What’s the outlook for COVID-19 and flu this fall and winter? It’ll probably be a lot like last year, experts say.
“We currently expect this flu season to be comparable to last year’s season,” said Adrienne Keen, PhD, of the Centers for Disease Control and Prevention’s (CDC) Center for Forecasting and Outbreak Analytics. “We expect this year’s COVID-19 season peak to be similar to last year’s or lower.” The CDC is still analyzing COVID surveillance data from the summer and will update the forecast as more is learned.
For COVID, that means it won’t be as bad as the pandemic years, and for the flu, it’s a typical pre-pandemic season. But status quo does not mean great.
Between October 2023 and April 2024, as many as 75 million people got the flu in the United States, according to CDC estimates, resulting in up to 900,000 hospitalizations and between 17,000 and 100,000 deaths. In 2023, about 900,000 Americans were hospitalized with COVID and 75,000 died.
But unknowns — such as a COVID variant that takes off quickly or a surprise influenza strain — could knock that forecast flat. Getting vaccinated remains crucial, public health officials stressed.
Predicting COVID
Two key predictors of how bad an upcoming COVID season will be are the cycling of new variants and the population’s immunity (protection from an infectious disease that happens when a population is immune through vaccination or previous infection).
When new variants go up and immunity goes down, “we tend to see the increase in cases,” said Michael T. Osterholm, PhD, MPH, director of the Center for Infectious Disease Research and Policy and a professor of public health at the University of Minnesota, Minneapolis. But if the number of variants goes down and immunity levels go up, the outlook is more favorable.
The new COVID variant called XEC has been found in at least 25 states. On September 27, the CDC added the variant to the COVID tracker. It now accounts for 6% of US cases. This was expected, as the variant has been circulating in Europe, said Amesh Adalja, MD, a senior scholar and infectious disease expert at the Center for Health Security at Johns Hopkins University, Baltimore, Maryland.
“There will always be a new variant appearing, and one falling,” he said. “So the fact that this is happening is not surprising.”
Meanwhile, the summer COVID surge has provided postinfection immunity for some people. “What’s likely is, we are going to see substantial protection of the population for several months based on previous infection and in some cases vaccination,” Dr. Osterholm said. That means protection from serious illness, hospitalizations, and deaths (but not necessarily infection). That protection could last through the year or into early 2025.
The timing of 2024’s winter surge will likely be a bit later than 2023’s, said Andrew Pekosz, PhD, a professor and vice chair of molecular microbiology and immunology at Johns Hopkins University, Baltimore, “peaking just after the Christmas/New Year holiday.”
During the 2023-2024 season, weekly COVID hospitalizations peaked the week of Dec. 30, said Justin Lessler, PhD, a professor of epidemiology at the University of North Carolina at Chapel Hill and a member of the COVID-19 Scenario Modeling Hub.
But variants are unpredictable. “There’s a chance that the XEC variant may take off and spread, or might not,” said Dr. Adalja. As of September 28, the Omicron variant KP.3.1.1 was leading, accounting for 58.7% of US cases, according to the CDC.
While Dr. Adalja agreed that 2024’s COVID season will probably be like 2023’s, “we have to be prepared for cases and hospitalizations going up,” he said, “but not to the point of a crisis.” A return to lockdowns and social distancing is unlikely.
Still, older adults and others at higher risk of getting very sick from COVID should consider masking during travel, said Rajendram Rajnarayanan, PhD, MSc, an associate professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro.