On Tuesday, experts at the European Medicines Agency (EMA), the group that evaluates and supervises medicines for the benefit of public health in the European Union (EU), is preparing to present the conclusions of their investigation into possible links between the Johnson & Johnson coronavirus vaccine and sporadic cases of unusual clotting disorders detected in the U.S.
Last week, J&J halted the European rollout of its one-dose vaccine after the U.S. Food and Drug Administration recommended that officials pause its use while examining the rare blood clot cases. Officials identified six cases of highly unusual blood clots among nearly 7 million people who received immunization shots in the U.S.
The recommendation to halt the use of the J&J vaccine also dealt a severe blow to African countries. Many African countries were relying on vaccines from J&J and AstraZeneca to stop the spread of COVID-19. Like the J&J vaccine, it appears the AstraZeneca vaccine also causes severe clotting – especially in younger adults. African countries have a significantly younger population than developed countries.
J&J advised European governments to store their doses until the EU drug regulator issued guidance on their use; widespread use of the shot in Europe has not yet started.
The delay was a further blow to vaccination efforts in the European Union, where supply shortages, logistical problems, and concerns over unusual blood clots in a small number of people who received the AstraZeneca COVID-19 vaccine were hurting efforts to stop the spread of the virus. Experts worry the temporary halt on J&J’s shot could further shake vaccine confidence and complicate worldwide COVID-19 immunization efforts.
Last week, South Africa suspended its use of the vaccine in the wake of the U.S. pause, and several countries, including Italy, Romania, the Netherlands, Denmark, and Croatia, also decided to put their J&J doses into storage.
The blood clots linked to the J&J vaccine occur in unusual parts of the body, such as veins that drain blood from the brain. Those patients also have abnormally low blood platelets, a condition generally linked to bleeding, not clotting.
With the AstraZeneca vaccine, scientists in Norway and Germany have suggested that some people experience an abnormal immune system response, forming antibodies that attack their platelets.
It’s not yet clear if there might be a similar mechanism with the J&J vaccine. The J&J and AstraZeneca vaccines and a Russian COVID-19 vaccine, and one from China are made with the same technology. They train the immune system to recognize the spike protein that coats the coronavirus. To do that, they use a cold virus, called an adenovirus, to carry the spike gene into the body.
Earlier this month, the EU drug regulator said there was a “possible link” between the AstraZeneca shot and rare blood clots but said the benefits of vaccination far outweigh the risks of COVID-19. It noted the risk is less than the blood clot risk than healthy women face from birth control pills.