The pause on the Johnson & Johnson vaccine was lifted on April 23, 2021. SOPA Images/Light Rocket by way of Getty ImagesTwo vaccines – the Johnson & Johnson vaccine in the U.S. and the AstraZeneca vaccine in Europe – have been linked to an elevated probability of a uncommon sort of blood clot. Researchers are investigating what causes these clots and are beginning to suggest some solutions. Dr. Mousumi Som, a professor of medication at Oklahoma State University, explains what these uncommon clots are and the way they’re forming after folks get vaccinated. 1. What are the blood clots? A small quantity of folks in the U.S. have developed harmful blood clots after receiving the Johnson & Johnson vaccine. The clots have principally been occurring in folks’s brains and, paradoxically, are related to low platelet counts. Normally, platelets assist an individual cease bleeding once they get injured. If you get a minimize or have an harm, the physique responds by sending platelets which act as a brief patch. The patch attracts different platelets and so they stick collectively to cease blood loss. Since platelets usually assist the clotting course of, this mix of low platelets and excessive clotting makes these clots medically uncommon. These particular sorts of clots – referred to as cerebral venous sinus thrombosis – though uncommon, have an effect on round two to 5 folks per million per 12 months and are doubtlessly life-threatening with out therapy. Vaccines aren’t usually a set off for this type of clot. 2. Who is having these clots? As of April 24, 2021, out of the eight million folks vaccinated with the Johnson & Johnson vaccine in the U.S., about 16 folks have developed these blood clots. The clots occurred from six to 13 days after immunization, and the majority have been in girls between the ages of 18 and 48. On April 26, 2021, information reports indicated that no less than one man had developed a clot. The man is in his 30s and was hospitalized from a clot in his leg about two weeks after receiving the Johnson & Johnson vaccine. Health officers in Europe have additionally reported that the AstraZeneca vaccine – a COVID-19 vaccine approved and accredited in Europe however not in the U.S. – has induced about 200 circumstances of low-platelet clotting. Importantly, each the Johnson & Johnson vaccine and the AstraZeneca vaccine use a sort of innocent virus referred to as an adenovirus to ship directions to the human physique on how to construct an immune response to COVID-19. This known as a viral vector vaccine. The indisputable fact that the each vaccines use a viral vector and each are related to blood clots has led many well being consultants to assume that the clotting points of the two vaccines could share the identical mechanism. 3. Why are girls getting extra clots than males? At this level, medical doctors nonetheless don’t know what makes girls extra inclined than males, nor what places an individual in danger for these clots. These clots can happen, although not often, in individuals who don’t get a vaccine. Scientists know that girls are thrice extra seemingly to develop this kind of clot with out receiving the vaccine. Many researchers assume it is because of contraception or different hormonal replacements that girls take. 4. Why would possibly the vaccines be inflicting blood clots? Researchers consider that this particular low-platelet clotting is comparable to a response some people get once they obtain a blood thinner referred to as heparin, referred to as heparin-induced thrombocytopenia. Doctors generally use heparin to skinny an individual’s blood in the case of a coronary heart assault or a blood clot when blood circulate wants to be reestablished. But some folks expertise the reverse response, and their blood finally ends up clotting extra as an alternative. This occurs as a result of the physique triggers an undesirable immune response after receiving heparin. In these sufferers, heparin attaches to a product launched from platelets referred to as platelet issue 4. When this occurs, the immune system considers the mixed platelet issue Four and heparin an issue, so it creates antibodies in response. These antibodies connect to the heparin and platelet issue Four complicated, and the physique – which now thinks it wants to restore an harm – causes extra clotting whereas utilizing up much more platelets. This ends in the low platelet rely seen in these sufferers. When medical doctors have checked out the blood of sufferers who developed clots after receiving the Johnson & Johnson or AstraZeneca vaccine, it regarded very related to the blood of individuals who have the low-platelet clotting response to heparin. This has led scientists and medical doctors to consider that the identical course of is likely to be main to these clots attributable to the two vaccines.This article is republished from The Conversation, a nonprofit information web site devoted to sharing concepts from educational consultants. It was written by: Mousumi Som, Oklahoma State University. Read extra:Restart of the Johnson & Johnson COVID-19 vaccine: A health care provider explains why advantages far outweigh risksNo, vaccine unintended effects don’t let you know how effectively your immune system will shield you from COVID-19COVID-19 causes some sufferers’ immune methods to assault their very own our bodies, which can contribute to extreme sickness Mousumi Som works fr the Oklahoma State University Center for Health Sciences. She has acquired funding from Eli Lilly and NIAID for drug associated analysis on COVID remedies. She is affiliated with the National Board of Osteopathic Medical Examiners and the Osteopathic Founders Foundation. .