A new wave of COVID – or nothing to worry about? The best and worst scenarios for what comes next

What is currently happening with COVID?

Amid the chaos and controversy that followed a decision of the federal judge to repeal the US mask mandate for travel earlier this week — a decision the Justice Department is now appealing — it was easy to overlook the fact that mask policies weren’t alone. getting more confusing by the day

The pandemic itself has probably never been more difficult to parse.

On the one hand, cases have surged in 41 states in the past two weeks, raised from their post-Omicron trough by an even more transmissible sub-variant called BA.2.

On the other hand, BA.2 has been dominant in the US for about a month – and the number of cases is rising about a tenth as fast as in the first month of Omicron’s reign, increasing by 46% between March 20 and April 20 compared by 475% between December 15 and January 15.

On the other hand, the US reports on average only about 900,000 tests per day – a fraction of the 2.5 million registered at Omicron’s peak. As Americans switch to rapid home testing, or don’t bother testing at all, we are counting infections more than before

A pedestrian wearing a baseball cap and a checked hooded jacket is shown against a bright red background.

A pedestrian in a surgical mask in Philadelphia. (Matt Rourke/AP)

Still, hospital admissions recently hit a low of around 15,000 and have barely moved for weeks, while the number of ICUs has plummeted to their lows. lowest level since the start of the pandemic — another stark contrast to winter, when hospital admissions more than doubled to a record high of 160,000 between December 20 and January 20.

This could be a sign, some experts say, that infection- and vaccine-induced immunity is attenuating the most severe effects of the latest variants, a development they hope will usher in a less dangerous and disruptive phase of the pandemic.

Or, as other experts argue, it could just be the usual delay between cases and hospitalizations.

As we said, a mind-boggling moment. So rather than predicting the future — never a wise move with the SARS-CoV-2 virus — here are three different ways it could happen in the weeks and months ahead.

The worst case scenario

In recent days, it has become clear that BA.2, which has been slowly spreading across the US since December, is no longer the only sub-variant in the city. It’s not the strongest either. Instead, BA.2.12.1 — a subvariant of a subvariant — now seems to outperform its predecessor in bellwether states such as New York and Massachusetts

According to estimates of odd proportions from the Centers for Disease Control and Prevention, BA.2 has been responsible for more than 70% of U.S. infections since early April. But the growth stopped there. Meanwhile, BA.2.12.1 is up from just 3.3% of infections at the end of March to 19% as of April 16.

A purple plate with a pig named Philbert in a salmon pink mask.

A sign at the Reading Terminal Market in Philadelphia. (Matt Rourke/AP)

In other words, BA.2.12.1’s share roughly doubles every week – 2.5 times faster than BA.2’s. This implies an important “transmission advantage:says Dr. Eric Topol, director of the Scripps Research Translational Institute — one who “comparable in magnitude to the perceived advantage of BA.2 over BA.1said Trevor Bedford, a leading virologist at the Fred Hutchinson Center in Seattle.

“The BA.2 wave in the United States is… changing [in]to the BA2.12.1 wave,” Topol recently tweeted

Why? Probably because BA.2.12.1 has an additional spike protein mutation (L452Q) which, in a slightly different form (L452R), “appeared to play an important role in promoting the spread of [the] Delta variant,” said Bedford.

Meanwhile, the similarly mutated BA.4 and BA.5 sublines are spreading rapidly in South Africa

“The hypothesis is then that 452R/Q provides an additional intrinsic transmission advantage,” Bedford has explained† “Looking ahead, I expect these 452R/Q sublines to continue to expand.” The question is how much damage they do as they spread. The main reason BA.2 has gone so much slower than Omicron BA.1 in the US is that a huge percentage of the population — as much as half – just had Omicron BA.1, which confers some degree of immunity to reinfection. If BA.2.12.1 (and BA.4, BA.5) can get around some of that immunity, it could turn the current wave of business into more of a wave. And while vaccines and especially boosters have so far shown an extraordinary ability to protect recipients from serious illness and death, millions of seniors remain unvaccinated and/or unboosted; long COVID looms as a real concern† and it’s still unclear how much immunity wanes over time.

