The U.S. government on Tuesday advised states to suspend the application of the dose
The main suspect in the investigation of extremely rare cases of thrombosis after the use of two similar coronavirus vaccines (Johnson & Johnson and AstraZeneca) is a rare and unpredictable immune response.
The US government on Tuesday advised states to suspend the Johnson & Johnson vaccine because the authorities have checked six of the 6.8 million Americans who have been vaccinated so far, including one death.
But a small number of cases have caused concern because just last week, European authorities stated that similar cases of thrombosis may be related to the AstraZeneca vaccine that has not yet been licensed for use in the United States. This has resulted in certain countries/regions restricting apps for certain age groups.
Also on Tuesday, Johnson & Johnson postponed the release in Europe.
What makes these different?
These thrombi are not typical, but they are unique in two ways.
First, they occur in abnormal parts of the body, such as the veins that drain blood from the brain. Second, these patients have abnormally low platelet levels, which are usually related to bleeding rather than clotting. Platelets are cells that help blood clot.
Scientists in Norway and Germany are the first to propose the possibility that some people’s immune systems will react abnormally to the AstraZeneca vaccine, thereby forming antibodies that attack their own platelets. Dr. Peter Marks, director of vaccination at the U.S. Food and Drug Administration (FDA), said that this is the hypothesis when the United States is now investigating thrombosis cases receiving the Johnson & Johnson vaccine.
Why suspect an immune response?
The first clue: the widely used blood thinner called heparin sometimes causes similar side effects. Dr. Geoffrey Barnes, a thrombosis expert at the University of Michigan, said that in rare cases, heparin receptors can form antibodies that attack and overstimulate platelets.
Barnes said: “It can cause bleeding to clot both ends of the spectrum.”
Since heparin is often used in hospitals, this response is that “all hospitals in the United States know how to diagnose and treat.”
In people who have never taken heparin (such as after infection), this strange combination of low-clotting platelets is rarely reported. According to Barnes, the unexplained cases did not cause widespread concern until the first reports of thrombosis in some people with the AstraZeneca vaccine surfaced.
Health officials said one reason for Johnson & Johnson’s vacation is to make sure that doctors know how to care for patients when they suspect that patients have blood clots, including not giving them heparin.
The Centers for Disease Control and Prevention (CDC) on Tuesday issued recommendations on how to detect and treat these rare blood clots.
What does the survey reveal?
In two studies published last week in the New England Journal of Medicine, research teams from Norway and Germany detected antibodies that attacked certain people who received the AstraZeneca vaccine and had strange blood clots. Platelets in the blood. The antibody is similar to the antibody found to be a side effect of heparin, although the patient has never used this anticoagulant.
It is not clear whether there is a similar connection with Johnson & Johnson vaccine. However, vaccines from Johnson & Johnson and AstraZeneca, as well as Russian and Chinese vaccines against COVID-19, are manufactured using the same technology. These vaccines train the immune system to recognize the spike protein covering the coronavirus. To do this, they used an influenza virus called adenovirus to introduce the spike gene into the body.
The FDA logo does not state whether thrombosis cases are common in so-called adenoviral vector vaccines. With the exception of AstraZeneca’s data, Johnson & Johnson produces Ebola vaccines in the same way, and Max said the authorities will check “all evidence.”
What about other vaccines?
The most widely used anti-coronavirus vaccine produced by Pfizer and Moderna in the United States is produced using completely different technologies. The FDA stated that there is no evidence of similar cases of thrombosis.
What about those who are worried about buying Johnson & Johnson vaccines? Max said it is important not to confuse the extremely rare risk of thrombosis with the flu-like symptoms that people usually experience one or two days after vaccination. He pointed out that one to three weeks after taking the Johnson & Johnson vaccine (single dose), headache symptoms such as severe headache or severe abdominal pain may occur.