored at refrigerator temperatures. This makes it ideal for large-scale vaccination programs.
According to AstraZeneca, the vaccine is approved in more than 70 countries.
More than 9.2 million shocks were administered in the European Economic Area, including the EU, Norway, Iceland and Liechtenstein.
Fears of blood clots
Cases of rare blood clots in vaccinated people have led many countries to stop or limit their introduction.
The European Medicines Agency (EMA) announced on March 31st that 62 cases of a rare coagulation disease, cerebral venous sinus thrombosis, had occurred worldwide, 44 of them in the European Economic Area.
In the UK, 30 cases of rare blood clotting conditions have been recorded and seven people have died.
AstraZeneca said in mid-March that there was “no evidence” of an increased risk of blood clots from its vaccine.
As a result, Denmark and Norway have suspended vaccinations.
Some countries rejected a number of vaccines after an Austrian nurse died of multiple thrombosis and another person suffered from pulmonary embolism after vaccination.
Many countries have only resumed use of the vaccine to older people aged 55 and over because the blood clots affected younger people.
These include France, Canada, Germany, the Netherlands, Finland, Iceland and Sweden, and Canada.
The EMA said on March 18 that the AstraZeneca push is safe and effective.
Some countries, including Estonia, Latvia, Lithuania, Luxembourg, Portugal, Italy, Ireland and Spain, resumed full rollout after confirmation by the EMA.
The EMA is expected to release updated recommendations on April 7th.
Delays in delivery
The vaccine was first approved for the general population in the UK, where 100 million doses were ordered.
In the EU, delivery delays have led to strong criticism of the Anglo-Swedish company.
AstraZeneca announced in January that it could deliver only a third of the 120 million doses originally promised to the 27 member states in the first quarter.
In March, Italy blocked the export of 250,000 cans to Australia, citing “persistent shortages” and “delays in delivery”, which was supported by the European Commission.
The EU member states are expected to receive 29.8 million doses of the AstraZeneca vaccine by the end of March, the European Commission said.
The vaccine is “virus-vectored,” which means that it is a version of a virus that normally infects chimpanzees and has been modified with part of the COVID-19 coronavirus called the “spike protein” to fire the immune system .
In human cells, the vaccine should help stimulate the production of antibodies that recognize the virus.
The vaccine is “safe and effective” according to data published in December by The Lancet Medical Journal. Only one out of 23,754 volunteers who took part in the studies had “potentially serious side effects associated with it”.
This was a case of a rare neurological disorder that forced studies to be temporarily suspended.
AstraZeneca announced in interim results in November that its vaccine was 70 percent effective on average, compared with more than 90 percent at Pfizer / BioNTech and Moderna.
The effectiveness of the AstraZeneca vaccine was 90 percent for volunteers who received only half a dose and then a full dose a month later, but only 62 percent for those in another group who vaccinated two full doses one month apart were.
Half a dose was injected by mistake, which raised criticism of the robustness of the results and prompted the company to conduct additional studies.
A recent study by the health authorities in England showed that people over the age of 70 protect between 60 and 73 percent of symptoms with a single dose.
Last month, AstraZeneca announced that a US study showed 79 percent effectiveness but revised that to 76 percent after US authorities raised concerns that some results were out of date.
The US has not yet approved their use domestically.
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© 2021 AFP
Quote: Five key pieces of information about the AstraZeneca / Oxford vaccine (2021 April 3), accessed April 3, 2021 from https://medicalxpress.com/news/2021-04-astrazenecaoxford-vaccine.html
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