The national surge in COVID-19 cases fueled by the highly transmissible omicron variant may last weeks, rather than months, according to the most recent projections from the COVID-19 Scenario Modeling Hub, a consortium of researchers helping the CDC track the pandemic's trajectory.
The latest ensemble projection combines eight different models from various academic institutions, including Baltimore-based Johns Hopkins University and the University of Notre Dame (Ind.). Researchers developed four different scenarios that factor in various levels of omicron's transmissibility, illness severity and ability to evade natural immunity.
Five takeaways:
1. Every scenario projected the omicron wave "to be sharp and fast," with most models forecasting cases and hospitalizations peaking by the end of January, researchers said in a Jan. 4 note about the new models.
2. The rate of new cases, hospitalizations and deaths is projected to decelerate through mid-March but could remain elevated compared to the lowest levels seen during the pandemic in June 2021.
3. The models project that the U.S. will see between 391,000 and 2.04 million cumulative hospitalizations and 44,000 to 298,000 deaths between the modeling period of Dec. 19, 2021, and March 12, 2022.
4. Hospitalization and death tallies vary by scenario. In scenario A — defined by optimistic omicron severity, high immune escape and low transmissibility increase — the ensemble median estimate is 750,000 hospitalizations. In scenario B — defined by optimistic severity, low immune escape and a high transmissibility increase — 822,000 hospitalizations are projected.
5. Researchers cautioned that substantial uncertainty about omicron's epidemiology and severity could substantially affect projections.
"Even the best models of emerging infections struggle to give accurate forecasts at time scales greater than three-four weeks due to unpredictable drivers such as a changing policy environment, behavior change, the development of new control measures, and stochastic events," they said. "However, policy decisions around the course of emerging infections often require projections in the time frame of months. The goal of long-term projections is to compare outbreak trajectories under different scenarios, as opposed to offering a specific, unconditional estimate of what 'will' happen."
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