Q) How is Omicron variant from the other COVID-19 variants?
A) At the risk of any information shared here becoming badly outdated two days later, Omicron seems to be unique from the other variants in a number of different ways.
This has already dramatically reshaped our vaccine strategy with the rescinding of the plan to cancel the need for a vaccine passport come January and the escalation in the availability of booster shots to younger and younger age groups. It seems likely that further changes are on the way, perhaps in the very near future.
Its uniqueness comes down to the sheer number of mutations this particular variant has. All variants, by their very definition, exist because of mutations in their genetic code from that of the original virus. These mutations sometimes allow the new version of the virus to thrive whereas others weaken the virus to the point that it is quickly defeated by our immune systems or by other versions of the virus as they compete for human hosts.
The Omicron variant has an extremely large number of changes (another word for mutations in this context), up to 32 in its spike protein alone. This is important because when our host defences (i.e. our immune system) target the virus they use pre-existing antibodies that have been created either by vaccines or from previous infections. These antibodies essentially “fit” onto the spike protein of the virus as they encounter it while circulating in our bloodstream together. This ”fit” results in a cascade of events that are aimed at destroying the virus and preventing us from becoming sick.
With each mutation on the spike protein however, it becomes more difficult for our antibodies to recognize the variant as an enemy and to trigger our protective immune response. Thus, even those of us with some degree of protection (once again, from either being previously vaccinated or infected) could be more susceptible to this new variant than we would be to previous versions.
To date, the data (the vast majority of which comes from South Africa, the first country to identify the Omicron variant) seems to support this theory. The risk of reinfections (the term used for becoming sick with the same virus more than once) appears to be far higher with Omicron than was seen with Delta or any earlier versions. As well, vaccine efficacy against Omicron appears to be substantially lower than has been reported with all previous variants.
Two doses of the Pfizer/BioNTech version provides just 33% protection against becoming infected down from about 87% vs Delta. Booster doses restore protection to about 48%. But the vaccines continue to score very highly on the number that matters most; their ability to prevent you from becoming seriously ill.
For those people with waned immunity (i.e. their second dose of the vaccine was many months ago), the level of protection against hospitalization is at 67%. Compare that to people who more recently received a 2nd dose, it is estimated to be at 86% and it rose all the way to 91% in those who have now received a 3rd dose booster.
Another way the mutations appear to have impacted Omicron is that it has made it far more infectious than any other variant we have seen. We are seeing the evidence of this on a day-by-day basis. As of October 13th, 31% of Ontario’s infections have been identified as the Omicron variety and the number of cases appears to be doubling every three days, which mimics both the UK and South African experiences. Delta has an estimated reproduction number (this number reflects the number of new people one COVID positive person is likely to infect) of 1.09 in Ontario, Omicron’s is 4.01. That number is truly scary and should serve as the impetus for us to remain cautious and vigilant during this holiday season.
Remember, you can purchase do it yourself rapid COVID tests at most pharmacies for under $20 and you get the results in 15 minutes. Though it is not as accurate as a PCR test, it may put your mind at ease before setting off to visit Grandma this holiday season.
However not all the news about Omicron is of the doom and gloom variety. If there is a silver lining, it might be that this variant may be less virulent in nature. Data from South Africa seems to indicate that Omicron causes a milder form of the disease.
Of those requiring hospitalization, only about 30% have been seriously ill which is less than half the rate seen in previous waves. The average stays in hospital have also been shorter, about 2.8 days as compared to eight. Lastly, just 3% of those hospitalized have died, a number that pales in comparison the 20% seen in South Africa’s earlier outbreaks.
Now, before we start doing handstands about this, there are a few facts we need to consider before we assume our experience with Omicron will resemble South Africa’s. Their population has too massive advantages over ours that may have led to their apparent lack of severity. First, far more of their population has been previously infected by COVID than ours and that may confer a benefit in surviving an infection that not many of us on this side of the ocean have.
Secondly, they are a much younger population meaning their natural immunity overall is going to be stronger. Let us hope the same holds true here in Canada. If Omicron does prove to be less severe here, its impact on our health care system could still prove critical just due to the sheer volume of people becoming infected.
In time, many experts expect COVID to transition to an endemic type of disease such as the flu, or even better, the common cold. It is the evolutionary nature of viruses that the form that eventually becomes the most dominant is the one which spreads extremely easily by being very contagious. It is very often relatively mild so that its hosts are not feeling overly sick so that they stay home and thus continue to go out in public and spread it further. That pretty much exemplifies the nature of the common cold we are so familiar with. For more information about this or any other health related questions, contact your pharmacist.