Blood clotting from Johnson and Johnson Janssen vaccine 'really rare' - vaccinologist

A vaccinologist says you are more likely to experience blood clotting as a result of having Covid-19 than you are from Johnson and Johnson's vaccine.

Medsafe is expected to announce its decision on whether to approve the use of Johnson and Johnson's Janssen Covid-19 vaccine today.

However in the past few days the US, EU and South Africa have temporarily halted its use, over concerns about a rare type of blood clotting.

The government has an agreement to buy up to 5 million doses of the jab, with 2 million doses available from July.

Auckland University vaccinologist Helen Petousis-Harris told Morning Report blood clotting from this vaccine is "really rare".

"Medicines tend to come with risks and we seem to be seeing that there might be a risk associated with this particular vaccine. There are other vaccines that we have that also carry some risk with them and we need to be clear about what that is and if we are to use it, to tell people about what that risk is."

The risk for this vaccine at the moment appears to be that one in 1 million people have a blot clotting event, she said.

"We've really got to get that in context, if you were taking the birth control pill, that would be 500 to 1600 per million people [who experience blood clotting] which is huge but we don't get too hung up on that."

Blood clotting as a result of Covid-19 is experienced by 165,000 people per million, she said.

"This is an acceptable risk when you compare the risk of the disease," she said.

"The numbers still weigh heavily in favour of using the vaccine.

"If you think about the risk we take in our everyday lives, this vaccine is very safe."

It's important to have a backup vaccine for people who are unable to take the Pfizer vaccine, she said.