Astra, Oxford Said to Look at Adapting Vaccine Against Clot Risk


AstraZeneca Plc and scientists from the University of Oxford are looking at whether their Covid-19 vaccine can be modified to prevent rare blood clots, according to a person with knowledge of the situation.

The scientists are doing early-stage research on whether the shot can be tweaked in any way to reduce or remove the risk of the side effect, though there is no formal program or funding in place for the investigations at this stage, said the person, who didn’t want to be identified because the research hasn’t been discussed publicly.

A number of countries suspended use of the Astra shot earlier this year after it emerged that some recipients had developed a rare combination of blood-clotting in the brain with low levels of platelets, which had proved fatal in a small number of cases. Regulators later confirmed there was an association between the vaccine and the condition, with some countries like the U.K. amending guidance and limiting use of the shot to certain age groups deemed at lower risk. Similar infrequent side effects have occurred with the Covid-19 vaccine created by Johnson & Johnson, which also uses an adenoviral technology.

A spokesperson for Astra said the company was “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.” A spokesman for Oxford didn’t immediately respond to a request for comment.

The research was first reported by the Wall Street Journal, which said J&J was also looking at modifications to reduce the risk of clots. A spokesperson for J&J declined to comment on whether it was conducting such investigations, saying in a statement only that the company supports “continued research and analysis” to help with awareness of the rare side effects.

The majority of the blood clots with concurrent thrombocytopenia in the U.K. emerged after the first dose of the Astra vaccine, which requires two shots. As of the end of June, 399 cases had been reported to the British regulator, including 71 deaths.

Drugmakers like Astra and Oxford are also actively researching how their shots can be amended to better tackle virus variants. Astra said previously that it hopes to have a new version ready by the autumn.

©2021 Bloomberg L.P.

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