Doctors home in on cause of blood clots potentially linked with Covid-19 vaccines

A group led by Dr. Marie Scully, a hematologist at University College London Hospitals, studied 22 sufferers who developed the syndrome after receiving AstraZeneca’s vaccine, and located they’d an uncommon antibody response. These so-called anti-PF4 antibodies had solely been seen earlier than as a uncommon response to the use of the frequent blood thinner heparin.

If vaccines cause it, it is nonetheless very uncommon and weird, they wrote. It won’t even be occurring any extra typically in not too long ago vaccinated folks than among the many inhabitants in normal.

“The risk of thrombocytopenia and the risk of venous thromboembolism after vaccination against SARS-CoV-2 do not appear to be higher than the background risks in the general population, a finding consistent with the rare and sporadic nature of this syndrome,” they wrote.

“The events reported in this study appear to be rare, and until further analysis is performed, it is difficult to predict who may be affected. The symptoms developed more than five days after the first vaccine dose,” they added.

“In all cases reported to date, this syndrome of thrombocytopenia (low platelet count) and venous thrombosis (blood clot) appears to be triggered by receipt of the first dose of the (AstraZeneca) ChAdOx1 nCoV-19 vaccine. Although there have been a few reports of patients with symptoms consistent with this clinical syndrome after the receipt of other vaccines against SARS-CoV-2, none have yet been confirmed to fulfill the diagnostic criteria,” they added.

But if vaccination can cause the situation, it could be necessary to acknowledge that and deal with it appropriately — as a result of the same old remedy for blood clots just isn’t really helpful for VITT.

Patients needs to be given anti-clotting medication, however not heparin, and infusions of a blood product referred to as intravenous immunoglobulin might change the depleted platelets.

Some European nations have restricted who ought to get AstraZeneca’s vaccine. For instance. Belgium limits its use in folks below age 55. Other nations have paused its use. CDC’s vaccine advisers have been requested to think about whether or not comparable restrictions is perhaps acceptable for Johnson & Johnson’s vaccine, though solely a handful of instances have been reported in the US.

While blood clots in the mind have acquired essentially the most consideration, sufferers have additionally had clots in different giant veins and arteries.

These blood clots in the mind — referred to as cerebral venous sinus thromboses or CVST — are dramatic on their very own, however the clots could also be forming elsewhere, additionally.

Doctors are being suggested to run assessments if folks develop blood clots after having been vaccinated not too long ago towards coronavirus, and to not use heparin to deal with the clots till VITT has been dominated out.

ASH printed steerage saying regular post-vaccination malaise, headache and fever usually are not of concern.

“Patients with severe, recurrent, or persistent symptoms, particularly intense headache, abdominal pain, nausea and vomiting, vision changes, shortness of breath, and/or leg pain and swelling, either persisting or beginning four to 20 days following vaccination should be evaluated urgently by a medical provider and consideration given to underlying VITT,” ASH says in the brand new steerage.

“While current information links VITT to AstraZeneca and Johnson & Johnson vaccines, patients with suggestive timing and symptoms following any COVID-19 vaccine should be evaluated for VITT.”

CDC’s Advisory Committee on Immunization Practices has scheduled a gathering for April 23 to take up the query once more after declining to decide Wednesday. One committee member advised CNN extra information is required.

“We need to know what the size of the problem is,” mentioned Dr. Kevin Ault, professor and division director with the University of Kansas Medical Center. “So we’re going to shake the trees in the databases that the CDC has and we also need to know what the denominator is — is it just young women or the whole population that’s been vaccinated?”

CDC needs to know if there may be something particular which may put folks at greater threat of creating blood clots after vaccination.

“There are still a fair number of people in the United States who have been vaccinated in the last two weeks,” Ault mentioned. “We’ve seen these reactions within two weeks, so it doesn’t sound like a very long time, but we’ll have a fair amount of data in just those nine or ten days.”

In a letter to the New England Journal of Medicine, scientists at Janssen, the vaccine arm of Johnson & Johnson, say there is not sufficient proof to indicate the corporate’s Covid-19 vaccine causes the blood clots and they’re “working closely with experts and regulators to assess the data, and we support the open communication of this information to health care professionals and the public.”

“At this time,” they write, “evidence is insufficient to establish a causal relationship between these events and the Ad26.COV2.S vaccine.”

Vaccines made by Moderna and Pfizer/BioNTech use a distinct know-how that sends genetic materials into the physique wrapped in lipids, and so they haven’t been linked with blood clots.