Infections, hospitalizations, and deaths are steadily declining in the US. The main driver of this decline is seasonality, aided by expanding levels of vaccination. However, the spread of the B.1.1.7 variant may counteract the combined effect of seasonality and vaccination; today it likely accounts for less than 20% of infections but is expected to account for approximately 80% by late April. 

The most uncertain driver of the trajectory of the epidemic over the next four months is human behavior, specifically how individuals will respond to steady declines in daily cases and deaths. If most individuals remain careful, maintaining mask-wearing through April or longer, we expect that there will be a further 103,000 deaths from now until June 1, leading to a cumulative death total of 589,000. More rapid increases in mobility or reductions in mask use can easily lead to increasing cases and deaths in many states in April. So far, reported mask use remains high at 77%, but mobility has started to increase. 

Managing the epidemic in the next four months depends critically on:  

• Scaling up vaccination and trying to increase the fraction of adults willing to be vaccinated above three-quarters. 
• Strongly encouraging continued mask use and avoiding situations where transmission is likely, such as indoor dining, going to bars, or indoor gatherings with individuals from outside the household. 

Despite the favorable trends in the epidemic, we do not expect to reach herd immunity prior to next winter. 

*This week, we have been able to incorporate additional information that has become available on how the new variants are spreading around the world. The scale-up of new variants, which is included in our reference scenario, is based on data from more than 15 locations. We will continue to update this as more information becomes available. 

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Updated: February 20

Questions?

Contact:

David Carter | Director, Health Care Finance & Policy

C 360.888.5702