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Changing vaccine doses risky

Vaccination of individuals with dead or modified versions of a virus is a very old technique, pre-dating the discovery by Edward Jenner that cowpox could protect against smallpox.
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Vaccination of individuals with dead or modified versions of a virus is a very old technique, pre-dating the discovery by Edward Jenner that cowpox could protect against smallpox. Variations of techniques using variolation appear to date back a thousand years.

And there is also no doubt vaccination against smallpox effectively eradicated the disease by 1980. Other vaccines have either eliminated or significantly reduced the incidence of the mumps, measles and rubella, among other diseases.

However, some of the early vaccine trials were carried out using unethical methods, involving prisoners or indigent people. Two hundred years ago, with little understanding of germs or biochemistry, doctors didn’t really have a good understanding of what they were doing.

Since then, medical science has undergone major transformations. We now understand the biochemistry and microbiology involved in viruses and the diseases they produce. Perhaps more to the point, we can now engineer vaccines relatively quickly.

Our lives are much better – healthier, stronger, longer – because of vaccines. No question about it. Or, at least, most people likely see it that way.

But a few years ago, Dr. Andrew Wakefield published an article claiming a link between the MMR vaccine and autism. There is no link and his publication has been thoroughly discredited by multiple studies paid for with public funds.

Unfortunately, though, his work fed an already existing movement of people who distrust vaccines and large pharmaceutical companies leading to a rejection of vaccines and the science behind them. I am not trying to defend large pharma here. But the distrust of vaccines is unwarranted at multiple levels.

We are now facing a pandemic caused by a virus for which we have several vaccines. Some are new technology employing strands of mRNA, which will prompt an immune response. Some are more traditional vaccines employing tried and true technology. Over the next year, a multitude of vaccines will eventually become available.

If the minister of procurement is to be believed, by the end of March, we will have two million doses available every week, which will give us the capacity to immunize a million people. Add in the doses already administered and we should achieve herd immunity before September. Canada should have the capacity to immunize everyone in the country before the end of the year.

However, we now have jurisdictions substituting their own dosing regimens for those prescribed by the manufacturers. They are meddling with the medicine. The political argument is “better to have the whole population have half immunity than half the population have whole immunity.”

That might be convincing, if the disease affected everyone in our population in the same way. But we are not. As it stands, in Canada, about 97 per cent of those infected with COVID-19 survive – albeit with long-term consequences in many cases. The elderly and people with comorbidities dominate the three per cent who do not recover.

The BC government is taking the better approach, saying: “perhaps it would be better to have those most at risk of dying from the disease develop full immunity before we vaccinate those less susceptible.” 

Of course, this means some people will be waiting in line for a while and some of those waiting in line will get sick.

Politics aside, there is a great deal of concern and debate among virologists and epidemiologists about the efficacy of changing dosing routines.

We know the virus is mutating. Many strains of COVID-19 are already circulating. A recent new Brazil strain, for example, has been branded as a super strain amid fears it may have mutated spike proteins, which would not be recognized by antibodies rendering it invisible to the response generated by the new vaccines.

As a consequence, despite a herculean effort to develop and manufacture the vaccines as soon as possible, they could be rendered ineffectual by mutations in the virus. No one is quite sure yet.

One of the possible outcomes of delaying the second dose of the vaccine would be to drive up the mutation rate of the virus. The first dose would only produce a minor immune response, which would eliminate some of the viruses. Delaying the second dose would then allow the remaining viruses to mutate and evade the antibodies generated.

As a consequence, despite being vaccinated, people would still get the disease, feeding the political and social rhetoric claiming vaccines don’t work and further fueling vaccine hesitancy while stoking the claims of those who think COVID-19 is a giant hoax. In the meantime, the pandemic would keep rolling along.

In the end, our political leaders need to be guided by science. 

And by the best science available. 

Not by what appears to be popular. 

And not by what sounds good. 

In the meantime, practicing social distancing and wearing a mask is the best we can do.