In the 2 months because it first hit the world’s Covid-19 radar, scientists have generated an astonishing quantity of knowledge on the Omicron variant. Nonetheless, key questions stay about Omicron, in addition to a few new subvariant, often known as BA.2. Amongst them: How way more transmissible is BA.2 than its wildly transmissible dad or mum?
Answering questions like these may be difficult, generally nearly inconceivable, in lots of areas as a result of such a big proportion of individuals has been vaccinated, beforehand contaminated, or each. That may make it exhausting to tease out whether or not sure outcomes are attributable to modifications within the virus versus the results of built-up human immunity. Nevertheless it seems there’s a place the place clear solutions to key questions could also be inside attain — if that place is actually, actually unfortunate.
That place is Hong Kong.
The particular administrative area, a metropolis of seven.5 million folks crammed into 427 sq. miles in Southern China, has a singular mixture of traits at this level within the pandemic that might make it a dwelling laboratory, if town is unable to resist the onslaught of Omicron.
Hong Kong has a zero Covid coverage. Like New Zealand and the Chinese language mainland, town has largely succeeded in stopping Covid transmission from taking maintain there by requiring incomers to quarantine for 21 days in designated lodges, aggressively testing for the virus, and monitoring down contacts when circumstances emerge.
As a consequence, few folks there have been contaminated; it’s estimated that lower than 1% of residents have immune system weaponry generated by prior an infection. And although vaccination charges are excessive amongst youthful adults, they’re dangerously low among the many aged, who’re on the biggest danger of dying from Covid. Solely about 30% of adults 80 and older have acquired two doses of vaccine, based on the government’s vaccination dashboard.
The vaccination charge amongst residents of nursing houses is decrease nonetheless. “The nursing houses, we’re taking a look at 16% — one, six — at the moment,” Gabriel Leung, dean of medication on the College of Hong Kong, instructed STAT.
If Omicron have been to breach town’s formidable Covid barricades, Hong Kong’s elders could be extremely susceptible to the an infection. Issues that might seem muddled elsewhere could possibly be clear there.
For instance, it’s thought that BA.2 could also be 30% to 35% extra transmissible than BA.1, the unique model of Omicron, Leung mentioned. But when that’s true, is that resulting from one thing about how the virus behaves when it infects folks? Or is it as a result of BA.2 has acquired much more methods to slide previous human immunity than the unique Omicron virus, which was already fairly adept on the feat?
That query can greatest be answered the place there isn’t a human immunity to evade, so-called virgin territory. “Immune escape shouldn’t be a problem in case you are unvaccinated and you’ve got by no means been contaminated,” Leung mentioned.
“Mockingly, and, paradoxically, Hong Kong’s nursing houses … could be the right laboratory to kind this out,” he continued. “As a result of 84% of our older people in nursing houses will not be vaccinated, they’ve by no means been contaminated, so they’re actually immune naïve. And if now we have a BA.1 versus BA.2 in several houses, that’s really the one place on earth that this could possibly be sorted out definitively.”
Leung was fast so as to add, although, that he hopes this situation doesn’t come to cross. “It’s one pure experiment that I’d slightly not have the world first on,” he mentioned.
Hong Kong’s low vaccination charge among the many aged stems from hesitancy that arose early within the vaccination rollout when some opposed occasions have been seen after vaccination, defined Ben Cowling, a professor of infectious illnesses epidemiology on the College of Hong Kong. Elevated charges of Bell’s palsy or reactivation of shingles have been reported amongst some early vaccinees.
“In order that these have been reported within the media within the early days and bought a whole lot of consideration,” he mentioned.
In international locations the place Covid transmission charges are excessive, the risk-benefit ratio of vaccination tilts decidedly towards getting a jab. However in a spot like Hong Kong, the place for a lot of the pandemic so far the chance of catching Covid has been very low, some clinicians really suggested their aged sufferers in opposition to getting vaccinated, Leung mentioned.
“That has set the incorrect tone,” he mentioned, including the hesitancy has solidified over time. “I don’t assume that is rational, nevertheless it’s actual.”
Over the 2 years of the pandemic, Hong Kong has recorded solely 13,000 Covid circumstances and 213 deaths. That’s fewer deaths than town suffered in the course of the 2003 outbreak of SARS-1, which claimed 299 lives.
Cowling thinks continued unfold of the Omicron variant within the metropolis could also be unavoidable, regardless of the dedication of Hong Kong’s leaders to take care of town’s zero Covid standing. And with each the Delta and Omicron variants inflicting circumstances, there could possibly be infections in naïve people that might generate comparative knowledge.
“The federal government is working very exhausting to try to management the present outbreaks — and there are numerous outbreaks. Nevertheless it’s troublesome to cease Omicron,” he mentioned. “So fairly probably, we may have knowledge pretty quickly on the severity profile of Omicron in unvaccinated older folks, sadly.”
Michael Diamond, a viral immunologist at Washington College in St. Louis, mentioned a rising quantity of animal data — together with some that his lab helped to generate — factors to Omicron being much less virulent than earlier variants. There’s additionally been early human knowledge, however extra is required, he recommended, including that Hong Kong could possibly be a spot to generate it, if the virus takes off there.
“The important thing measure of whether or not that is much less pathogenic — aside from the animal research — is in naive folks, that means those that have by no means been vaccinated and by no means been contaminated. Are they getting extreme illness or not?” mentioned Diamond. “The preliminary knowledge, I’ve seen one study which suggests now that that’s certainly the case, that it’s much less pathogenic general. Nonetheless, in some folks it’s nonetheless fairly pathogenic and individuals are nonetheless dying from it.”
Natalie Dean, an assistant professor of biostatistics, bioinformatics, and epidemiology at Emory College’s Rollins Faculty of Public Well being, mentioned one of many difficult issues about making an attempt to reply questions like whether or not one variant is extra virulent than one other is that we don’t usually see each transmitting on the similar time.
Making an attempt to stack up dying charges from one level within the pandemic, when, say, the unique virus was circulating, to these accrued later within the pandemic, after one of many variants of concern had emerged, shouldn’t be an apples-to-apples comparability. Remedy of Covid has improved and many individuals have some immunity from vaccination or prior an infection.
Seeing each circulating in a inhabitants — Hong Kong’s aged — with little immunity might create a clearer image, Dean agreed.
“I’ll add too that Hong Kong has glorious knowledge assortment, and so one other benefit is that seize of infections will probably be extra full,” she mentioned.