What's Next For COVID-19? Experts Predict How Future Variants Will Emerge

Last winter, the Omicron variant swept past the immune defenses of much of the U.S. population and caused an unprecedented spike in cases. Vaccine manufacturers scrambled to develop Omicron-specific vaccines, but the process was too slow, and the wave subsided as quickly as it came.

The event leaves scientists wondering whether a new variant could once again catch the health community off guard. If so, what can be done now to prepare for it?

During a meeting last week of the Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee, or VRBPAC, experts discussed possible scenarios for future variants and how current vaccines could be modified to protect against them.

The panelists predicted another possible surge in COVID-19 cases next fall and winter. To have a vaccine that will protect against whichever variants are circulating at that time, scientists must get to work on developing that vaccine now.

Given the evolution of COVID-19 so far, experts speculate more transmissible offshoots of Omicron could take over. Here's what that might look like.

The Most Likely Scenario? More Omicron

BA.2 currently accounts for more than 70% of the COVID-19 cases in the U.S. The subvariant overtook BA.1—another Omicron strain—within two weeks of cropping up.

The COVID-19 virus evolves so quickly because of the adaptability of S1—the spike protein on the exterior of the virus which lets it infect cells. Scientists often compare COVID-19 to influenza, which contains a similar protein, called H1.

H3N2 is the influenza subtype that evolves the fastest. The changes in S1 of the COVID-19 virus happen more than twice as fast as the H1 in this type of influenza. In other words, in about two years of COVID-19 pandemic, the virus has changed at about five years’ worth of H3N2 evolution, said Trevor Bedford, PhD, a biostatistician and professor at Fred Hutchinson Cancer Center.

In his presentation to the FDA panel, Bedford said it’s unlikely COVID-19 will slow down any time soon. With such rapid evolution, it’s possible that COVID-19 could overcome the immunity that the U.S. population has gained through infections and vaccinations.

The most probable future for this virus, he said, is that a fall or winter wave driven by an offshoot of Omicron.

“I think we should be planning for evolution within Omicron BA.1 and BA.2 to further increase intrinsic transmission,” Bedford said. “The S1 domain in SARS-CoV-2 is a very adaptable protein and we should expect a lot of evolution going forward, and we should have methods to keep up with this evolution in terms of the vaccination platforms.”

If the next variant is indeed a descendent of Omicron, it will likely share its trait of causing relatively mild disease, Bedford said. If not, we may see a variant with higher severity.

How Likely Is a Surge From a New Variant?

The other scenario offered up by experts is that a wildly divergent variant could come out of nowhere, just as Omicron did.  

In the fall of 2021, Delta was the most prevalent strain of the virus. Within a matter of weeks, Omicron emerged and overtook it. Bedford estimated that about half the U.S. population was infected with Omicron within a mere 10 weeks.

Considering this swift overtaking has happened once before, it’s possible a new variant will cause a similar surge, he said. Though Delta is no longer circulating widely in the U.S., Bedford predicts a new variant could emerge from that strain and be even more transmissible than Omicron.

However, Bedford noted that there has been one “Omicron-like” event in 2.35 years of pandemic. It’s not clear exactly how often such an event may happen in the future, though his models predict it could be anywhere from once every year and a half to once a decade. In any case, he suggests it’s unlikely that an Omicron-like event will happen in the next year, meaning scientists should plan instead for new iterations of Omicron, as we’ve seen with BA.2.  

Christopher Murray, MD, DPhil, director of the Institute for Health Metrics and Evaluation at the University of Washington, and his colleagues use models to forecast hospitalizations and deaths in different pandemic scenarios. Their models foresee only a small bump in cases due to BA.2. If a new variant were to emerge, it could cause a much larger outbreak.

However, factors like immunity from prior infection and vaccination, access to treatments, and use of masks could keep that outbreak from getting out of control.

“Even [if a new strain has] Delta-like severity with Omicron-level of transmission or more, if antiviral access is heavily scaled up, we get a much smaller mortality peak than we saw with Delta last year or the winter peak last year,” Murray said during the panel.

How These Predictions Help Us Prepare

Predicting what future variants will look like is important for guiding the COVID-19 vaccine program. Data presented to the panel indicates that the existing mRNA vaccines are less than 70% effective at preventing symptomatic COVID-19 from Omicron, even after a booster shot. As the virus further evolves, vaccines may become even less effective.

Vaccine manufacturers are already testing new multivalent vaccines—those that can induce antibodies against multiple strains of the virus. To better guide the vaccine program, the VRBPAC will hold several more meetings in coming months to stay on top of new variants, said Peter Marks, MD, PhD, director of the Center for Biologics Evaluation and Research.

“We want people to remain confident in the safety and effectiveness of the COVID-19 vaccines,” Marks said. “Our goal here is to stay ahead of future variants and outbreaks and do our best to reduce the toll of disease and deaths due to COVID-19.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.