Covid-19: Why countries are suspending AstraZeneca vaccinations
Countries including France, Denmark, Ireland and Thailand have temporarily suspended their use of AstraZeneca’s coronavirus vaccine after reports that some people developed blood clots, although there is no proof that the shot was responsible.
The European Medicines Agency (EMA) and the World Health Organization (WHO) say the available data do not suggest the vaccine caused the clots and that people should continue to be immunised because the benefits outweigh the risks.
Here’s a look at what we know — and what we don’t.
What are the concerns?
Denmark was the first country to halt its use of the AstraZeneca Covid-19 vaccine last week after reports of blood clots in some people, including one person who developed multiple clots and died 10 days after receiving at least one dose. Danish health authorities said the suspension would last for at least two weeks while the cases were being investigated while also noting that, “at present, it cannot be concluded whether there is a link between the vaccine and the blood clots”.
Norway, Iceland, Bulgaria, Thailand, and Congo soon followed suit. On Saturday, Norwegian authorities reported that four people under the age of 50 who had received the AstraZeneca vaccine had an unusually low number of blood platelets, which could lead to severe bleeding. Shortly afterward, Ireland and the Netherlands announced that they were also temporarily halting their use of the AstraZeneca vaccine.
Most national health authorities underscored that the suspension of the AstraZeneca vaccine was strictly precautionary.
“We must always err on the side of caution, which is why it is sensible to press the pause button now as a precaution,” said Hugo de Jonge, the Dutch health minister.
Norwegian doctors announced Monday that one of the people hospitalised after getting the AstraZeneca vaccine had died. German officials said they would suspend its use after new reports of problems and based on the advice from its medicines regulator.
French President Emmanuel Macron said France would also suspend its use until the European health authority, the EMA, could review the vaccine, expected within days. Slovenia, Spain and Portugal also halted AstraZeneca vaccinations on Monday.
In response to the suspensions, AstraZeneca said it had carefully reviewed the data on 17 million people who received doses across Europe. It said there was “no evidence of an increased risk” of blood clots in any age group or gender in any country.
Is there proof the vaccine is responsible?
The EMA says there is “no indication that vaccination has caused these conditions”, adding that the number of reports of blood clots in people who received the AstraZeneca vaccine was no higher than for those who hadn’t gotten the shot.
In Britain, where 11 million doses of the AstraZeneca vaccine have been administered — more than any other country — there have been reports of about 11 people developing blood clots after getting a shot. None were proven to have been caused by the vaccine.
Some doctors pointed out that since vaccination campaigns started by giving doses to the most vulnerable people, those now being immunised are also more likely to already have health problems, making it more difficult to determine whether the vaccine is responsible.
Blood clots that form in the arms, legs or elsewhere can sometimes break free and travel to the heart, brain or lungs, causing strokes, heart attacks or a deadly blockage of blood flow.
Why did so many countries halt AstraZeneca vaccinations?
Anytime vaccines are rolled out widely, scientists expect some serious health issues and deaths to be reported — simply because millions of people are receiving the shots and problems could be expected to occur in a group so large. The vast majority of these end up not being connected to the vaccine, but because Covid-19 vaccines are still experimental, scientists must investigate every possibility that the shot could have some unforeseen side effects. The shots are considered experimental because the vaccines were only developed in the last year, so there is no long-term data for any of them.
“People die every day, and we have more than 300 million people globally who have been immunised who will die of other causes,” said Dr. Mariangela Simao, an assistant director-general at the WHO.
Is this a concern with other Covid-19 vaccines?
The EMA is currently examining whether Covid-19 shots made by Pfizer-BioNTech, Moderna and AstraZeneca might be causing low levels of blood platelets in some patients, a condition that could lead to bruising and bleeding.
Has AstraZeneca run into other trouble?
The vaccine has been approved for use in adults in more than 50 countries and has been proven to be safe and effective in research done in Britain, Brazil and South Africa. But there have been concerns raised about how the vaccine data have been released, and some European leaders, including French President Macron, have questioned the vaccine’s effectiveness.
Britain first authorised the vaccine based on partial results that suggested the shots were about 70 percent effective. But those results were clouded by a manufacturing mistake that led some participants to get just a half dose in their first shot — an error the researchers didn’t immediately acknowledge. When it recommended the vaccine be licensed, the EMA estimated the vaccine’s efficacy to be about 60 percent.
The data on whether the vaccine protected older adults were also incomplete, leading some European countries to initially withhold the shot from older people.
In the United States, the Food and Drug Administration suspended a study in 30,000 Americans for an unusual six weeks as frustrated regulators sought information about some possible side effects reported in Britain.
“All the data we have seen about the AstraZeneca vaccine suggests it’s very safe and is saving people from dying of Covid,” said Dr. Paul Hunter, a professor of medicine at the University of East Anglia. “But this may be more of a perception problem because every time there is a vaccine issue, we hear the name ‘AstraZeneca’ soon after.”