Omicron, Projections and Mysteries

 The University of Washington prediction has just come out:

140M new COVID infections to US in the next two months, model predicts

They found the U.S. may see a total of about 140 million new infections from Jan. 1 to March 1, 2022, peaking in late-January at about 2.8 million new daily infections.

Total infections in the U.S. we forecast are going from about 40% of the U.S. having been infected so far, to having in the next 2 to 3 months, 60% of the U.S. getting infected with omicron.” 

While meta-analyses have suggested previous variants cause about 40% of cases to be asymptomatic, Murray said more than 90% of people infected with omicron may never show symptoms.

Researchers estimate that out of the millions of projected new daily infections, only about 400,000 cases may be reported, as most Americans infected with the virus won’t feel sick and may never get tested. At the peak of last year’s winter surge in January, the country was reporting a little over 250,000 new cases per day.

While infections are expected to skyrocket, the IHME model shows hospitalizations and deaths will be about the same. Researchers found the infection-hospitalization rate of omicron is about 90% to 96% lower than delta, and the infection-fatality rate is about 97% to 99% lower.

“In the past, we roughly thought that COVID was 10 times worse than flu and now we have a variant that is probably at least 10 times less severe,” Murray said. “So, omicron will probably … be less severe than flu but much more transmissible.”

HME researchers don’t expect to update the models before the second week of January as the holidays tend to delay the data, Murray said. But he said the modeling showed the biggest impact on transmission was masking, particularly if 80% of the population wore high-quality masks.

Omicron is now the second most contagious virus on the planet: University Hospitals doctor addresses infection rate

“When we look at the factors surrounding how contagious these viruses can be, the most contagious virus we think of is measles,” explained Dr. Claudia Hoyen, Pediatric Infection Control for UH Rainbow Babies and Children's Hospital. “That has a factor of about 18. This new variant of COVID-19 has a factor of 15, so it is the second most contagious virus on the planet currently.”

There's a giant, mysterious gap in the omicron variant's family tree

Scientists have made remarkable strides in understanding the origin and spread of COVID-19, which is part of what makes the omicron variant so shocking: its origins are perplexing, as it didn't stem from other recent prominent strains like the delta variant. The confusion around its origins creates added hurdles in terms of treating it. 

Besides its incredible virulence, here's why the omicron variant is so scary: Omicron has 30 mutations located near its spike protein, which are the thorn-like protrusions on the SARS-CoV-2 virus' central sphere. 

So how did omicron rack up so many mutations on its spike proteins, without any intermediate steps of evolution through other variants? Scientists have theories about how that happened, though none are comforting. 

 Yet they know for sure that this strain is very different from the original SARS-CoV-2 strain that brought the world to its knees at the beginning of 2020.

So what explains that gap? Where did the omicron variant come from?

One hypothesis is that it developed in an immunocompromised COVID-19 patient. While there is no direct evidence that this happened, scientists do know that viruses can become stronger in the body of a person with a weak immune system, because they circulate for longer — continuing to mutate as they evade the patients' weakened immune system. A virus that circulates for months in the body of an immunocompromised patient might be able to develop superior survival skills by developing defenses against human antibodies.

Haseltine also touched upon the next much-discussed possibility, which is that the omicron variant emerged from a process known as reverse zoonosis — that is, a situation in which a virus that originated in another animals jumps to humans, then back to animals, and then back to humans again. The COVID-19 pandemic originated from the first step of that process (jumping from an animal, probably a bat or a pangolin into humans), and the hypothesis is that the virus somehow jumped from a human to an animal and then back to a human. Indeed, the SARS-CoV-2 virus has proved troubling adept at infecting animals that regularly come into contact with humans.

Bedford also speculated that the omicron variant's mysterious origins could be explained simply by its unknown provenance. There are large sections of the planet where COVID-19 is inadequately monitored, particularly in Southern Africa (where omicron was first detected) so a rampant strain might have evolved several times in one of those regions without being noticed — at least, not until it spread outside that area. 

Haseltine has also advanced the hypothesis that the omicron variant might have arisen because of human intervention. In his Forbes editorial, he suggested that a COVID-19 patient with the Merck drug molnupiravir might have inadvertently incubated the omicron variant. Molnupiravir works by inserting errors into a virus' genetic code, making it harder for the virus to reproduce and therefore easier for the immune system to defeat it. Yet Haseltine claims that if molnupiravir is not administered properly (such as by not being taken over the full five-day period), or even if it is used correctly but everyone involved is just unlucky, it could produce a heavily mutated virus strain.

While omicron explodes around the world, covid cases in Japan keep plummeting and no one knows exactly why

While the new highly transmissible omicron variant has appeared in the country and experts suspect there is already some community spread, the overall transmission rate of the virus and coronavirus-related deaths in Japan have remained low.

“Honestly, we do not know the exact reason behind the sudden drop in covid deaths in Japan,” said Taro Yamamoto, professor of global health at Nagasaki University’s Institute of Tropical Medicine.

Throughout the coronavirus pandemic, Japan has had much lower rates of infection and death than in many Western countries, though there was a severe spike over the summer that overwhelmed hospitals.

In Japan, researchers have also examined factors like weather, cyclical patterns in the spread of the virus, and potential past exposure to mild coronavirus variants that may have led to the low case and death counts. Experts have identified potential genetic characteristics among the Japanese that may have led to a stronger immune system response to the coronavirus, but said there needs to be more research to draw definitive conclusions.

Japan has now vaccinated most of its population and has widespread masking, which may explain the current low numbers. But so does neighboring South Korea, where authorities are rescinding reopening plans because of a spike in infections and record numbers of serious and critical cases. And Japan has barely begun rolling out its booster shots, lagging behind other countries in the region, including South Korea.

“Obviously vaccination, masking and social distancing are surely factors, but those alone cannot explain it, especially when comparing the situation to South Korea,” Yamamoto said. “It is unclear yet whether there is a factor X that exists specific to Japanese or East Asian people, but in determining this we hope it can help us to understand and control the virus.”