The Coronavirus vaccines, virus mutations and where are we now?

The miraculous and incredibly expedited fashion in which scientists were able to produce vaccines that appear to be singularly effective against the coronavirus at least in terms of reducing hospitalizations and those who develop significant illness has resulted in these being distributed in a number of countries around the world and now in Australia it’s our turn to benefit from what may be a planetary redeeming godsend or is it?  Health authorities have advised that the only way to escape the tentacles of this life crushing pandemic is for as many of us to be vaccinated as possible, making it extremely difficult for any of us to turn our backs on this seemingly life-saving technology.  Just to reflect on the overwhelming numbers of those who have succumbed to this disease and those who continue to suffer at the hands of a malicious microbe that has eroded the very fabric of our daily lives makes the promise of terminating its stranglehold on our existence and a return to some form of normalcy seductively irresistible.  The possible side effects of vaccination which have yet to be clearly determined pall into insignificance compared with how pernicious this virus can be.  For many experts this makes vaccination a no brainer.  They would assert that it’s our only way to awake from this nightmare.  They would reprimand that ignoring the lifeline provided by the genius of scientists is tantamount to a crime against humanity.

In a recent online forum Professor William Hanage, associate professor of epidemiology at Harvard’s T.H Chan School of Public Health, explained how effective the current vaccines, including the Pfizer and AstraZeneca vaccines, are at providing us with adequate protection against the coronavirus, especially the mutant strains, which appear to be more virulent than the original strain of this infestation.  The concern about these mutants is not only that they are more transmissible but also that they are more lethal causing more severe disease and with that increased fatalities.   

 What the AstraZeneca vaccine does is inject the genetic code of the virus housed in what’s called a viral vector or delivery system which in this case is an adenovirus, that also causes colds and flu.  But rather than trigger infection the adenovirus simply transports the gene of the coronavirus into our cells where it starts to manufacture spike proteins or that portion of the virus that switches on our immune cells primed to combat this invasion.  Antibodies are made that attach to spike proteins preventing the virus from entering our cells and any cells with spike proteins will also be recognised and destroyed by immune cells.

  Rather than inject the complete viral protein what the Pfizer mRNA vaccine does is expose us to genetic information that primes our cells to manufacture the spike protein that elicits a similar immune response.  More importantly we also make immune memory cells which will immediately mobilise once they encounter that spike protein in the future thereby providing us with instantaneous resistance and protection.

  Clinical trials on both of these vaccines have shown that they are effective at preventing serious disease, although the AstraZeneca did not fare as well as the Pfizer alternative.   The Johnson and Johnson vaccine which operates in a similar fashion to the AstraZeneca vaccine has just become available in the USA.  On the up side it’s a one-shot vaccine but it too might be less effective than the Pfizer option.   The big question is how powerful these vaccines will be once the spike protein mutates exposing the immune system to an enemy that is no longer familiar and therefore not easily recognised and instantly neutered?

 In Professor Hanage’s words he indicated that ‘the amount of neutralizing antibodies which are generated by the mRNA vaccine platform are very, very large. They’re extremely impressive, very immunogenic vaccines. And so even though there appears to be some reduction, it’s not likely that it’s going to be enough to make a major impact upon the efficacy of the vaccines.’

 He further suggested that ‘while the Astrazeneca vaccine is less good it does seem to be very good, indeed, at preventing severe disease.’

 He then went on to caution that circulating in the Amazon is a highly malevolent mutant strain of the virus that surged in May and June of last year and then even more so recently in January leading to debilitating disease and a significant increase in death rates.  While Professor Hanage appears to be confident that existing vaccines will outsmart this strain he guardedly advises that this remains to be tested.

  While the vaccines might prevent crippling disease whether they can provide a true firewall against these mutant strains and the emergence of new mutants is an evolving story.  What’s equally contentious and critically important is their ability to prevent transmission of the disease because if this is aborted the virus will not be able to sustain itself.

 Once again in Professor Hanage’s words.  ‘There is some evidence that the mRNA vaccines do prevent transmission, some of it, a little bit– And there’s also, the quantity of neutralizing antibodies that are produced, seem to be consistent. It seems implausible that they would not be any effect upon transmission. How large the effect is, it’s not entirely clear.   But I think it’s reasonable to think it’s pretty high.  The issue with the AstraZeneca vaccine is it may be somewhat less and that means that, even while I think that it’s probably a pretty good vaccine, certainly in terms of preventing disease, it’s a little more unclear as to what it’s been going to be doing in terms of transmission.’

 Despite this level of uncertainty Israel has motored ahead of the rest of the world by rolling out a vaccine passport which provides a green light for entry into cinemas, hotels, swimming pools, places of worship and major events.  Already just about half of their population has been vaccinated.  Will this be used as a template by other nations and will it work both as an incentive and to eliminate the virus?  We’ll see.

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