Peter Openshaw, an Imperial College London immunologist and member of the Covid-19 clinical information network, told BBC Radio 4’s Today programme on Saturday that “we still don’t know whether they are directly related and caused by the vaccine, but it seems possible that they could be.”
A scientist advising the government has said that any blood clots associated with the Johnson & Johnson vaccine – and other coronavirus jabs using similar technology – are “extraordinarily rare events”.
Four people in America have suffered serious cases of a rare blood clotting condition after receiving the US-made inoculation, it has emerged, echoing a number of cases and fatalities seen in Europe in people who have received the Oxford/AstraZeneca jab in recent weeks.
Prof Openshaw said it was essential to bear in mind how rare these events are, particularly given the “massive scale” and scrutiny of the global vaccine rollout.
Asked whether he was concerned that the cases could undermine public confidence in coronavirus jabs, Prof Openshaw said: “These are extraordinarily rare events and there is no medicine that is going to be completely free of side effects.
“But this is on the scale of the risk of adverse outcome you would expect if you get into a car and drive 250 miles, and many of us wouldn’t blink before taking that risk.”
The Johnson & Johnson, AstraZeneca, and Russia’s Sputnik V vaccines are all adenoviral vaccines.
“These are common adenoviruses that cause frequent infections, but they’ve been genetically modified or disabled or selected in order to be very benign, but also to carry the spike protein of the coronavirus,” Prof Openshaw said.
“It’s a very ingenious way of delivering the spike protein in a way that the body will learn to recognise the spike protein immunologically and will therefore mount a natural defence against infection with SARS-CoV-2 and will prevent Covid.”
A number of European countries have limited their use of the AstraZeneca vaccine following reports of rare blood clots – with dozens of cases, some fatal, reported in the tens of millions of people to have received doses.
