No association can be found between the Covid-19 Pfizer vaccine and blood clots, according to a new study led by a Victoria University epidemiologist.
The findings were outlined in a study published today in Nature Medicine which observed 5.4 million people in Scotland who received either the Pfizer or AstraZeneca vaccine. Its lead author was Victoria University’s Professor Colin Simpson.
The study found the Pfizer Covid-19 jab was not associated with idiopathic thrombocytopenic purpura (ITP), a condition that affects the blood, nor was it associated with other clotting and bleeding events.
Someone with ITP has a low count of platelets, which are blood cells that form clots to stop people from bleeding when vessels are damaged. A low number of them can result in no symptoms, or can lead to an increased risk of bleeding or in some cases clotting.
Simpson said the findings are good news as New Zealand’s general population prepares to get vaccinated with the Pfizer vaccine in July.
Vaccine Alliance Aotearoa’s Graham Le Gros echoed the sentiment, telling Breakfast the study was "really incredible news" and that New Zealand was "very lucky" it chose Pfizer as its primary vaccine.
The study also found a small link between blood clotting and the AstraZeneca vaccine, with an estimated 11 in 1 million at risk.
Authors of the paper say the small risk associated with the AstraZeneca jab is important to note, but is far smaller than the risk of serious illness or death caused by Covid-19.
Le Gros said this showed there was a "bit of difference” between the Pfizer and AstraZeneca vaccines, but that the latter was still “incredibly good and safe”.
The study's authors also noted their study included "relatively few" people under 40 as the vaccination programme was still in the process of being rolled out in Scotland.
AstraZeneca’s Covid-19 vaccine, meanwhile, is on Medsafe’s approval queue .
The study was funded by the Medical Research Council, UK Research and Innovation Industrial Strategy Challenge Fund and Health Data Research UK, and was supported by the Scottish Government.