An epidemiologist has claimed if Omicron-specific vaccines don't arrive soon, it might pay to let the variant spread - possibly giving people protection against more dangerous future variants, particularly the unvaccinated.
The call comes as scientists begin to figure out why Omicron doesn't appear to be as virulent as Delta and other earlier strains of the SARS-CoV-2 virus which causes COVID-19, leading some to suggest an end to the pandemic could be in sight.
"If everyone is going to be exposed to COVID-19 at some point (which seems likely), then it would make sense for those who refuse to get vaccinated to take their chances with Omicron; the next variant may be more virulent again," Australia-based Kiwi epidemiologist Tony Blakely of the University of Melbourne wrote in a piece for The Age.
While pharmaceutical companies work on vaccines specific to Omicron, the original formulas - designed to fight the original strain that emerged from China in 2019 - still offer strong protection against severe illness and death.
But the original two-course regime is ineffective at preventing infection with Omicron, leading to skyrocketing infection rates around the world wherever it's shown up - even Portugal, with 87 percent total vaccination coverage (compared to New Zealand's 77 percent), is suffering its worst outbreak of the entire pandemic to date.
Omicron's infectiousness has prompted many countries - including New Zealand - to bring forward their booster campaigns.
Virulence
Luckily, it seems Omicron isn't quite as virulent as Delta. While charts showing infection numbers have gone almost vertical, in many places hospitalisations and deaths are staying relatively flat, or at least rising more slowly than in previous waves. It's been unclear whether this was because Omicron was infecting a lot of people with some immunity, whether from vaccines or prior infection, or it truly is less dangerous.
While still able to kill, new studies have found it's likely Omicron is genuinely less virulent. Real-world data from the UK this week show Omicron patients are only about a third as likely to end up in hospital than those with Delta.
And lab studies on the virus itself suggest it's because unlike other strains, Omicron doesn't really get into the lungs and other vital organs, sticking to the upper airways.
Researchers from the US and Japan experimenting on hamsters and mice found Omicron was far less likely to damage their lungs and kill them than other variants. Notably, Syrian hamsters - a species that fell seriously ill when exposed to all former strains of the virus - fared well against Omicron.
"This was surprising, since every other variant has robustly infected these hamsters," Washington University virologist Michael Diamond told the New York Times.
While there was just as much viral material in the hamsters' noses as in previous strains, Omicron resulted in 90 percent fewer infected cells in the lungs.
Looking at infected human lungs, researchers in Hong Kong found similar results - Omicron grew quickly in the upper airways, but struggled further down. It's believed a protein common in the lungs called TMPRSS2, which inadvertently helped previous strains of SARS-CoV-2 infect cells, struggles to grab onto the highly mutated Omicron.
Ravindra Gupta, a virologist at the University of Cambridge, told the Times Omicron has evolved in a way that helps it spread more rapidly, rather than kill its current host.
"It's all about what happens in the upper airway for it to transmit, right? It's not really what happens down below in the lungs, where the severe disease stuff happens. So you can understand why the virus has evolved in this way."
Case numbers vs deaths
After spiking rapidly in early December, daily case numbers in South Africa - where Omicron was first discovered - have plummeted, falling at almost the same heady rate in the past two weeks that they exploded. Deaths only rose minimally - the seven-day average only reaching about one-tenth what it was during the nation's mid-year outbreak.
While case numbers elsewhere are still growing, deaths aren't following the pattern set by previous waves. Ireland recorded more cases between Christmas Day and New Year's Day than it did in all of 2020, yet its seven-day average death toll has remained below 10. The UK is setting new infection records almost every day, yet deaths there have flatlined at around 100 a day - this time last year, the average was over 1200.
So could this be the beginning of the end of the pandemic? Experts expect COVID-19 to eventually become endemic - meaning it's around, but the number infected is relatively stable and it's no longer threatening to overwhelm health systems.
But whether that's an acceptable state of affairs could depend on whether Omicron patients are at risk of developing long COVID. It's estimated around a third of people who develop COVID-19 continue to suffer symptoms like coughing and fatigue long after they've recovered. Just how long it lasts remains unknown - COVID-19 is still a new disease, after all.
"We really want to know (or at least have a reasonable prediction of) how common long COVID is after an Omicron infection," Dr Blakely wrote in The Age. "To me, at least, I suspect that Omicron will induce long COVID less frequently and less severely. Why? Because it is more an infection of the airways, not the 'body'.
"But my conjecture is just that - conjecture that needs other experts to weigh in on."
Anthony Fauci, chief medical adviser to US President Joe Biden, said there's no evidence yet that Omicron will result in fewer cases of long COVID.
"Long COVID can happen no matter what virus variant occurs," he told US media on Saturday. "We should always be aware that when people get symptomatic infection … anywhere from 10 to up to 30 plus percent of people will go on to have persistence of symptoms."
Dr Blakely also said we need to know whether an Omicron infection is protective against later variants before assuming its rapid spread will help end the pandemic.
"This is obviously impossible to know definitively until the next variant hits."
Lab studies have shown Omicron antibodies do help fight off Delta.
"Maybe pushing Delta out is actually a good thing, and we’re looking at something we can live with more easily and that will disrupt us less than the previous variants," South African virologist Alex Sigal told the Times last week.
Mutation fears
But with SARS-CoV-2 constantly mutating, even 'milder' versions of the virus could be bad news if they're able to infect us repeatedly.
"Each covid infection raises the risk of creating a new 'pre-existing condition' that will make subsequent infections more dangerous," University of San Francisco computer science and medical ethicist Rachel Thomas wrote on Twitter.
"Not everyone's immune systems will be able to take the repeated hits. In a population, getting covid 1x (on average) over the next 2 years vs. 3x (on average) over next 2 years is likely to result in significant differences in how many end up permanently disabled."
She said delaying the virus as long as possible - as New Zealand is trying to do, through its managed isolation and quarantine system - will increase the chances that when it does hit, we'll have better vaccines and treatment options.
Few Kiwis have had COVID-19, compared with most other countries' populations. While our vaccination rate is up there with the best, we still haven't started vaccinating young children. Some studies have also suggested hybrid immunity - having had both a previous strain of the virus as well as the vaccine - offers the best protection, something few Kiwis have experienced.
In Australia, which has similar vaccination rates to us and until recently, case numbers, Omicron has been able to spread like wildfire. NSW Health Minister Brad Hazzard recently said basically everyone will end up getting Omicron.
Tedros Adhanom Ghebreyesus, the head of the World Health Organization, says ending the pandemic is simply a "matter of will" - urging rich countries to stop "vaccine hoarding" and let the rest of the world up their protection, reducing the likelihood of new variants emerging.
"If the right choices are taken, we can turn this pandemic around, and build on the gains made in 2021."
