AstraZeneca blood clot worries complicate bid to vaccinate the world

Reviews by UK and EU regulators finding potential links to the unusual side effects are another blow for the shot, a cheaper and easier-to-deploy product that many nations are counting on

Growing worries that AstraZeneca Plc’s Covid-19 vaccine causes rare blood clots could hinder immunization campaigns across the world, from London to Seoul.
 

Reviews by UK and European Union regulators finding potential links to the unusual side effects are another blow for the shot, a cheaper and easier-to-deploy product that many nations are counting on in a bid to end the pandemic.

Safety concerns could shake confidence in the injection, even though regulators reiterated that its benefits outweigh the risks. Many regions are turning their attention to vaccines from Johnson & Johnson and developers in China, Russia and elsewhere, but they’re still in a difficult position with demand for doses far outstripping supply.

“Better Astra than nothing,” said Michael Kinch, a drug development expert and associate vice chancellor at Washington University in St. Louis. “In an under-vaccinated country, I think you have no choice but to take it.”

Scrutiny of the vaccine, developed by Astra and the University of Oxford, has been particularly intense in Europe, where skepticism about shots was already running high in places such as France and Poland. The UK on Wednesday recommended that people under the age of 30 should be offered alternatives, and countries across the EU have also imposed age restrictions.

High Stakes
 

Governments and regulators beyond Europe are watching closely, too, and in some cases taking action. There’s a lot at stake with Astra’s shot accounting for almost a quarter of the total supply deals signed for 2021, according to Airfinity Ltd., a London-based research firm.

Covax, an initiative designed to level global access that’s backed by groups including the World Health Organization, is highly reliant on the vaccine. Shots from Pfizer Inc. and Moderna Inc. are more expensive and harder to store. Covax is also leaning heavily on the Serum Institute of India Ltd. as a key supplier, but the country said last month it would slow down exports to focus on its own requirements.

The bigger dilemma for lower-income countries is they aren’t getting the supplies they need, said Birger Forsberg, associate professor of international health at the Karolinska Institutet in Stockholm. “When is that going to change?” he asked.

Even before the results of the latest reviews in Europe, South Korea moved to temporarily suspend Astra vaccinations for people under 60. Now the Philippines is opting for similar age restrictions.

Authorities in Canada, meanwhile, are reviewing the new guidance, as well as information submitted by the drugmaker, and will determine further steps later, federal health ministry spokesperson Anna Maddison wrote in an email. Canada in late March suspended plans to give the vaccine to people below the age of 55, citing blood clot concerns.

Regulators believe the vaccine is safe and effective and are leaving it up to individual countries to make their own decisions, according to Anthony Harnden, deputy chair of the UK’s Joint Committee on Vaccination and Immunization. For many countries, there aren’t a lot of alternatives.

“This is important for the whole world,” he said.

Countries in Africa, such as Namibia, Ivory Coast and Senegal, said they’ll go ahead with plans to administer the doses as they arrive, pointing to comments backing the vaccine from regulators and the WHO. Cameroon had previously stopped Astra inoculations.

“For Namibia this changes nothing,” health minister Kalumbi Shangula said. “It has not been conclusively demonstrated in clinical settings. We still plan to administer the vaccine when we get it.”

Link Likely
 

The UK’s move to avoid giving the shots to young adults follows an evaluation by the country’s Medicines and Healthcare Products Regulatory Agency that evidence of a link between the vaccine and the sometimes deadly clots is “stronger, but more work is still needed.”

Astra said it’s studying the individual cases to understand the “epidemiology and possible mechanisms that could explain these extremely rare events.” It’s also working with regulators on their request for new labels on its shots.

Astra shares rose 1.5% in London trading. While the company has pledged not to profit from the vaccine during the pandemic, some analysts have expressed concern that the vaccine’s woes may be a distraction for its top management.

UK health officials described the clotting syndrome as similar to a rare side effect of treatment with heparin, an anticoagulant, in which the body forms antibodies against blood platelets. How or why the vaccine might be involved in such a process is still under investigation.

The European Medicines Agency said that unusual blood clots with low platelets should be listed as very rare side effects, although the regulator didn’t issue any guidelines on age.

The EMA’s analysis was based on a review of 86 instances that had been reported as of March 22, including 18 fatalities. Some 25 million people had received the Astra shot in the UK and Europe by that point. On April 4, there had been 222 reported instances of that type of clotting out of about 34 million people, the agency said.

First Dose
 

So far, most of the cases occurred in women under the age of 60 within two weeks of vaccination. The events generally occurred after people received their first dose.

Many countries have populations that are significantly younger than in Europe, potentially pointing to a higher risk of the clotting, even if it remains very rare. For now, it’s unclear how the data will be interpreted globally, particularly in developing nations that had been banking on widespread use of the shot.

“I believe that the epidemiological data show that the natural infection is far worse than the severity of the side effects of the vaccine,” Washington University’s Kinch said.