An American study shows that the AstraZeneca vaccine is effective, says Michael Head of the University of Southampton. But its effectiveness against the South African variant is not yet proven.
The Oxford-AstraZeneca vaccine has been the subject of a real political debate in recent months, especially within the European Union (EU). His efficiency, to security and availability have raised concerns that seem to have reduces confidence Population.
The Oxford-AstraZeneca vaccine is one of the main COVID-19 vaccines now available. It is therefore essential that it be accepted by the general public. The latest data from phase 3 trial for this vaccine, originating in the United States, could potentially help allay some previous concerns about efficacy and safety. But even these results have been called into question. In Canada, the vaccine has already been approved and Health Canada reiterated its confidence towards him, despite questioning the results of the trials in the United States.
This American trial involved more than 32 people, of whom more than 000 received at least one dose of the vaccine. Preliminary results - yet to be peer reviewed - suggest that when given four weeks apart, two doses show 21% effectiveness in preventing Covid-000 symptomatic and 79% in the prevention of serious illness and hospitalization.
We can say that these new results correspond entirely to expectations, since they are comparable to previously published results. However, the independent data and safety oversight committee that reviewed the trial worries that AstraZeneca may have included "outdated information" in its analysis, thus providing "an incomplete view of the efficacy data". The situation should clear up in the next few days.
This is undoubtedly a setback. The vaccine has not yet been authorized in the United States, and these latest developments may further delay this process. However, while these US results are subject to change, the overall picture they paint remains positive in light of concerns previously raised in Europe: they provide additional evidence that the vaccine is safe and works in people. the elderly.
The American results come after a particularly hectic week for this vaccine. In a few days, around March 15, a number of countries - mainly in Europe, including Germany and France - have suspended use of the vaccine, while a possible link to a rare type of blood clotting, cerebral sinus venous thrombosis, has been reported in 18 recently vaccinated people.
Throughout this investigation, the European Medicines Agency (EMA) and the World Health Organization have recommended continuing the deployment, as has the International Society of Thrombosis and Hemostasis. The breaks, taken amid rising infections in many European countries, will undoubtedly lead to more hospitalizations, deaths and long-term symptoms related to Covid-19. THE'EMA announced last week that it had found no causal link, but since then not all countries have resumed use of the vaccine.
Against this background, it is a good thing that the data from the US trial did not reveal any new safety concerns, including the risk of thrombosis or events characterized by thrombosis. Of course, a sample of 21 people cannot be representative, since rare adverse events such as cerebral venous sinus thrombosis, normally occur at a rate of only five cases per million people. But this new series of verifications comes on top of the itself vaccine safety, and we hope it will help convince countries to start protecting people with it again.
Another question arises: will the breaks in countries that have suspended the use of the vaccine will increase the reluctance to be vaccinated, either for the product of Oxford-AstraZeneca or for other vaccines against the Covid-19?
France is generally the most vaccine-reluctant country in Europe outside of a pandemic, and a recent YouGov poll revealed that 61% of French people think the Oxford / AstraZeneca vaccine is dangerous. This is an increase of 18 percentage points in one month.
Similar results were obtained from respondents in Germany - 55% of them considered it dangerous, an increase of 15 percentage points - as well as in Spain and Italy. Even in the UK, which has administered more than 10 million doses of the vaccine and where confidence remains high, reports report an increase in absences from appointments and requests for the Pfizer vaccine instead. The safety report from the United States is therefore welcome, as the confidence of individuals clearly needs to be enhanced.
The results press release also points out that about 20% of the participants in the US trial were aged 65 and over, and in that age group the effectiveness was 80%. It can also help build confidence.
Another critical concerning this vaccine is that it has not been sufficiently tested in the elderly. The decision to authorize the vaccine in the UK was based on limited data regarding its effects in those over 55. Indeed, this lack of data has led some European countries not to initially recommend the use of the vaccine in the elderly, which may also have undermined trust people towards him.
Vaccination is an important weapon against the Covid-19 pandemic and against any major epidemic. Concerns remain about the impact of the coronavirus variants, which call into question the effectiveness of this vaccine, in particular the variant B1351 first observed in South Africa. Likewise, we need to clarify the exact results of the US study in terms of efficacy, given the concerns raised by the trial's data oversight and safety committee.
Despite these problems, the Oxford-Astrazeneca vaccine is very effective and important. Given its price, its relative ease of storage and its production in such large numbers, it remains an important tool in the fight against Covid-19 on a global scale.