So the worst-case scenario is that these new sublines take advantage of the United States’ persistent vulnerabilities — including a steady decline in masking — and cause more serious illness than BA.2 alone would have done.

An airport lounge full of passengers up close, only a few in masks.

Travelers at Miami International Airport on Friday. (Daniel Slim/AFP via Getty Images)

The best scenario

The good news is that there is no sign of anything in the US approaching the earlier waves of hospitalization and death yet.

National numbers (which have hit record lows again) aren’t particularly helpful here as BA.2 and BA.2.12.1 have risen especially in the Northeast. But the numbers from New York and Massachusetts (the leading BA.2.12.1 states) are perhaps more illuminating.

In the past two weeks, the number of cases has increased by 62% in New York and 51% in Massachusettss. The number of hospital admissions has also increased. But crucially, the number of IC shots has remained remarkably flat and low. In New York, ICU numbers as a percentage of total hospital admissions (at 11%) are at an all-time low. The same is true for Massachusetts (at 8%). Similarly, only 111 (or 29%) of the state’s nearly 400 hospitalized patients are classified as “hospitalized primarily for COVID-19-related illness”; at Omicron’s peak, that number was over 50%. Another telling statistic: a full 62% of patients in Massachusetts currently hospitalized with the COVID report that they were fully vaccinated when they tested positive; before Omicron, that number was consistently closer to a third.

So for now, it appears that more patients in bellwether states are testing positive for COVID upon hospitalization, as more people test positive for COVID in surrounding communities – but BA.2 and BA.2.12.1 are not increasing serious illnesses, probably due to vaccination.

A man without a mask passes through a COVID testing site.

A COVID-19 test site on a street corner in Brooklyn, NY, on Monday. (Spencer Platt/Getty Images)

Whether this pattern will hold up as BA.2.12.1 increases in prevalence remains to be seen. But according to the CDC, the new subvariant is already is responsible for more than 50% of infections in the New York area — and rates from case growth and test positivity may start to level off. in Massachusetts, wastewater prevalence and cases both seem to have reached a plateau; meanwhile, fallen in Washington, DC, may be starting to decrease

Coming out of a BA.2/BA.2.12.1 bump relatively unscathed could be a good sign for the future.

according to Bedfordthere are two plausible scenarios for the next year: (1) another “Omicron-like emergence” in which a “new, wildly diverse virus” evades existing immunity and turns society upside down again, or (2) “evolution within BA.2” to “further increase intrinsic transmission”, which causes “lower attack rates”, largely “driven by drift + decreasing [immunity] + seasonality.”

Bedford considers the second, stable, flu-like scenario “more likely” – saying that the more sublines like BA.2.12.1 appear, the more likely it will become.

“The more time that passes, the more certain we can be that there will be no new ‘Omicron-like’ emergence,” he said. has explained

A woman in a blue mask passes two small unmasked boys.

A pedestrian in Philadelphia wears a surgical mask. (Matt Rourke/AP)

If Bedford is right, that suggests that future peaks are less like our huge winter Omicron wave than what we’re experiencing now. And it would also increase the “probability that we’ll eventually switch to” [a] vax with [an] Omicron backbone,” according to Former Food and Drug Administration Commissioner Scott Gottlieb – meaning more stability, predictability and protection against infection in the future

The most likely scenario

Possibly somewhere in the middle. BA.2.12.1 is responsible for only 20% of current infections in the Massachusetts region; maybe it will take flight and undo the recent progress there. Or perhaps high vaccination and booster rates in the Northeast are attenuating the variant’s ultimate impact there — while lower rates this spring make fewer COVID-cautious states more vulnerable. Or maybe seasonality and warm weather will help protect the South and West as they did last spring and summer.

On Twitter, a respected COVID modeler going for the handle @JPWeiland Posted a prediction earlier this week† Based on recent BA.2.12.1 growth rates, the modeler said the variant “has a greater chance of breaking the shift in seasons to create a real wave than BA.2 could muster,” but went on to say. saying that because there isn’t much expected immune escape with B.2.12.1, the wave should be inherently limited in size. “We won’t see close to 1 million cases per day in January, but we could see 200k. Hard to say for sure.”


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