Health Canada has just added a new warning to the Astra-Zeneca (AZ) COVID-19 vaccine. This vaccine uses a modified cold virus, an adenovirus, to carry information into your cells on how to make copies of the spike protein that normally is found on the surface of the SARS-CoV-2 coronavirus that causes COVID-19.

The spike protein is released into the circulation where the immune system realizes it doesn’t belong and is activated. If you now encounter the virus, your body will be able to respond in time to keep you from getting very sick. Since the AZ vaccine was approved, some rare but important concerns have appeared.

Originally it was called “vaccine-induced prothrombotic immune thrombocytopenia” or VIPIT, but now its official name is “vaccine induced immune thrombotic thrombocytopenia” (VITT). Simply put, people have developed clots blocking off blood vessels and the number of platelets in their circulation dropped, putting them at risk for bleeding after being vaccinated with the AZ COVID-19 vaccine. Though rare, it has caused a dramatic change in how we use the AZ vaccine.

More recently the European Medicines Agency (EMA) that regulates and approves medications for Europe has reported six cases of “capillary leak syndrome”. This very rare disease was first described in the 1960s. Previously, there had been a total of approximately 500 cases known worldwide. It causes swelling of the hands and feet because the lining of the smallest blood vessels in our bodies, the capillaries, leak.

The vaccine-triggered form of this disease has affected mainly women within four days of being vaccinated. The danger is that when the liquid part of our blood, the plasma, leaks out of the blood vessels, it takes with it albumen and other proteins so their levels fall in the circulation where they’re needed. Furthermore, the blood becomes too concentrated and the blood pressure can drop.

There may have been one additional case in Canada so far. Three of the reported cases were in people who were already known to have this syndrome. So the vaccine triggered something they already had rather than creating the disease. Rare, however, doesn’t mean it’s not important for doctors and patients to be aware. This is why the EMA and Health Canada have notified health care providers and the public.

This has not been reported with the 2 mRNA vaccines from Pfizer and Moderna. It’s worth emphasizing how well our vaccine monitoring system is working. To figure out that there were six cases out of the approximately 78 million doses of this vaccine used, gives you a sense of how carefully things are being followed.

About those grey hairs

A study in eLife looked at hair in a new way. The scientists were able to analyse single hairs in much greater detail than previously which enabled them to show that stress can cause hair to go white. Furthermore, it was reversible with relaxation and stress relief under some circumstances. Bottom line, more proof that stress can affect your health but also further evidence that you can do something about it.

Dr. Mitch Shulman is an Associate Professor in the Department of Emergency Medicine at McGill Medical School as well as an Attending Physician in the Emergency Department of the McGill University Health Centre. He’s also the CJAD AM 800 Medical Consultant.

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