The break in the administration of the Johnson & Johnson vaccine in the United States is extended by at least a week, a group of experts meeting Wednesday April 14 saying they need more time to assess its possible links with the training of severe blood clots.
The expert group met at the behest of the U.S. Centers for Disease Control and Prevention (CDC), America's leading public health agency, after the discovery of six cases of women, one of whom has died, having developed severe cases of blood clots associated with low levels of platelets after injection, in the United States.
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The Johnson & Johnson vaccine has already been given to 7.5 million people in the United States, and a seventh case, that of a 28-year-old woman, was raised during the meeting.
Experts could have decided to restrict the vaccine to parts of the population, but most said they needed to study more data before making a decision.
“I don't want anyone to suggest that there is something fundamentally wrong with this vaccine,”
said Beth Bell, chair of the expert panel.
“But I want to be able to understand and defend the decision I made based on a reasonable amount of data,”
The date of the next meeting has not been set, but is expected to take place in the next seven to ten days.
Some members of the group spoke out against keeping the hiatus, fearing it might have a stronger impact on vulnerable groups, easier to reach with this single-dose vaccine that can be stored in refrigerators.
But the majority considered that given the severity of blood clots, which can have devastating neurological consequences even when not fatal, and given the large stocks of other available vaccines, further study was needed.
Devastating neurological consequences
According to presentations made to the group, the first six cases identified were all in white women with no history of blood clots, and one was taking estrogen / progesterone oral contraceptive treatment.
The deceased woman was 45, and three of the women also had blood clots outside of the brain.
Even though the link to the vaccine has not been shown, scientists consider it to be the
of this phenomenon.
The symptoms are similar to the rare side effects seen after administration of the AstraZeneca vaccine in Europe, CDC director Rochelle Walensky said before the meeting.
The technology using an adenovirus for vector, used by the two vaccines as well as by the Russian Sputnik V and the Chinese CanSino, is now under surveillance.
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Individuals who have previously received the Johnson & Johnson vaccine should contact their doctor if they experience certain symptoms, such as migraines, abdominal pain, pain in the legs, or difficulty breathing.
Doctors have also been advised not to treat this type of blood clot with the usual anticoagulants, such as heparin, which has been shown to be dangerous in this situation.
Experts may at the next meeting recommend the Johnson & Johnson vaccine only to older people.
As they are more at risk of developing a severe form of Covid-19, it is in their best interest to be vaccinated despite the possible side effects.
But U.S. officials have stressed they have enough Moderna and Pfizer vaccines to meet the needs of the adult population by the end of July, which could allow them to do without the Johnson & Johnson serum.