Growing fears that AstraZeneca Plc’s Covid-19 vaccine will cause rare blood clots could hamper vaccination campaigns across the world, from London to Seoul.
Reviews from UK and EU regulators finding potential links to the unusual side effects are another blow, a cheaper and easier to deploy product that many countries are counting on to end the pandemic.
Safety concerns following growing reports of blood clots in people who have received the inoculation could shake confidence, even though regulators have agreed that the benefits outweigh the risks. Although many regions are turning to vaccines from Johnson & Johnson and developers in China, Russia and elsewhere, they are in a difficult position with demand for doses far greater than supply.
“Better Astra than nothing,” said Michael Kinch, 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.”
The review of the vaccine, developed by AstraZeneca and the University of Oxford, has been particularly intense in Europe, where skepticism about injections was already high in countries like France and Poland. The UK on Wednesday recommended that people under 30 be offered alternatives to the Astra vaccine, and EU countries have also imposed age restrictions.
Governments and regulators elsewhere are also monitoring closely and, in some cases, taking action. The stakes are high, with AstraZeneca’s shot accounting for nearly a quarter of total supply agreements signed for 2021, according to Airfinity Ltd., a London-based research firm.
Covax, an initiative designed to level global access and supported by groups such as the World Health Organization, relies heavily on the AstraZeneca vaccine. Photographs from Pfizer Inc. and Moderna Inc. are more expensive and more difficult to store.
Even before the results of the latest reviews in Europe, South Korea has decided to temporarily suspend AstraZeneca vaccinations for people under the age of 60.
Canadian officials, meanwhile, are reviewing the new guidelines, as well as information submitted by AstraZeneca, and will determine next steps later, Federal Health Department spokeswoman Anna Maddison wrote in an email. Canada suspended its intention to give the vaccine to people under the age of 55 at the end of March, citing problems with blood clots.
Regulators believe the vaccine to be safe and effective and leave it to each country to make its own decisions, according to Anthony Harnden, vice chairman of the UK Joint Committee on Vaccination and Immunization. There aren’t many options for many countries.
“It’s important for the whole world,” he said.
Countries in Africa, such as Namibia, Cote d’Ivoire and Senegal, have said they are moving forward with plans to administer the doses when they arrive, highlighting comments supporting the vaccine from regulators and of the WHO. Cameroon had previously stopped inoculations of Astra.
“For Namibia, it doesn’t change anything,” Namibian Minister of Health Kalumbi Shangula said. “This has not been conclusively shown in a clinical setting. We still plan to administer the vaccine when we receive it.”
The UK’s decision to avoid giving the vaccines to young adults follows an assessment by the country’s Medicines and Health Products Regulatory Agency that evidence of a link between the vaccine and clots sometimes fatal is “stronger, but there is still work to be done”.
AstraZeneca said it is studying individual cases to understand “the epidemiology and possible mechanisms that could explain these extremely rare events.” He is also working with regulators on their request for new labels in his photos, he said in a statement.
British health officials have described the coagulation syndrome as being similar to a rare side effect of treatment with heparin, a blood thinner, 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 unusual blood clots with low platelets should be listed as very rare side effects, although the regulator does not issue age guidelines.
The EMA’s analysis was based on a review of 86 cases reported as of March 22, including 18 deaths. Some 25 million people had received the Astra gunshot in the UK and Europe by that time. As of April 4, 222 cases of this type of coagulation had been reported in about 34 million people, the agency said.
So far, most cases have occurred in women under the age of 60, occurring within two weeks of vaccination. The events typically happened after people received their first dose, so it’s not clear how a second dose might affect people, health officials said.
Many countries have populations that are significantly younger than in Europe, which could indicate a higher risk of coagulation, although this is still very rare. At this time, it is unclear how the data will be interpreted globally, especially in developing countries that had relied on widespread use of the shot.
“I believe the epidemiological data shows that the natural infection is much worse than the severity of the side effects of the vaccine,” said Kinch of the University of Washington.
– With the help of Pius Lukong, Katarina Hoije, Kaula Nhongo, Antony Sguazzin and Ilya Banares.