The bad news coming out of South Africa Friday is that researchers are now able to say that Omicron appears to be quickly taking over as a dominant strain, and it appears to have an Rt that's 2.5 higher than the Delta variant.
The true Rt or R0 (reproductive number) metric of the new variant, which gauges how many new infections stem from each infection, is likely still a work in progress. But the original strain of COVID was said to have an Rt of between 2.0 and 3.0, and Delta has been said to have an Rt anywhere between 5.0 and 7.0. Does that mean the Omicron variant's Rt is between 12.5 and 17.5? If so, that would be insane.
But as the New York Times reports, that is what researchers in South Africa are saying. And in these early days, the rate of new daily infections in the country appears to bolster that, with new infections up 35% in one day, and the test-positivity rate rising from 16.5% to 22.4% in just one day on Thursday. The positivity rate was at 2% just two weeks prior.
Juliet Pulliam, an epidemiologist at the University of Stellenbosch in South Africa, tells the Times, "It is actually really striking how quickly [Omicron] seems to have taken over." Pulliam and her team also now estimate that Omicron is 2.4 times more likely to cause a reinfection in patients previously infected with another variant.
Researchers, many of whom have been sounding the alarms about Omicron in recent days, say that the variant's many mutations make it more successful at infecting people through some combination of evading immune defenses and being highly transmissible, but it's still not clear which it is doing in greater amounts.
As one mathematical modeler, Carl Pearson, tells the Times, "We’re not sure what that mixture is. It’s possible that it might even be less transmissible than Delta." But that still doesn't seem very reassuring given all of the above.
It also remains unknown whether this variant causes any more or less severe illness in those who contract it, especially if they are unvaccinated.
Cases of Omicron are reportedly doubling every three days in South Africa's densely populated Gauteng province, which is home to both Johannesburg and Pretoria. South Africa's overall vaccination rate is just 25%, but that rate is a bit higher in Gauteng, with 30% of residents fully vaccinated, and 36.5% have had at least one shot.
As the Daily Maverick reports, South African officials are especially worried about many residents of Gauteng province traveling over the holidays in December and unwittingly spawning more of a nationwide wave of infection than is already occurring.
Federal officials in the U.S. warn that community spread of the Omicron variant is likely already occurring, and we may begin seeing upticks in case counts soon. As of Friday, the variant has been detected in samples in six states: New York, Minnesota, Nebraska, Colorado, California, and Hawaii. At least a couple of those cases were not individuals who had traveled abroad.
On the good news side of COVID this week, an FDA advisory panel has recommended emergency-use authorization for Merck's COVID antiviral, Molnupiravir, and the FDA will likely take that recommendation soon. The Examiner reports that local experts believe Molnupiravir will be hitting Bay Area pharmacies by the new year, but it is only being recommended for patients at risk of serious COVID complications.
Pfizer's treatment pill, Paxlovid, is also coming up for review.
Both pills have been shown to be effective in trials at preventing severe disease and death in people infected with COVID, with Paxlovid showing 89% effectiveness.
As we learned in November, the Biden Administration has already committed to purchasing $5 billion worth of the pills being developed by Pfizer — enough to treat 10 million infected patients — as well as 3.1 million courses of treatment of the Merck pill. Manufacturing for these drugs is expected to ramp up, and the pills won't necessarily be widely available until the middle of next year.
Top image: AMSTERDAM, NETHERLANDS - DECEMBER 02: A health worker tests passengers for the Coronavirus at Amsterdam Schiphol airport on December 2, 2021 in Amsterdam, Netherlands. The Netherlands and other nations worldwide temporarily banned most travellers from South Africa after a new variant of Covid-19 named Omicron was discovered. Omicron has sparked worries around the world that it could resist vaccinations and prolong the nearly two-year Covid-19 pandemic. (Photo by Pierre Crom/Getty Images)