US Will Reach Herd Immunity Threshold by Mid- Summer According to Oliver Wyman

Mar 11, 2021

  • Timing varies by state
  • New York, New Jersey, Massachusetts, and Rhode Island will reach herd immunity first
  • Maine and Hawaii will be among the last states to reach herd immunity

New York, March 11, 2021…. The United States will reach herd immunity threshold when more than 71 percent of the US population has been exposed to COVID or effectively vaccinated against it, most likely by mid-summer according to Oliver Wyman’s COVID-19 Pandemic Navigator. However, we will see significant variations by states, and should continue to watch out for the potential impact of new variants of SARS-CoV-2.

States such as New York, New Jersey, Massachusetts, and Rhode Island will reach herd immunity first -- as early as the end of May or early June -- because these states had the highest levels of infection to date (including detected cases and estimated undetected cases). Maine and Hawaii, which had low levels of infection, are predicted to be among the last states to reach herd immunity sometime after August. 

“Vaccinations will be critical for each state to reach herd immunity, especially for states with lower levels of COVID-19 infections to date,” said Ugur Koyluoglu, Oliver Wyman partner. “Despite having different guidelines on who qualifies to be vaccinated in each state, the pace of vaccination has been fast and accelerating across all states, which is good news and essential for herd immunity. Moving forward the key will be to ensure enough of the population is willing to be vaccinated.”

To watch an animated video to see when each state might reach herd immunity, please click here.

Unlike many models, Oliver Wyman’s Pandemic Navigator not only forecasts detected COVID-19 cases, but also estimates undetected COVID-19 cases historically and into the future. The model tracks and projects the number of effectively vaccinated individuals to date as well as the number of people expected to get a vaccine in the future.

If you are interested in learning more or using any of our data from the Pandemic Navigator, please contact francine.minadeo@oliverwyman.com.

About Oliver Wyman

Oliver Wyman is a global leader in management consulting. With offices in 60 cities across 29 countries, Oliver Wyman combines deep industry knowledge with specialized expertise in strategy, operations, risk management, and organization transformation. The firm has more than 5,000 professionals around the world who work with clients to optimize their business, improve their operations and risk profile, and accelerate their organizational performance to seize the most attractive opportunities. Oliver Wyman is a business of Marsh & McLennan Companies [NYSE: MMC]. For more information, visit www.oliverwyman.com. Follow Oliver Wyman on Twitter @OliverWyman.