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Vaccine varieties and some good news

With vaccine rollout news across Canada changing daily, and with increasing numbers of vaccine varieties coming online, we thought an overview, including what differences there are between each vaccine, might be in order. There is some good news to start off with: last week the federal government announced serious investments (and contracts signed), not just in vaccine development, but in factories and facilities in Quebec and elsewhere that will produce vaccines here in Canada, so we won’t be subject to the laws of other countries in terms of shipments. There are some caveats: the building that will produce one of the latest vaccine types right here in Montreal, Novavax, is still under construction, as the Montreal Gazette reported on Feb. 2, and in fact most of these investments won’t bear fruit until the end of this year at the earliest. Still, it’s definitely a move in the right direction, with more investment attention also being given to COVID-19 treatment possibilities.

It’s important to realize that so far there have been no deaths from COVID-19 suffered by any of the subjects of the many vaccine trials, and significant protection against the virus was established in each and every one. And it’s especially important to realize that a term like “66 per cent effectiveness” doesn’t mean that if you got that shot you’d still have a 33 per cent chance of dying of COVID. Absence of any symptoms at all is the threshold for research “effectiveness,” and so far, subjects have rarely gotten even serious disease, much less death, after their shots. Even if the vaccines confer “only partial” protection from the emerging variants, that too is likely to mean some illness, but “They’re still not dying,” as Dr. Rebecca Wortz of the University of Minnesota School of Public Health has stated. David Leonhardt, in a New York Times column on Feb. 1, said that at this point in the long haul towards mass immunization, “The available vaccine evidence is nearly as positive as it could conceivably be.”

 

There are currently two vaccines for COVID-19 being administered in Canada, with a third expected to be approved this month. PHOTO depositphotos.com

 

As for all those varieties out there or coming online, there are the two well-known front-runners already being administered in Canada, by Pfizer-BioNTech and Moderna, both of which have faltered in terms of shipments but should pick up next month. Both are “mRNA” vaccines; the acronym stands for Messenger Ribonucleic Acid, a kind of “pre-protein” that transmits genetic information to a cell; unlike DNA, a double-stranded molecule, mRNA has only one strand. As explained in Horizon, an online periodical published by the European Commission, in an mRNA vaccine these protein molecules are synthetically produced in a lab to code (fit in) with parts of the coronavirus’s spike protein. Once in the body, these molecules stimulate it to mount an immune response, producing antibodies that will then be present to fight infection when and if the person gets COVID. After delivery, the RNA quickly degrades and disappears. Although this is the first time mRNA vaccines have been deployed on humans, they’ve been studied for decades, as they appear to be safe (no live components) and are “relatively simple to manufacture,” according to a briefing paper by the PHG Foundation, a think tank affiliated with the University of Cambridge.

The disadvantages include unintended immune and allergic reactions, which do happen, but so far have not been more common or severe than expected. Their supposed 90 to 95 percent protection rate (based on two doses, not one) is so far the gold standard. Their storage issues require regular freezing (Moderna) and very cold freezing (Pfizer), which limits distribution. We know now that manufacturing is also a serious problem. Canada has no vaccine factories of its own at this point and production is centred in the European Union, which has moved to block exports. Moderna is produced in Switzerland, which is not an EU member; even so, as recently reported by the CBC, it has still been unable to meet expectations for Canadian deliveries

The next vaccine supposed to be approved here in the next week or so (already in use in Britain and the EU) is Oxford-AstraZeneca, which is similar to the Sputnik V vaccine being used in Russia. It also requires two doses for good efficacy. It uses a “non-replicating viral vector,” in which a synthetically modified version of the virus (i.e., the vector) is what tricks the body into making antibodies that will then be present to fight COVID. These vaccines are more complex to manufacture and have significantly reduced “effectiveness,” about 60 to 70 per cent; but because they don’t require freezing, they could be suitable for younger, healthier populations or those living in poorer or tropical countries, an article in Healthcare IT News points out, and they still seem to work against serious disease. Unfortunately, the same manufacturing issues apply; even though to date Canada hasn’t quite yet approved AstraZeneca, the EU is already threatening to limit exports of that vaccine.

Johnson & Johnson’s whole-DNA vaccine is next in line for approval here. The “instructions,” or the stimulus to produce antibodies, are delivered in synthetically made double-strand DNA, not single-strand RNA. While RNA cannot invade the recipient’s own DNA (it dies out very quickly after injection), whole DNA theoretically could, and it is this vaccine, rather than the Pfizer or Moderna ones, which has inspired that concern. If this happened, it could cause a substance intended to simply protect against COVID to permanently remain active in a recipient’s body, potentially causing auto-immune disease or other long-term problems. This is essentially the assessment from a pubmed.gov article by Medjitna et al., “DNA vaccines: safety aspect assessment and regulation.” Its advantages are that it requires only one dose and regular temperature storage. It doesn’t have the advantage of being made in North America, as one would think; it’s manufactured in the company’s Belgian factory.

Novavax is another vaccine, made in Maryland, just starting phase 3 trials, with a promising 89 per cent efficacy rate; it’s the one slated to be made in Montreal. It is a “subunit protein” vaccine, meaning it takes a part of the COVID virus’s spike protein to stimulate the immune response. As reported by such sources as Healthcare IT News and the CBC, this type of vaccine is well-established for Hepatitis B, pneumococcal pneumonia and shingles, and is considered free of most side effects, therefore suitable for less healthy patients (all vaccines carry some dangers, but they still can be rated). But it’s relatively complex to manufacture and may require boosters and adjuvants (additives like aluminum salts, that increase antigen production and transport, but can also cause reactions). It requires two doses, like most, but can be kept at normal refrigeration temperatures.

The larger lesson we’re learning is that despite the incredible achievement of coming up with so many promising vaccine possibilities in record time, getting them manufactured, transported and then into people’s arms is another challenge altogether. According to the Oxford-based ourworldindata.org, Canada last week was 18th in the world for the rate at which it’s vaccinating its population, behind all the other OECD countries, so currently not doing very well; but with borders largely closed, there’s not much citizens can do but cross our fingers and hope the vaccine we want will be available to us soon. Many of us know Americans who have already had both their doses; but here, even for the Pfizer and Moderna vaccines, much less the others not yet fully deployed, it is likely to be next fall before many people here in the Valley (apart from CHSLD residents, health care workers, and eventually those over 60) will have the chance to get vaccinated.

 

 

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