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Are triple-vaccinated people more likely to be infected by the Omicron variant than the unvaccinated?

No. But that is the message television viewers in France apparently got from an interview with Dr. Martin Blachier.

You may not have heard of Blachier, but in France TV viewers are as familiar with his face as we are here with Dr. Fauci’s. And he caused the COVID pot to boil over a couple of days ago when he supposedly claimed that data from Denmark show that people who are triple vaccinated are more likely to be infected with the Omicron variant than the unvaccinated. Let’s take a look.

Blachier is somewhat of an enigma. He graduated from medical school but has never practiced medicine. He also has degrees in epidemiology as well as in statistics which led to his establishing a company that provides data to various commercial enterprises including some pharmaceutical companies. He rose to fame with his strong criticism of Dr. Didier Raoult who had become a French icon with his "discovery" that hydroxychloroquine is the cure for COVID, which of course is not the case. Blachier, to his credit, pointed out the weakness of Raoult's "evidence" and aroused anger because he had criticized Raoult who the French media had elevated to a demi-god status.

Blachier has waffled on mask mandates, originally supporting them, then opposing them. He is a supporter of vaccination but will not vaccinate his children. He is not devoid of conflict of interest since some of his clients, Gilead for example, produces drugs (remdesivir) to treat COVID and Blachier has promoted this drug beyond what the evidence shows.

As far as his remarks about the Danish data go, he is said to have implied that triple-vaccinated people are more likely to be infected with Omicron than the unvaccinated. He has clarified his remarks and says what he meant is that if you are triple vaccinated and still get infected, then there is a greater chance that the infection will be due to Omicron than Delta. If you are unvaccinated, then the Delta variant is more likely to be the cause of an infection. He correctly states that this does not mean you are more likely to be infected if you are triple vaccinated.

The data that prompted the whole discussion shows 8% Omicron infections among the triple vaccinated and 1.2% among unvaccinated. This actually makes sense. Since the vaccine works much better against the Delta variant than against Omicron, you would expect that whatever infections arise among the triple vaccinated are more likely to be Omicron because they are better protected against Delta than against Omicron.

The important question, however, is not the relative Omicron/Delta distribution among the vaccinated versus the unvaccinated, but the rate of infection among the triple vaccinated versus the unvaccinated no matter whether the infection is due to Omicron or Delta. The Danish data show that infections are about four times more prevalent among the unvaccinated.

It isn't quite clear whether Blachier originally did say that triple-vaccinated people are more at risk for infection by Omicron, or his statement was misinterpreted by the media, which would not be surprising. In any case, he does not seem to be one of the worst players in the sad game in which we are engaged.

While much about the Omicron variant remains unknown, it is clear that it is spreading misery with unprecedented speed. Researchers at the University of Hong Kong have some preliminary evidence for why this is happening. In tissue isolated from human bronchial tubes, they showed that the Omicron variant multiplies about 70 times faster than the Delta variant which means that more virus is expelled with each breath, which in turn means that anyone close-by is exposed to more viral particles. It seems that mutations in the spike protein of the Omicron variant lead to a better fit into the ACE2 receptor on the surface of cells affording easier entry into cells and more rapid multiplication.

It should be pointed out, though, that the experiment used isolated tissue infected with the virus in a Petri dish which may not necessarily be representative of what happens in the body since isolated tissue does not have the same immune response to invading microbes. Also, the effects were monitored only over a 48 hour period so whether the rate of multiplication stays the same over a longer time frame is not known. What is needed is a measurement of viral loads inside people’s respiratory tracts as has been done with Delta. In that case, there are 1000 times more viral particles in the respiratory tract than with the original virus. Chances are that this number is even larger with the Omicron variant.

Interestingly, the Hong Kong experiment also tested tissue isolated from the lungs, and in this case, Omicron was less efficient at infecting cells than the original SARS-CoV-2 virus or the Delta variant which may explain why once infected, the Omicron variant may cause less severe symptoms. At this point, the best protective measures are still masking, distancing and of course, vaccination. Unfortunately, the Omicron variant has dimmed the light at the end of the tunnel somewhat.


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