Waiting On Omicron With Tenterhooks of Apprehension

"For the unvaccinated, mild COVID could train the immune system, much like vaccines. For the vaccinated it would be like a natural booster."

"[Should it somehow turn out that the Omicron variant produces only mild disease]; That would mean let it run. Let it run its course and reach the world."

"Maybe it causes half the amount of hospitalization and deaths. [But if there are far more infections], that's still a lot of hospitalizations and deaths."

"It could be in a population that was so isolated that Omicron evolved there and it never got out until now. It's possible that Omicron has been hiding out for most of 2021 inside somebody. That would suggest that all these changes in the spike that we're seeing actually weren't selected to help transmit from person to person. They were selected to survive and propagate within that person's body."

"But we really have zero idea. At this point I give it about a 50-50 chance of being more or less severe. That's how unsure science is at the moment."

"[If it can spread much more easily through the air], and you need even smaller particles to get infected because it's so good at getting inside our body, that is a game changer. That's my nightmare." 

Sarah Otto, evolutionary biologist, University of British Columbia

"For viruses to evolve to become less severe there needs to be 'selective pressure'. "They [viruses] don't 'care' about how sick they make people, as long as they can spread."

"[With SARS-CoV-2 the virus can spread quite efficiently, even if people don't yet show symptoms, or fail to altogether, meaning] it's not clear that there's much pressure on the virus to cause less severe illness."

Matthew Miller, associate professor of infectious diseases and immunology, McMaster University, Hamilton

Medics at an infectious-disease unit in South Africa, where a new strain of COVID is spreading quickly.  Credit: Alet Pretorius/Gallo Images/Getty

New reports have come in from South Africa with some doctors reporting cases they have seen appearing to be mostly mild, with fever, cough, aches and pains, hitting mostly younger adults of university age and healthy people. The reports speak of toddlers in hospital with Omicron, but not the medically fragile. These reports lift the hopes of experts in the field elsewhere, who study them. Doubts exist over whether Omicron is more infectiously spreadable, or can elude a degree of immunity from vaccinations or past infections.

In early stages of an outbreak by viruses new to humans they tend to cause more serious disease leading to a pandemic, attributable party to the fact that there is no pre-existing immunity. When people become very ill very quickly they become less efficient in spreading the virus since their illness keeps them isolated and away from the public. When this happens the virus tends to wear itself out. The SARS-CoV-2 experience has taught science that people can spread the virus efficiently even if they aren't showing symptoms yet.

 

WHO Label	Pango Lineage	Earliest documented samples	Transmissibility	Immune Evasiveness	Vaccine Effectiveness
Alpha	B.1.1.7	United Kingdom	+ + +	— —	√
Beta	B.1.351	South Africa	+	+ + + +	√
Gamma	P.1	Brazil	+ +	+ +	√
Delta	B.1.617.2	India	+ + + +	+ +	√
Lambda	C.37	Peru	+ + + +	+ +	√
Omicron	B.1.1.529	South Africa	+ + + + (?)	+ + + + (?)	?

 

According to studies, 40 to 50 percent of South Africans have been exposed to SARS-CoV-2 in earlier waves with one paper estimating the number of infections to be 7.8-fold higher than recorded cases. A situation of immunity which combined with vaccination could have the effect of providing protection against serious disease, which in part might help explain why symptoms of the Omicron infections appear mild. Scientists tend to to be fixated on the number of mutations on the Omicron spike protein.

It is that spike on the surface of the SARS-CoV-2 virus used by it to fix itself onto body cells when infection occurs, enabling the virus to replicate once it reaches the organs. "We've seen some of these three mutations [which enable the spike to better bind to cells] in different variants of concern [but none have all three. When my colleagues saw that they were like, 'Uh, oh'," said Dr. Otto. Cases of Omicron have now been confirmed in Canada, the U.S., Belgium, the Netherlands, France, Germany, Portugal, Italy and the United Kingdom. Like the original, it has lost no time in international travel.

There is a theory that the new variant might have been living inside one or two immunocompromised people for whom clearing the virus was difficult. In such hosts the virus could reproduce to high loads -- alternately linger for a greater period of time in people with immune systems weakened by malnutrition, unclean drinking water, untreated HIV or other conditions, according to Professor Miller. The greater the length of time the virus remains in situ, the more opportunities it has to acquire mutations.

On the other hand, according to Dr.Otto, though Omicron possesses a range of mutations in the spike protein "there's still a lot of spike that's not changed, and our immune reactions should recognize other parts well if we've been vaccinated. But it will spread like wildfire among the unvaccinated". According to the head of Moderna a "material drop" in vaccine efficacy is expected. Yet Dr.Otto is optimistic that a high vaccination rate means "we've got a base of immunity, and it's not like [Omicron] has changed at hundreds of sites in the spike. It's just changed at 30". 

Tellingly, in Tshwane, South Africa where Omicron was first identified, 87 percent of hospital admissions took place among the unvaccinated. Dr.Otto still finds it troubling that a fully vaccinated traveler who had arrived in Hong Kong from Vancouver contracted the variant virus from another traveler from South Africa staying across the hall in the same airport quarantine hotel. Translated into transmission terms it may mean that Omicron is able to transmit through smaller particles in the air, relating to more longer-distance aerosol transmission.

A man receives a dose of a COVID-19 vaccine in Soweto, Johannesburg, South Africa, on Monday. The omicron variant, first identified in South Africa, has now spread to at least a dozen other countries. Denis Farrell/AP