A Norwegian medical team looking into the cases of three health workers who were hospitalized after being administered the AstraZeneca coronavirus vaccine, one of whom died, has said they were probably linked to an immune response triggered by the inoculation.
Norway suspended use of the AstraZeneca vaccine a week ago, with its regulator citing two deaths and two other cases of hospitalization involving severe blood clots among about 130,000 people who had been vaccinated.
“Our findings support the early theory that the patients had a strong immune response, which [led] to antibody creation, which can ignite blood platelets and cause a thrombosis,” Pal André Holme, the lead doctor on the Oslo University Hospital coronavirus team, told reporters Thursday. Three of the patients were treated at this facility. The case involving the second fatality was handled elsewhere and not included in the Oslo University Hospital team’s investigations.
Holme said he could not say for sure that the vaccine caused the clots but added, “I see no other possibility as of today.”
The patients, all under the age of 50, also had a low platelet count. AstraZeneca has said that 37 instances of blood clots among the 17 million people administered the shots worldwide constitutes a lower rate than one would expect to see in the wider population. But Norway’s regulator has said the types of clots seen are extremely unusual.
In response to questions on the Norwegian team’s findings, AstraZeneca said that British and European regulators maintain that the vaccine’s benefits outweigh the risks.
While affirming confidence in the AstraZeneca vaccine, Europe’s medical regulator is investigating whether the instances of the clots are linked to the inoculations. It will present its findings Thursday.
Holme said he had not seen a similar response caused by other vaccines in the past. He said his team is looking at whether the three health workers shared any underlying conditions that might explain why they reacted to the vaccine in such a way.