Even as the White House on Wednesday sought to reassure Americans that the economy would not suffer another sweeping shutdown, signs emerged that the country is slipping back toward its pandemic past, with hospitals overrun, mandates reinstated and events postponed.

The culprits behind these unwelcome developments: two coronavirus variants — delta, which is still fueling surges across the country, and omicron, which appears more transmissible and is likely to propel the next wave of infections, officials warn.

The worrying trend lines have compelled states such as California and New York to reimpose indoor mask mandates, while some universities and school districts have moved classes and activities online. On Broadway, several high-profile shows have canceled performances, citing virus cases among the cast or crew. And new rounds of infection have also hit major sports leagues, with stars sidelined and games postponed.

Still, Jeffrey Zients, President Biden’s coronavirus response coordinator, projected confidence at a Wednesday briefing, telling reporters: “We are in a very different and stronger place than we were a year ago. And there is no need to lock down.”

Here’s what to know

  • Pfizer’s anti-covid pill prevents severe illness and should work against the omicron variant, the company announced Tuesday.
  • An omicron-specific vaccine is not needed at this time because early data indicates existing booster shots should provide protection, especially against severe disease, said Anthony S. Fauci, the nation’s top infectious-disease expert.
  • The United States on Tuesday surpassed 800,000 deaths from the coronavirus as the pandemic approaches the end of a second year.