AstraZeneca finds no evidence of increased blood clot risk from vaccine

AstraZeneca Plc said on Sunday, March 14, a review of safety data of people vaccinated with its COVID-19 vaccine has shown no evidence of an increased risk of blood clots.

AstraZeneca's review, which covered more than 17 million people vaccinated in the United Kingdom and European Union, comes after health authorities in some countries suspended the use of its vaccine over clotting issues.

"A careful review of all available safety data of more than 17 million people vaccinated in the European Union and UK with COVID-19 Vaccine AstraZeneca has shown no evidence of an increased risk of pulmonary embolism, deep vein thrombosis, or thrombocytopenia, in any defined age group, gender, batch, or in any particular country," the company said.

“[World Health Organization] officials are currently investigating the matter to gain a full understanding of the events while the European Medicines Agency (EMA) stressed that there is no indication that the AstraZeneca shot is causing blood clots,” Concepcion said.

Precautionary measure
Several European countries postponed the AstraZeneca vaccine rollout as a precautionary measure last week, following reports that blood clots occurred in some people who had been inoculated with the British-Swedish COVID-19 shot. (See related story in World, Page A7)

Media reports also said a vaccinated patient in Denmark died after getting a blood clot, although it remained to be seen if the blood clot was directly caused by the AstraZeneca vaccine.

Thailand also postponed using the vaccine last week as a precaution, making it the first country outside Europe to do so, although the Public Health Ministry clarified that AstraZeneca is “still a good vaccine.”

The Philippines’ Department of Health (DOH) and Food and Drug Administration (FDA), meanwhile, said they would continue administering the AstraZeneca vaccine, noting there was “no indication for the Philippines to stop the rollout.”

Thailand can afford to suspend the vaccine rollout to make way for safety investigations because it has largely brought a second wave of coronavirus infections under control through quarantines and border controls, a Reuters report said, citing Kiattiphum Wongjit, permanent secretary for the Public Health Ministry in Thailand.

Concepcion is leading “A Dose of Hope,” an initiative that began with the private sector but later included local governments that also wanted to order AstraZeneca vaccines. The initiative has ordered and paid for 17 million doses of AstraZeneca so far.

But while Concepcion’s involvement in the initiative gives him an interest to defend AstraZeneca, health authorities abroad that don’t have a clear financial stake in the matter have also defended the vaccine.

The EMA, which is responsible for the scientific evaluation and safety monitoring of medicines in the European Union, said in a press release last week that there is “currently no indication that vaccination has caused these conditions,” noting that the vaccine’s benefits still “outweigh its risks.”

As of March 10, close to 5 million people had been inoculated with the AstraZeneca vaccine in the European Union. Out of that figure, the EMA noted that there are 30 cases of thromboembolic events, or blood clots.

“The number of thromboembolic events in vaccinated people is no higher than the number seen in the general population,” the EMA said.

“With Britain’s Medicines and Healthcare Products Regulatory Agency, they have stated that the reports of blood clots received so far are not greater than the number that would have occurred naturally in the vaccinated population—leading to a consensus that the benefits continue to outweigh the risks, which EMA, the [DOH] and Philippine [FDA] share,” Concepcion said.

Concepcion’s statement also cited Soumya Swaminathan, the WHO’s chief scientist, who said in a media report that it remains unclear if the vaccine is causing the blood clots.

“Just because it’s reported following a vaccination doesn’t mean that it’s because of the vaccination. It could be completely unrelated,” Swaminathan said in the report.