WASHINGTON — There’s no end in sight to the coronavirus pandemic, Dr. Anthony Fauci and other top government health experts will tell Congress on Friday.

“While it remains unclear how long the pandemic will last, COVID-19 activity will likely continue for some time,” Fauci, along with Centers for Disease Control and Prevention head Dr. Robert Redfield and Health and Human Services testing czar Adm. Brett Giroir say in prepared testimony for a special House panel investigating the pandemic.

At a time when early progress seems to have been lost and uncertainty clouds the nation’s path forward, Fauci, the government’s top infectious disease expert, is calling on lawmakers — and all other Americans — to go back to public health basics such as social distancing and wearing masks.

The panel, the House Select Subcommittee on the Coronavirus Crisis, is divided about how to reopen schools and businesses, mirroring divisions among Americans.

A rebound of cases across the South and the West has dashed hopes for a quick return to normal life. Problems with the availability and timeliness of testing continue to be reported. And the race for a vaccine, though progressing rapidly, has yet to deliver a breakthrough.

Fauci’s public message in recent days has been that Americans can’t afford a devil-may-care attitude toward COVID-19 and need to double down on basic measures such as wearing masks in public, keeping their distance from others and avoiding crowds and indoor spaces such as bars. That’s echoed by Redfield and Giroir, though they are far less prominent.

Fauci’s dogged persistence has drawn the ire of some of President Donald Trump’s supporters and prompted a new round of calls for his firing. But the veteran of battles against AIDS and Ebola has stuck to his message, while carefully avoiding open confrontations with the Trump White House.

In an interview with The Associated Press earlier this week, Fauci said he was “disturbed” by the flat-out opposition in parts of the country to wearing masks as a public health protective measure.

“There are certain fundamentals,” he said, “the staples of what you need to do … one is universal wearing of masks.”

Public health experts say masks help prevent an infected person who has yet to develop symptoms from passing the virus to others. For mask wearers, there’s also some evidence that they can offer a degree of protection from an infected person nearby.