WHO says ‘no indication’ AstraZeneca vaccine is linked to blood clots

No causal relationship has been established between the vaccine and the reported health problems, says health body

Samuel Lovett
Science Correspondent
Friday 12 March 2021 16:43
UK Covid-19 vaccinations: Latest figures
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The World Health Organisation has urged countries to continue administering doses of the Oxford/AstraZeneca coronavirus vaccine, saying there are no indications it is linked to the blood clots that have been reported in recent days.

Health authorities in Denmark, Norway, Iceland and others suspended the use of the vaccine this week after “thromboembolic events” were recorded in some people who had received the jab.

There is currently no evidence that the vaccine is responsible for the formation of these blood clots, which are not listed as side effects of the AstraZeneca jab.

The WHO said an expert advisory committee is currently reviewing the reports but insisted there is no reason not to use the jab.

“It’s very important to understand that, yes, we should continue to be using the AstraZeneca vaccine. All that we look at is what we always look at: any safety signal must be investigated,” Dr Margaret Harris, a spokesperson for the WHO, said during a press briefing on Friday.

She said it was an “excellent vaccine” and that no causal relationship had been established between the vaccine and the health problems reported, calling the pause in use “a precautionary measure”.

“It is very important we are hearing safety signals because if we were not hearing about safety signals that would suggest there is not enough review and vigilance,” Dr Harris added.

To date, there have been 30 reported thromboembolic events in Europe after the vaccine was administered, according to the European Medicines Agency.

The body is investigating the blood clots but said immunisation using the vaccine can continue during this review process, and that the jab’s “benefits … outweigh its risks”.

Around 5 million Europeans have already received the AstraZeneca vaccine, whereas this figure stands at 11 million for Britain.

The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) has also urged people to keep getting the vaccine when asked to do so.

It said there was no evidence to suggest the vaccine caused blood clot problems, which “can occur naturally and are not uncommon”.

“Reports of blood clots received so far are not greater than the number that would have occurred naturally in the vaccinated population,” said Dr Phil Bryan, MHRA vaccines safety lead.

Earlier on Friday, top German public health officials said the vaccine was safe, adding that the country would continue to deploy it.

With Germany still facing a scarcity of vaccines and a third wave of Covid-19, the government is anxious to ensure that vaccine scepticism does not undermine the rollout on which it is banking to bring the pandemic under control.

“Everything we know so far suggests that the benefits of the vaccine, even after every individual case reported, are greater than the risks, and that continues to be the case,” health minister Jens Spahn told a press briefing.

Professor Lothar Wieler, head of the Robert Koch Institute for Infectious Diseases, said that there was no statistical evidence of excess mortality after any coronavirus shot.

“Since we’re now vaccinating the old and very old, and most people who die are of course old and very old, then there can be a chronological link between vaccination and death,” he said.

“There is no evidence that the link is statistically excessive,” Prof Wieler added.

Portugal has meanwhile said that the benefits of the vaccine continued to outweigh any risk it poses to patients, and it would continue to use the jab. As with the WHO, it said it had identified no causal link between receiving the dose and developing blood clots.

Australia, which has already been sent 300,000 doses, has also said it intends to continue administering the AstraZeneca vaccine.

“At the moment the advice very clearly from the doctors is that this is a safe vaccine and we want the rollout to continue. Cool heads need to prevail,” said home affairs minister Peter Dutton.

AstraZeneca said in a statement on Friday: “An analysis of our safety data of more than 10 million records has shown no evidence of an increased risk of pulmonary embolism or deep vein thrombosis in any defined age group, gender, batch or in any particular country with Covid-19 vaccine AstraZeneca.

“In fact, the observed number of these types of events are significantly lower in those vaccinated than what would be expected among the general population.”

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