As the number of U.S. coronavirus cases passed 4.5 million on Thursday, some of America’s top public health officials will return to Congress for another round of questioning on the federal government’s handling of the pandemic.

Dr. Anthony Fauci, the nation’s top infectious disease expert, will testify Friday in front of the House’s special select committee investigating the Trump administration’s response to the pandemic, The New York Times reported. Joining him will be Dr. Robert Redfield, the director of the U.S. Centers for Disease Control and Prevention, and Adm. Brett Giroir, the administration’s point person on coronavirus testing.

The hearing will focus on testing, vaccines and school reopenings. On Thursday, President Donald Trump again stressed his desire for students to return to the classroom, the Times reported.

Fauci is expected to offer reassurances that the federal government is moving quickly but safely, while Redfield will almost certainly be questioned about the CDC’s recent shift toward favoring reopening schools. The questions for Giroir will likely center on long delays in test results across the South, the Times reported.

On the vaccine front, the final phases of testing for two potential COVID-19 vaccines were launched this week.

In one trial, the first of 30,000 volunteers will be given either a vaccine developed by Moderna Inc. and the U.S. National Institutes of Health or a placebo shot, the Post reported.

Pharmaceutical giant Pfizer also announced that it was starting a 30,000-person final phase vaccine trial, to be conducted at 120 sites globally.

Fauci predicted that researchers would probably be able to tell whether the Moderna vaccine was effective by November or December, although he added that it was a “distinct possibility” an answer could come sooner. Pfizer officials have said the company expects to be able to seek regulatory authorization or approval for its vaccine by October, the Post reported.

Contact tracing falls apart

As cases have surged and testing delays have followed, contact tracing is becoming irrelevant in many parts of the country.

In Arizona’s most populated region, the coronavirus is so widespread that contact tracers have been unable to reach even a fraction of those infected, the Times reported. The same holds true for Austin, Texas. In North Carolina, the state’s health secretary recently told lawmakers that its tracking program was hiring outside workers to try to keep up with a steady rise in cases.

In many cities in Florida, a state which has seen soaring cases counts in the past month, officials have largely given up on tracking cases, and the situation is equally grim in California, the Times reported.

“We are not doing it to the level or extent that it should be done,” Austin mayor Steve Adler told the Times. “There are three main reasons. One is the sheer number of people, the second is the delay in getting test results back, and the third is the wide community spread of the disease.”

“I think it’s easy to say contact tracing is broken,” Carolyn Cannuscio, an expert on the strategy and an associate professor of family medicine and community health at the University of Pennsylvania, told the Times. “It is broken because so many parts of our prevention system are broken.”

By Friday, the U.S. coronavirus case count passed 4.5 million as the death toll passed 152,000, according to a Times tally.

According to the same tally, the top five states in coronavirus cases as of Friday were: California with over 494,000; Florida with over 461,000; Texas with nearly 432,000, New York with over 419,000, and New Jersey with nearly 183,000.

Nations grapple with pandemic

Elsewhere in the world, the situation remains challenging.

In Hong Kong, Chief Executive Carrie Lam warned that Hong Kong faces a “large-scale community outbreak” and that the city’s healthcare system could crumble under pressure if cases continue to climb, the Post reported.

On Friday, Lam postponed elections for one year because of the pandemic, a decision that undermines one of the few partially democratic institutions left in the Chinese territory, the Post reported.

On Tuesday, Lam introduced new lockdown measures — the strictest restrictions on residents since the pandemic began. Under the new rules, group gatherings are banned along with restaurant dining, and face masks are now mandatory, the Post reported.

As Lam urged people to abide by the health and safety advice to stay home and practice social distancing regulations, she said the looming outbreak could “lead to a collapse of our hospital system and cost lives, especially of the elderly.”

Meanwhile, Vietnam’s coronavirus outbreak has spread to Hanoi and Ho Chi Minh City, the country’s two largest cities, Reuters reported. New cases have also been detected in Vietnam’s central highlands, known as the “coffee belt.”

Vietnam had gone more than three months without reporting any locally transmitted coronavirus cases. The country has yet to record a single death linked to COVID-19, Reuters reported.

Things continue to worsen in India. On Friday, the country passed 1.6 million infections and almost 36,000 deaths, a Johns Hopkins tally showed. The surge comes weeks after a national lockdown was lifted, and it’s prompted some parts of the country to revert back to stricter social distancing measures. Only the United States and Brazil have higher caseloads.

Brazil is also a hotspot in the coronavirus pandemic, with over 2.6 million confirmed infections by Friday, according to the Hopkins tally. It has the second-highest number of cases, behind only the United States.

Cases are also spiking wildly in Russia: As of Friday, that country reported the world’s fourth-highest number of COVID-19 cases, at nearly 838,000, the Hopkins tally showed.

Worldwide, the number of reported infections passed 17.3 million on Friday, with nearly 674,000 deaths, according to the Hopkins tally.

More information

The U.S. Centers for Disease Control and Prevention has more on the new coronavirus.