AZ publishes new real-world safety data for COVID-19 vaccine Vaxzevria

AstraZeneca has revealed new real-world data in a bid to continue establishing the ‘favourable’ benefit-risk profile of its COVID-19 vaccine Vaxzevria.

Data from one real-world study, published as a pre-print on The Lancet server, contained analysis from over one million people assessing the incidence rates of the blood clotting disorders thromboembolism and thrombocytopenia, including very rare cases of thrombosis with thrombocytopenia (TTS), following vaccination with Vaxzevria or a mRNA-based vaccine.

This was then compared to expected rates in a general population and also in people with COVID-19.

According to AZ, the safety profiles of Vaxzevria and the undisclosed were similar and ‘overall favourable’, with cases of TTS disorders observed with both vaccines. AZ added that the incidence of rare blood clot disorders were in line with what would be expected in the general population and also lower than in those with COVID-19.

Although follow-up time was not sufficient to report rates after two doses of Vaxzevria, AZ also released additional data showing rates of TTS following a second dose of the vaccine are comparable to the background rate in an unvaccinated population.

The data, gathered using a global safety database, found the estimated rate of TTS following a second dose of AZ’s jab was 2.3 per million vaccinees, which was comparable to the background rate.

However, the rate jumped to 8.1 million vaccinees after the first dose, AZ added in a statement.

“This real-world study offers further evidence of the favourable benefit-risk profile of Vaxzeria and demonstrates the critical role all COVID-19 vaccines are playing in combatting the pandemic,” said Mene Pangalos, executive vice president of BioPharmaceuticals R&D at AZ.

Earlier this month, The Wall Street Journal reported that AZ, The University of Oxford and Johnson & Johnson, alongside outside scientists, are planning to conduct early research into the potential of modifications to their vaccines to reduce or remove the risk of rare but serious blood clots associated with the jabs.

AZ said it is “actively working with the regulators and scientific community to understand these extremely rare blood-clotting events, including information to drive early diagnosis and intervention, and appropriate treatment”.

According to data from both the UK and Europe, the rate of the rare blood clotting issue –  referred to by some scientists as vaccine-induced immune thrombotic thrombocytopenia (VITT) – is around one to two cases per 100,000 doses for the AZ vaccine.