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Harry Rakowski: Simple blood test detects clotting from AstraZeneca vaccine early enough to treat

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Vaccines offer the surest hope of getting out of this pandemic and returning to normal, but there are still high rates of vaccine hesitancy in this country. In the coming days, the National Post’s Road Map to Immunity series will take an in-depth look at the issues surrounding vaccines and why some people are still reluctant to take them.

The federal government’s mixed messaging on vaccines has left many Canadians wondering: which one should I take?

Recent statements from the vice-chair of the National Advisory Committee on Immunization (NACI), Dr. Shelley Deeks — who suggested that the mRNA vaccines are preferred and that some Canadians may want to wait for them — has created an uproar because it is both confusing and anxiety-provoking.

It is particularly ironic when the message has to be clarified by a prime minister who is an expert not in medicine, but in obfuscating the truth about charity scandals and military misconduct. Health Minister Patty Hajdu further muddled the message when she pivoted from the advice that Canadians should take the first vaccine that’s made available to them and said they should ask their doctors what is best.

In reality, we have four highly effective COVID-19 vaccines that have been approved by Health Canada. There is excellent trial and real-world data on their efficacy, along with extensive safety data. But we are short on supply.

Our initial goal was to protect the most vulnerable, in order to reduce hospitalizations and death. The surging third wave of infections and its effect on ICU capacity has strained the health-care systems in some provinces and amplified the need to get as many first doses into the arms of as many people as possible.

The truth is that there are no bad vaccines — period. The AstraZeneca (AZ) and Johnson & Johnson (J&J) shots are similar viral vector vaccines and thus it is not surprising that they have similar efficacy and risks. The AZ vaccine was the most common one used in the United Kingdom and was highly effective in reducing hospitalizations and deaths. Young people in the U.K. are now dancing in pubs, while we are still huddled in our homes.

The heightened anxiety and the misplaced belief that there are good and bad vaccines stems from the fact that both viral vector vaccines have been found to cause blood clots in some people. But it is extremely rare, occurring in up to one in 100,000 people. This complication has already led to Ontario limiting AZ use to second injections (Alberta has done the same, but the province cited a shortage of supply).

Yet the blood-clotting complication has a unique signature, namely an allergic reaction similar to that seen with the anti-clotting drug heparin. It’s caused when blood platelets responsible for normal blood clotting are damaged by antibodies that are formed against them. The remaining platelets are also induced to release blood-clotting factors that cause clotting events. The syndrome is called vaccine-induced thrombotic thrombocytopenia (VITT).

This complication, while not predictable in any given person, does have a unique signature that is different from much more common blood-clotting complications, such as those seen in phlebitis or resulting from birth-control pills.

What has not been discussed is that VITT can be easily discovered after receiving a viral vector vaccine by measuring blood platelet levels. If blood platelets levels are normal seven days after getting an AZ or J&J shot, VITT is unlikely to occur. If platelets are low, confirmatory tests for VITT can easily be done and an antidote given before serious complications arise.

So why is this information not being made public and discussed? Is it because health authorities are concerned about swamping labs with blood tests, and because physicians may be worried about dealing with the anxiety caused by detecting minor changes that will not prove harmful? We need a thoughtful dialogue about this.

I have offered this simple blood platelet test to people who are afraid of the AZ vaccine. It has influenced their decision to proceed, as they have been comforted by the fact that the complication could likely be detected early enough to prevent disabling complications or death.

What is missing in the Canadian government’s advice on vaccines is unified, intelligent guidance from trusted health-care advisors. In the United States, Dr. Anthony Fauci has the experience and gravitas to be believed by most sensible Americans. Dr. Rochelle Walensky, the head of the Centres for Disease Control, is a highly respected scholar, Harvard professor and infectious disease expert. Their analysis is thoughtful, honest and when facts change, they change their guidance in a believable way and communicate it clearly and effectively with a single voice.

We need similar quality of leadership in Canada and are not getting it from NACI or the Public Health Agency of Canada. The AZ and J&J vaccines are highly effective and should be recognized as such.

It’s true that some vaccines are more suitable for particular groups, but that doesn’t make any of them inferior. If you want a vaccine passport with only one shot, then the J&J vaccine is the only current choice. If you are older and need greater protection from infection and variants of concern because of a lower age-related antibody response, then the Pfizer or Moderna mRNA vaccines may be best.

If you are at higher risk because you live in a hot spot, or have personal risk factors that make it more likely that you will experience a bad outcome if you’re infected, then you should take the first vaccine that’s made available to you. If you’re worried about taking the AZ or J&J shots, a simple blood test may make you less hesitant.

Government and medical professionals should be clear about the steps that can be taken to reduce bad outcomes due to VITT, so that important vaccines will not be rejected as inferior. This should include a dialogue on whether platelet count blood tests should be offered to hesitant people or to those who may be at higher risk of this unique and rare complication.

Canadians are intelligent enough to understand issues explained in clear language by knowledgeable and trusted people. Emily Dickinson said, “Truth is so rare it is delightful to tell it.” We don’t get much of it from our politicians. Let’s hope we can get it from health-care advisors who can learn from their mistakes.

National Post

Dr. Harry Rakowski is an academic Toronto cardiologist and commentator.

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