The rollout of the vaccine was briefly halted in Europe this week after several cases in which people who received the vaccine died. EU regulators allowed the use of the vaccine to resume later in the week, after determining the benefits far outweighed the risks. However, many individual countries continue to bar usage.
Researchers in Norway and Germany found the vaccine could trigger an autoimmune reaction that causes blood to clot in the brain, The Wall Street Journal reported. The research could lead to a possible treatment to prevent the problem, the paper said.
The studies have not been published or subjected to peer review, according to the report.
Symptoms of blood clotting, including dizziness and blurred vision appear several days after the vaccine is administered. However, the condition can be detected by a simple blood test and easily treated in a hospital, according to the report. The condition affects women far more than men.
Europe’s rollout of its vaccination program has lagged the U.S. The problems with the AstraZeneca vaccine have added to doubts and confusion just as authorities are trying to ramp up vaccinations. But with many countries now experiencing a third surge of COVID-19 cases, forcing renewed lockdowns, the pressure to vaccinate is only growing.
Shares of AstraZeneca rose 1 cent, or 0.02%, to $49.22 in after-hours trading Friday. The stock edged up for the week.
Stocks finished mixed on Friday with the Nasdaq rebounding as Treasury yields retreated following the Federal Reserve's announcement that it would allow a capital break for banks to expire.
The Dow Jones Industrial Average declined 234 points, or 0.71%, to 32,627, the S&P 500 eased 0.06%, while the Nasdaq gained 0.76%.