Will BA.2 Omicron ‘Stealth Variant’ Cause Another Covid-19 Coronavirus Surge?

Looks like the so-called “stealth variant” is not so stealthy anymore. It’s now clear that the BA.2 Omicron subvariant of the Covid-19 coronavirus has been spreading and spreading and spreading. Samples suggest that the BA.2 may currently account for nearly a quarter of all new Covid-19 cases in the U.S., up from about a tenth the week prior. The question then is whether this specific subvariant will fuel yet another Covid-19 surge in general?

As the Centers for Disease Control and Prevention (CDC) Covid Data Tracker shows, January 2022 is when the BA.2 subvariant first made its appearance in samples from patients in the U.S. that had been sequenced. The BA.2 originally earned it’s “stealth” nickname not because it wears a trench coat and sunglasses. Rather, unlike the BA.1 and the BA.1.1.529 Omicron subvariants, the BA.2 can be difficult to distinguish from the Delta variant on polymerase chain reaction (PCR) tests. That was a possible mistaken-identity problem back in January when the Delta variant was still being found in patient samples.

But by the time February came around, things in the U.S. had become essentially Omicron all the time. The Delta variant had been ousted by the Omicron variants like a contestant on the reality TV show Survivor. During the week ending on February 5, BA.2 was present in only about one percent of all severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) samples from patients around the country that had ended up undergoing genomic sequencing. However, in subsequent weeks, this percentage has since moved up to 2.2%, 3.8%, 6.6%, and 11.6% until reaching 23.1% in the week ending on March 5. With the BA.2 being an Omicron subvariant in an Omicron world, it may be easier to distinguish on PCR. Thus, the stealth nickname may no longer apply.

Why the BA.2 subvariant might cause another surge

The BA.2 subvariant may soon overtake the BA.1 for one big reason: it appears to be even more transmissible than the BA.1, which was already more transmissible than the Delta variant, which was already more transmissible than the Alpha variant. For example, a study in Denmark described in a preprint uploaded to medRxiv found that folks were over twice as likely to get infected when they shared a household with someone infected with the BA.2 subvariant compared to someone infected with the BA.1 variant. And recall what happened in 2021 when the “more-transmissible-than-Alpha” Delta variant arrived on the scene and then again when the “more-transmissible-than-Delta” Omicron variant arrived. Both ended up fueling something that rhymes with glue splurges: new surges.

At the same time, much of the U.S. seems to be acting as if the pandemic were over and have been ditching Covid-19 precautions as if they were sweater vests. The pandemic, of course, is not over yet with an average of over 1,200 Covid-19 related deaths per day in the U.S. over the past two weeks. Remember what happened in the Summer of 2021 after face mask requirements were relaxed as I covered for Forbes back then? And what again in the late Fall after many types of mass gatherings and travel resumed, as I covered for Forbes as well? Both times there were subsequent Covid-19 surges, which suggests that both relaxations were premature. So the lifting of Covid-19 precautions such as face mask requirements over the past month could end up being yet another round of premature relaxation. It could leave the population like someone who’s wearing nothing but a thong in the supermarket, a little too exposed.

Why the BA.2 subvariant may not cause another surge

Things are a bit different now, though, than they were in 2021. A greater proportion of the population may have at least some degree of immune protection against the Covid-19 coronavirus. More people have gotten vaccinated or infected with the SARS-CoV-2 since the Summer and Fall of 2021. Granted 65.3% of the U.S., population being full vaccinated and 44.4% being boosted against Covid-19 aren’t fantastic numbers. But this is one case where higher is better.

Data suggests that Covid-19 vaccination effectiveness against the BA.2 subvariant is comparable to what it’s been against the BA.1. For example, on March 10, the U.K. Health Security Agency reported that three doses of Covid-19 vaccines were around 69% effective against symptomatic Covid-19 caused by the BA.1 subvariant and around 74% effective against Covid-19 caused by BA.2 at the 2-week mark after the last booster dose. These numbers did drop to 49% (48 to 50%) and 46% (37 to 53%) respectively when the booster dose was given over 10 weeks ago, which is yet another reason why maintaining additional Covid-19 precautions would help.

The season may be another factor. March isn’t the same as November when the weather was growing colder and drier. In March, the conditions can be a bit temperamental like The Incredible Hulk, ranging from cold to warm. So it’s not clear how much they may favor transmission of the virus.

The BA.2 subvariant doesn’t appear to be causing more severe Covid-19 than the BA.1 subvariant

Another concern is whether the BA.2 subvariant may cause more severe Covid-19 than the BA.1 subvariant. Although the latest Winter surge further fueled by the Omicron variant did affect more people than the Summer 2021 surge, a saving grace was that the Omicron variant seemed on average to cause milder disease than the Delta variant. A study described in a pre-print uploaded to bioRxiv did raise some fur when it found that the BA.2 subvariant may cause more severe disease than BA.1 in hamsters. This may be bad news if you happen to check in the mirror and realize that you are a hamster. Of course, finding out you are a hamster could be bad news in and of itself if all of your clothes are for humans and your workplace requires clothes.

Of course, as any nightclub owner will tell you, humans are not the same as hamsters. What happens in hamsters may not necessarily happen in humans. Moreover, take any pre-print with a bucket hat full of salt. It’s not the same as a peer-reviewed study published in a reputable scientific journal. So far, data from humans have not found noticeable differences in the outcomes of those infected with the BA.2 versus the BA.1 subvariants.

There have been some warning signs of a possible impending surge

So it’s completely clear yet whether the BA.2 will fuel yet another Covid-19 surge. Warning signs have already appeared though. As I covered for Forbes on Saturday, multiple countries in Europe have been experiencing upswings of Covid-19 over the past week. Moreover, in the U.S., wastewater studies have found recent increases in the presence of the SARS-CoV-2 as Julia Raifman, ScD, MSc, Assistant Professor of Health Law, Policy & Management at the Boston University School of Public Health, recently tweeted:

So is this evidence that the horse has already left the barn, the hedgehog has already left the nightclub, and the fart has already left the pants, so to speak, when it comes to another Covid-19 surge? Well, stay tuned.