Omicron 4X as Transmissible, so far Mild, Everyone Needs a Booster

The Covid-19 Omicron variant is 4.2 Times More Transmissible Than Delta, per a Japanese study by Hiroshi Nishiura, a scientist who specializes in infectious disease mathematical modeling. His work, which hasn't yet been peer-reviewed, analyzed genome sequencing data of South Africans in Gauteng province, which originally identified the new variant. He noted that “The omicron variant transmits more, and escapes immunity built naturally and through vaccines more.” This is confirmed by the Covid-19 reproduction rate in South Africa, which rose sharply from 1.0 as of 11/11/21 to 2.0 by 12/1/21. UK Professor Paul Hunter at the University of East Anglia School of Medicine expects Omicron to become the dominant variant within the UK within a month, due to its high transmissibility.

Transmissibility is the bad news. The good news is that none of the many kids in Gauteng province who were diagnosed as having the Omicron variant have died, and they did not fall seriously ill. In most cases they were in the hospital because they had other illnesses. Doctors from the Tshwane District, the metropolitan center of the Omicron wave, have reported that the Covid-19 patients in their hospital have been less likely to need oxygen support, and their time in the hospital has been shorter than it was for patients during the previous Delta wave.

The fact that there were so many incidental patients in the hospital who turned out to have Omicron but were ill for other reasons speaks to both the mild nature of the variant and its transmissibility: people didn't seek medical attention for Omicron because they were unaware they had it. Of the 40 people who have tested positive for Omicron so far in the U.S. nearly all have had mild symptoms; most Omicron cases in Norway, Denmark, the UK, and other countries have also presented with mild symptoms so far. This is also why we wrote of the Omicron Overreaction.

How protective are existing vaccines? Pfizer and BioNTech reported a steep drop in Covid antibodies against Omicron, relative to Delta and earlier varaints, in people double-vaccinated. But a third booster shot increased antibodies 25-fold.

Takeaway: While more studies and data are needed, early consensus is that Omicron is highly transmissible but less virulent than the Delta variant, especially for fully vaccinated individuals. But having a third booster shot is far more protective against Omicron than being only double vaccinated, which may change our idea of what it means to be fully vaccinated. In fact, Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, who presciently predicted back in April 2020 that there could be 800,000 deaths in the U.S. from COVID-19 within the next 18 months (currently 793,000 Americans have died of COVID-19) has said that in light of more recent data, Pfizer and Moderna should have been three dose regimes all along: “…we do need that third dose–and not as a luxury dose, but the thrid dose of a three-dose prime series…the whole world should have access to three doses of an mRNA Covid vaccine.” Note that Osterholm was presumably speaking only of adults and older teens, as booster shots haven't been approved yet for children under 16.

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