Thai Premier Delays AstraZeneca Shot Over Probe Into Blood Clots

Thailand joined Italy and a number of other European nations in temporarily suspending the use of AstraZeneca Plc’s Covid-19 vaccine pending an investigation into whether it may trigger blood clots.

The decision comes even as European regulators renewed their support of the immunization developed by Cambridge-based AstraZeneca and the University of Oxford, saying there was no indication the shot caused the clots that occur in thousands of people every year.

It’s the latest setback for the vaccine, adding to confusion around its initial clinical study results and delayed deliveries in Europe that fueled a dispute with the U.K., where the company is based.

“These are the dilemmas that leaders face when vaccine safety events occur,” said Julie Leask, a professor of nursing and midwifery at the University of Sydney. “When vaccines are suspended due to such events, it can take a while for public confidence to return, even if the problem is later found to be unrelated. So these are never easy decisions.”

AstraZeneca did not immediately respond to requests for comment on Friday. The company previously said the safety of the vaccine was demonstrated in clinical trials, while a review of more than 10 million shot records found no evidence of increased rates of the clots that can lodge deep in the legs or turn deadly when they reach the lungs.

The conflicting messages highlight tension surrounding the rapid-fire rollout of vaccines to protect against Covid-19, which has already killed 2.6 million people around the world. While Astra’s shot hasn’t been conclusively tied to any serious complications, concerns about potential side effects have some nations hesitating over the inoculations that were developed and launched in less than a year.

Thai Premier Delays AstraZeneca Shot Over Probe Into Blood Clots

Exercising Caution

Many nations in Asia have already taken a more tentative approach to vaccinations, after largely containing the virus with intensive testing and tracing, social distancing and mask-wearing. The success allowed them to watch while other countries went first, ensuring that if serious complications arose they would be forewarned.

Widespread programs only began in recent weeks in many countries, even after the U.S. and the U.K. began mass inoculations in mid-December. Hesitancy around using the shots in Asia and Europe could derail some vaccination goals, potentially delaying the time it takes to fully protect the population.

Thailand’s Prime Minister Prayuth Chan-Ocha and some cabinet members who were scheduled to get AstraZeneca shots on Friday postponed their appointments after the suspensions in European countries, including Norway and Austria. That was the day Thailand was slated to begin its rollout of the vaccine, which accounts for 61 million of the 63 million doses the country ordered.

“In delaying the vaccination program, we’re not saying the AstraZeneca vaccine is bad or it’s faulty,” Yong Poovorawan, chief of the Center of Excellence in Clinical Virology at Chulalongkorn University, said during a Thai health ministry briefing on Friday. “We’re delaying it to see the safety reports and investigation into the blood clots.”

Piyasakol Sakolsatayadorn, adviser to the Thai health ministry’s vaccination program, said the Astra suspension would be short term -- potentially two weeks at the most -- and that the country would continue inoculating at-risk people with shots from China’s Sinovac.

Elsewhere in Asia-Pacific, Philippine health authorities concurred with European regulators, saying there was no reason to stop the rollout of Astra’s shot and that they were closely monitoring the situation. Australia won’t pause the rollout of the company’s vaccine, with Prime Minister Scott Morrison saying Friday that health authorities hadn’t raised any concerns about the shot and would continue to monitor developments overseas.

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