A US public health chief told Congress on Tuesday that coronavirus has “brought this nation to its knees” as America struggles with more than 2.3 million confirmed cases and more than 121,000 deaths so far. Dr Robert Redfield, director of the federal Centers for Disease Control and Prevention (CDC), told a hearing in Washington that core public health capabilities in the US had been vastly underfunded for a long time and needed urgent investment. “We have all done the best that we can do to tackle this virus and the reality is that it’s brought this nation to its knees,” Redfield told the House energy and commerce committee. “We are probably going to spend $7tn because of one little virus,” he added. He said that the US had “used the capacity that we have” to confront the pandemic but that “the critics will be there”. The Trump administration has been heavily criticized for a slow and shaky early response to coronavirus as it spread from Asia and Europe to the US in early 2020, especially as Donald Trump repeatedly downplayed the risk of Covid-19 and the damage it would come to wreak upon the US. Redfield said that the US at local, state and federal level has chronically underinvested in “the core capabilities of public health”, including data analysis, “laboratory resilience”, the public health workforce, emergency response capabilities and “our global health security around the world”, adding that “now is the time” to step up spending. Earlier in the hearing, Dr Anthony Fauci, the US’s top infectious disease expert testified that the country will be doing more Covid-19 testing, not less, hours after the president insisted he was serious when he said at a rally at the weekend that he had called for testing to slow down in the US. Coronavirus cases have continued to rise in about half of US states, but Trump said at the rally in Tulsa, Oklahoma, that increased testing was making the US look bad and that he had asked staff to slow down. His press secretary later said the remarks were “in jest” but the president stood by them on Tuesday, telling reporters that the comments weren’t a joke. Speaking to the congressional committee hours later, however, Fauci said: “I know for sure that to my knowledge none of us have ever been told to slow down on testing. That just is a fact. In fact, we will be doing more testing.” Fauci, a member of the White House coronavirus task force, spoke to the committee alongside Redfield; the head of the Food and Drug Administration, Stephen Hahn; and a top official at the Department of Health and Human Services, Brett Giroir. Fauci last testified before Congress in May, when states were still mostly shut down. Since then staggered reopenings have taken place across the country, and several states are seeing a concerning increase in cases. He said the state of coronavirus in the US was overall a “mixed bag”, in part because of the country’s huge size and diversity. He said some areas, such as New York City, had done well to rein in cases by following the government’s guidelines for reopening, but said the “disturbing surge” in infections in other parts of the country was very concerning. “The next couple of weeks are going to be critical to address those surges we’re seeing,” Fauci said, specifically citing the increase in cases in Florida, Arizona and Texas. The concerns shared by top health leaders at the hearing contradicted Trump’s continued efforts to downplay the effects of Covid-19. At least eight Trump campaign staffers tested positive for Covid-19 in Tulsa, where Trump told a campaign rally that he had asked administration officials to slow down testing, because too many positive cases are turning up. After administration figures including White House press secretary Kayleigh McEnany suggested the comments weren’t serious or were a joke, Trump on Tuesday said: “I never kid.” “Testing is a double-edged sword,” Trump told reporters. “One way, it shows you have cases and in another way you find out where the cases are and you do a good job.” When asked individually at the congressional hearing if the president had asked the US health leaders to slow down testing, they all responded “no”. At the time of the May hearing, Fauci was one of many speakers to testify from a video feed at home. This time, the speakers were in person for this hearing. In the chamber, the men sat with tubs of disinfectant wipes and hand sanitizer pumps next to their nameplates. While committee members and speakers are usually packed tight, people sat at a distance, wearings masks, which they removed to speak. Fauci told the committee he was “cautiously optimistic” that a vaccine would be ready at the end of the year or early 2021. The group also expressed concern about what could happen if coronavirus cases were still high when flu season arrives in the autumn. In a prepared statement, the experts said such a collision could again burden the country’s healthcare system. “If there is Covid-19 and flu activity at the same time, this could place a tremendous burden on the healthcare system related to bed occupancy, laboratory testing needs, personal protective equipment and healthcare worker safety,” the statement said. Associated Press contributed to this report