The European Medicines Agency (EMA) safety committee today released the conclusions of its preliminary probe of blood clotting reports in people who received the AstraZeneca-Oxford COVID-19 vaccine. The committee said immunization benefits still outweigh the risks, but may be linked to extremely rare cases of clots linked to low blood platelets, especially in those younger than 55.
The eagerly awaited findings come in the wake of vaccine program suspensions in nearly 20 countries, mostly in Europe. Countries such as Austria, Norway, and Germany reported a small number of suspected side effects, prompting the pauses, ordered mainly as a precaution during the EMA’s investigation. The problem is the latest hurdle in Europe’s fight against COVID-19, with the region grappling with vaccine supply problems and it faces the rapid spread of more transmissible SARS-CoV-2 variants.
No overall risk increase, but can’t rule out rare instances
The EMA concluded that the vaccine isn’t linked to an overall increase in blood clots or a problem with specific batches. However, it added that it may be associated with very rare cases associated with thrombocytopenia, including rare cases of blood clots in vessels draining from the brain (CVST).
Of about 20 million people in Europe who have received the vaccine, the EMA reviewed reports of 7 cases of disseminated intravascular coagulation (DIC) and 18 cases of CVST. They found that the overall number of thromboembolic events during clinical trials and after vaccine rollout was lower than expected in the general population, which led to the conclusion that there’s no increase in the overall risk. The group also pointed out that COVID-19 infection itself can cause clotting problems, which can be fatal.
However, they had some concerns about the reports involving younger patients. Most occurred in people younger than 55, and most were women. The EMA said it’s difficult to calculate background rates of blood clotting conditions in unvaccinated people in COVID-19 settings, but it said based on pre COVID-19 estimates, less than 1 DIC case would be expected in people younger than 50 within 14 days of vaccination, though 5 have been reported. They saw a similarly higher pattern for CVST in the younger age group, which wasn’t seen for older adults.
Though the AstraZeneca-Oxford vaccine is effective at preventing hospitalization and death from COVID-19, patients should be notified of the remote possibility of blood clotting problems and seek immediate medical attention for certain symptoms.
The EMA said steps are already underway to update the product label with the warnings, adding that it will take more steps to assess the risks, including if the conditions are associated with other COVID-19 vaccines. So far, no signals have been seen for the other vaccines.
UK regulators find no link, continue to examine reports
In a related development, the United Kingdom regulators, the Medicines and Healthcare Regulatory Agency (MHRA) today said that a rigorous review by its safety working group also found that the vaccine’s benefits far outweigh the risks and that people should get vaccinated. It noted that a further review of five UK reports of blood clots in the cerebral veins with thrombocytopenia is ongoing. It added that the cases amount to less than 1 in 1 million people vaccinated.
As the investigation continues, the MHRA urged people who have experience a headache lasting longer than 4 days after vaccination or those with bruising beyond the vaccination site to seek medical attention.
Andrew Pollard, MBBS, PhD, chief investigator of the Oxford Vaccine Trial, said he welcomed the news that the EMA and MHRA emphasized that the vaccine’s benefits outweigh any potential risks, according to Reuters.
The World Health Organization (WHO) global vaccine safety committee is also reviewing the blood clot reports this week, and yesterday it said the AstraZeneca-Oxford vaccine’s benefits outweigh the risks, and it urged countries to continue their vaccine campaigns.
Other global headlines
- Brazil yesterday reported its highest single-day case number since the start of the pandemic, registering 90,303 new cases, along with 2,648 more deaths, according to CNN.
- Pakistan is also among the countries reporting new surges, and yesterday reported its highest daily case number since early December, with most of the cases from Punjab state and the country’s finance minister warning about the spread of the more transmissible variant.
- European countries also reported more spikes, including Germany with its biggest daily rise in 2 months, Poland reporting its highest daily total of the year, and the Ukraine imposing a 3-week lockdown for Kiev to blunt its latest surge.
- A World Meteorological Organization task force released a report today that said weather and climate conditions, especially the onset of higher temperatures in the Northern Hemisphere as spring approaches, shouldn’t be used to trigger relaxing measures in place to control COVID-19. It added that transmission in 2020 and early 2021 was influenced by government interventions such as mask mandates and travel curbs, rather than weather factors. The group said other relevant drivers include changes in human behavior, population demographics, and virus mutations.
- The global total today passed 121 million cases and has now reached 121,575,169, with 2,685,554 deaths, according to the Johns Hopkins online dashboard.