Filenews 2 April 2021
A new round of controversy has opened for AstraZeneca's vaccine following Germany and Canada's decision to suspend use in citizens under the age of 60.
1. How does the AstraZeneca vaccine work?
AstraZeneca's vaccine was made from an adenovirus, like those that cause the common cold, isolated from chimpanzees and modified so that it no longer reproduces in cells and therefore cannot infect humans. When injected, the vaccine gives "information" to human cells to produce the SARS-CoV-2 spike protein, which is the main target of the immune system against coronaviruses. Store at 2-8 degrees Celsius, i.e. in a simple refrigerator, and it is considered necessary to take two doses over 12 weeks.
2.What is its effectiveness?
Clinical studies have shown that the vaccine with both doses achieves on average 62% efficacy. A related publication in the reputable medical journal "The Lancet" concluded that when doses were administered within three months of each other the efficacy reached 82.4%, while it fell to 54.9% if the two doses were made less than six weeks apart. With regard to virus transmission, analysis of samples of nasal smears from asymptomatic and symptomatic vectors showed a 67% decrease in positive samples after administration of the first dose.
3.Why were the elderly initially excluded?
A small sample of older people was included in the first clinical studies, thus not clarifying its effectiveness at older ages. But the data from subsequent research convinced the scientific community. For example, the results from the London School of Public Health, which is concerned with EUR 7.5 million in 2005, are based on the results of the London School of Public Health. population from Great Britain. When the efficacy of the vaccine was tested in people over 70 years of age, an 80% reduction in risk was recorded from the first dose.
4.What is mentioned in the recently revised instruction leaflet?
'A combination of thrombosis and thrombocytopenia, in some cases accompanied by bleeding, has been observed very rarely after vaccination with the vaccine against AstraZeneca Covid-19. Health professionals should be alert for signs and symptoms of thromboembolism and/or thrombocytopenia".
5. What are the suspected symptoms that should lead those vaccinated to the hospital?
Vaccinated patients should be instructed to seek immediate medical attention if they experience symptoms such as shortness of breath, chest pain, lower limb swelling, persistent abdominal pain after vaccination. In addition, anyone vaccinated with neurological symptoms, including severe or persistent headaches and blurred vision after vaccination or showing skin bruises beyond the vaccination site from a few days ago, should seek immediate medical attention.
6.How many days after vaccination are thromboembolic events observed?
These are serious cases that occur as a combination of venous thrombosis (including unusual areas such as venous sinus thrombosis of the brain and thrombosis of the mesederic veins) or arterial thrombosis, with accompanying thrombocytopenia. The majority of these cases occurred within the first seven to fourteen days after vaccination and occurred in women under 55 years of age, however this may reflect increased administration of the vaccine in this population. It is noted that some incidents have ended up.
7. What is the mechanism that causes the side effects and scientists suspect?
As the Chair of the National Immunization Committee, Maria Theodoridou, recently pointed out, important steps have been taken in the scientific field to investigate the pathogenetic mechanism, since both Germany and Norway have formulated the theory of a pathogeneic mechanism based on autoimmunity, i.e. that antibodies attack antigenic positions of platelets, with the result that these platelet activation also results in the creation of clots and thrombocytopenia.
Therefore, as she added, there is "a basis, a basic mechanism that one can think of how to diagnose and inhibit him, since even the appearance of thrombocytopenic elements on the skin, can be an event that puts the suspicion of more investigation. This syndrome is analogous and known to hematologists as HEIT, it is related to the autoimmune mechanism of heparin". It stated that 'due to the mechanism created by this pathological condition, the administration of heparin and platelet transfusions is prohibited, while other anticoagulant agents, such as hypera immune g-globulin, may be administered'.
8.How often are thromboembolic events observed?
Cases have been reported following the administration of the vaccine against AstraZeneca Covid-19 infection in several countries of the European Economic Area, some of which have led to local commitments from specific batches, or even to suspension of use of the vaccine itself in the population as a whole or in specific population groups. More specifically, according to official data, there are 28 cases out of a total of 17 million doses of vaccines. Based on the above data, the probability in our country is one million vaccinations to record six to seven cases.
9.Why are vaccinations continuing?
According to the European Medicines Agency, the benefits of the vaccine in the treatment of Covid-19 disease (which itself produces thrombosis problems that can be fatal) continue to outweigh the risk of side effects. In addition, as has been noted the vaccine is not associated with an increase in the overall risk of thrombosis (thromboembolic events) in those administered. And they add that the causal relationship with the vaccine is not proven, but further analysis is possible and continues.
10. How many doses of the vaccine do they account for in Greece?
According to the National Operational Vaccination Plan against Covid-19 and under the EU agreement with the company, our country has "locked in" the supply of 7.1 million doses from AstraZeneca. As the chair of the National Immunizations Committee, Maria Theodoridou, pointed out earlier this week, "we hope that the control mechanisms in a short period of time will be able to give the right answers, the ones we are all asking for, in order to restore confidence in the AstraZeneca vaccine which, I repeat, is a powerful weapon for tackling the pandemic".
11. Is this the first time there have been doubts about this vaccine?
No. If we look back to November, then the first clinical trials of AstraZeneca's vaccine had shown that it has 90% efficacy. But soon after, when everyone started analysing the evidence, there was a lot of questioning. It was not about safety, of course, it was about efficiency. The participating volunteers were given different doses. 3,000 were given the first half dose and after 4 weeks a whole dose – here the effectiveness reached 90%. But in a larger group of 9,000 volunteers, who were given two full doses with a difference of 4 weeks, the effectiveness was 62%. This has caused confusion and a lot of debate, until the exact facts are clarified.
12. Which countries use the vaccine?
AstraZeneca vaccine is currently licensed in 86 countries. First in the UK in December and then in the EU states, Canada, India, Argentina, the Dominican Republic, El Salvador, Mexico and Morocco in January. So far 17 million doses of this vaccine have been administered in the EU and Britain.
13. In the US why isn't it used yet?
Because it has not yet been given the green light by the American authorities, by the Food and Drug Administration. A clinical trial with more than 30.00 volunteers is currently being conducted and conclusions are expected. The strange thing is that there are currently 30 million doses of this vaccine at an American plant at AstraZeneca's facility in West Chester, Ohio, awaiting approval, while other countries are facing a shortage.
14.Can this be a political issue?
At least that was hinted at yesterday by British newspapers highlighting Merkel and Macron's conversation with Putin and the debate over the possible arrival of the Russian Sputnik vaccine in the EU. Germany yesterday banned the use of the AstraZeneca vaccine in women under the age of 60, even though it has already vaccinated with the first dose of 2.2 million people.
15.Why did the vaccine change its name?
Practically the new name Vazxevria does not change much, as all vaccines have a name that is not used. For example Pfizer for Covid-19 is called Comirnaty, but no one knows. But negative publicity in recent times, with delays in delivery to the EU and possible side effects, seems to have certainly played a role, according to analysts in the name change. The change of packaging and name by the Swedish company is a common practice of marketing in disputed products. There is no doubt, however, that everyone will continue to call it the AstraZeneca vaccine.
Source: news.in.gr
