Dr. Anthony Fauci

Dr. Anthony Fauci expressed "cautious optimism" Friday about the initial results from a coronavirus vaccine trial — which were widely celebrated this week — and said it remains "conceivable" that a vaccine for the deadly pathogen could be available by the end of the year.

Nightmares. Tantrums. Regressions. Grief. Violent outbursts. Exaggerated fear of strangers. Even suicidal thoughts. In response to a call on social media, parents across the country shared with NPR that the mental health of their young children appears to be suffering as the weeks of lockdown drag on.

The U.S. has the most coronavirus deaths of any country in the world — on May 11, the death toll passed 80,000.

And that's likely an undercount.

Sen. Rand Paul, R-Ky., had sharp words for Dr. Anthony Fauci, the nation's top infectious disease expert, during Tuesday's Senate committee hearing on the coronavirus.

In arguing for reopening the economy and schools, Paul said, "As much as I respect you, Dr. Fauci, I don't think you're the end-all. I don't think you're the one person who gets to make a decision."

Paul pointed to the mortality rate in New York City of young people up to age 18, which he said was near zero — much lower than for older people.

Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, will join Centers for Disease Control and Prevention Director Robert Redfield and other administration representatives in testifying before a Senate committee on May 12.

There's a chance that hundreds of millions of doses of a potential COVID-19 vaccine could be available by early next year, Dr. Anthony Fauci, a key member of the White House coronavirus task force, said Thursday, even though the federal government has not approved a vaccine against the virus.

The U.S. is calling on China to permanently shut down the country's wet markets, where the deadly coronavirus is thought to have first emerged late last year, as Australia urged an international scientific investigation of the health risks associated with them.

Updated at 6:37 p.m. ET

President Trump told governors his administration is working on publishing guidelines for state and local governments to use to determine whether to increase or relax social distancing rules to contain the spread of the coronavirus.

The announcement came ahead of the White House's regular news conference on its response to the pandemic.