As the pandemic continues to evolve, predicting its future has become increasingly difficult—particularly with growing pandemic fatigue and the potential emergence of new variants.
Why assessing pandemic risks is so difficult
In recent weeks, many U.S. states have begun lifting Covid-19 restrictions, including indoor mask mandates and vaccination requirements—leaving the responsibility of gauging pandemic dangers and risks to individuals.
However, people are not always good at assessing risk, the New York Times reports. News coverage, policies, personal experiences, other people's behavior, and more influence our perceptions and can lead to inaccurate judgments.
For example, a study from Stanford University found that in May 2020, the average American believed the risk of coronavirus infection was 40% while grocery shopping and 62% while on public transportation—even though less than 1% of Americans had tested positive at that point.
"We found that people drastically overestimated the risk," said Maria Polyakova, one of the study’s authors and an assistant professor of health policy at Stanford.
Judging the risks of Covid-19 can be even more difficult since prevalence of the virus is different across communities and is continually changing. The risk of severe illness also varies from person to person, meaning behaviors that are safe for one person may be dangerous for another.
In addition, Anne Rimoin, an epidemiologist at the University of California, Los Angeles, said pandemic fatigue likely plays a role in how people view the current risks of Covid-19.
"Everybody is ready for Covid to be over," Rimoin said. "It's like a kid in the back seat of a car saying, 'Are we there yet? Are we there yet?' We're not there yet."
According to Craig McKenzie, a psychology professor at the University of California, San Diego, many people are currently looking for a certain threshold where they can stop adjusting their behavior for Covid-19—and some may feel like they have already reached the threshold.
"Flu is a risk, flying is a risk, driving is a risk—we can't attend to all of them," he said. "At some point I have to act as if this doesn't matter because, if the risk is one in a million, should I change my behavior?"
The possibility of future variants
As the pandemic continues, people will also need to assess the risk of future coronavirus variants. Writing for the New York Times, Sarah Cobey, Jesse Bloom, and Tyler Starr, all experts in viral evolution, explain that the coronavirus will continue to evolve going forward, either by becoming more transmissible or developing resistance to vaccine immunity.
So far, highly transmissible variants, such as delta and omicron, have driven large surges in cases throughout the pandemic. Compared with the original coronavirus, the delta variant is around twice as contagious, and omicron is more than four times as contagious, the New York Times reports.
Currently, it is not clear how much more transmissible the coronavirus will become, but its ability to spread will eventually plateau. On the other hand, future coronavirus variants could evolve to better "escape" immunity, much like the omicron variant did.
The omicron variant has mutations in 15 of the 201 amino acids targeted by Covid-19 vaccines, but new variants could mutate in many more. According to research from the Fred Hutchinson Cancer Research Center and data from GISAID, scientists have identified more than 400 mutations in these amino acids, and there are around 2,000 other potential mutations that could occur.
And unlike transmissibility, immune escape is unlikely to plateau after a certain point. For example, some influenza viruses evolve constantly, which is why the influenza vaccine needs to be updated annually.
In addition, while the authors agree that new coronavirus variants will emerge, they are not sure how or when new variants will emerge. Typically, viral evolution occurs stepwise, which means new variants descend from recent successful ones, but that did not happen with the most recent coronavirus variant, omicron.
Instead of descending from delta, the dominant variant at the time, omicron evolved from a much older strain of the coronavirus. Although scientists are not sure how the coronavirus made the evolutionary "jump" to omicron, some suspect the variant emerged in someone with a compromised immune system, which gave the virus time to mutate.
Going forward, Cobey and colleagues write that the coronavirus could become similar to the seasonal flu, where new variants drive waves of cases every year. If this occurs, Covid-19 vaccines will need to be updated regularly, much like flu vaccines, unless broader variant-proof vaccines are developed.
Overall, the authors conclude that "[u]pdated or improved vaccines and other measures that slow transmission remain our best strategies for handling an uncertain evolutionary future." (Cobey et al., New York Times, 3/28; Karlamangla, New York Times, 3/28)