The nation’s top infectious disease specialist warned Tuesday that the United States could see up to 100,000 new cases per day of the virus that causes COVID-19 if the nation does not take steps to control the pandemic.

Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, told the Senate Health, Education, Labor and Pensions Committee that he’s concerned the number of new cases per day could rise from the current rate of about 40,000 new cases a day.

“I would not be surprised if we go up to 100,000 a day if this does not turn around,” Fauci said.

Tuesday’s hearing came as the administration has been grappling with cases rising in 35 states, according to a tally by The New York Times. Officials in a handful of states have paused their efforts to reopen with cases increasing.

Robert Redfield, the director of the Centers for Disease Control and Prevention, testified that hospitalizations are rising in 12 states and that the daily death rate is increasing in Arizona.

Officials reiterated their calls for Americans to think about their social responsibility to protect people who are more vulnerable and to lower the risk by social distancing, wearing masks and washing their hands.

“There’s just more and more data showing that the use of face coverings and masks are an effective way to prevent transmission,” Redfield said, adding that the practices of keeping distance, wearing masks and washing hands were the “best recommendations I can tell you.”

Senate HELP Chairman Lamar Alexander called on President Donald Trump to wear a mask at times in an effort to make it less of a political statement.

“The president has millions of admirers,” the Tennessee Republican said. “They would follow his lead. It would help end this political debate. The stakes are too high for it to continue.”

Alexander said wearing a mask may have helped prevent him from contracting the virus after coming in contact with a staffer who was pre-symptomatic.

“The Senate physician told me one reason that I did not become infected was because the staff member was wearing a mask and that greatly reduced the chances of exposure,” he said.

Vaccine concerns

Sen. Tina Smith, D-Minn., raised concerns about an “October surprise,” in which the administration might announce a vaccine ahead of Election Day to score political points, and asked how the public can have confidence that an eventual vaccine is safe and effective.

Food and Drug Administration Commissioner Stephen Hahn noted that the agency released guidance Tuesday for the biopharmaceutical industry about what scientific evidence the agency needs to see before authorizing a COVID-19 vaccine.

“We will use the science and data from those trials and we will ensure that our high levels of standards for safety and efficacy are met,” he said.

Any vaccine must show at least 50 percent efficacy against a placebo and must be safe, the guidance said. The FDA clarified that any drugmaker seeking to make a vaccine available before full approval through a temporary emergency use authorization would still need to demonstrate that it was safe and effective.

The FDA will also require data on the consistency and safety of the manufacturing process. Some drugmakers are working with the U.S. government through the Trump administration’s Operation Warp Speed vaccine development initiative, and others are developing a vaccine independently.

Sen. Patty Murray, the HELP panel’s ranking member, called on the administration to release a national plan for vaccinations to avoid some of the pitfalls the nation has faced with testing for the virus in recent months.

“The ongoing struggle to get President Trump to take testing seriously should be a stark warning to Congress that when it comes to vaccines, we can’t just leave this administration to its own devices — we have to hold it accountable,” the Washington Democrat said.

Officials hope a vaccine will be available at the beginning of next year.

Plans for reopening schools 

While Tuesday’s hearing focused on various parts of the country’s response to the pandemic, several senators focused on plans for schools to reopen.

Fauci said plans to reopen schools would likely differ in different regions of the country. Local officials may need to adapt and shift to options for online learning or having students in the classroom less frequently if a school needs to modify schedules.

Sen. Rand Paul, R-Ky., said other nations have reopened schools and not seen an increase in cases since doing so.

“I feel very strongly we need to do whatever we can to get the children back to school,” Fauci said.

The CDC released updated guidance Tuesday on COVID-19 testing for colleges and universities to consider and is set to release guidance for K-12 schools later this week, Redfield said.

Flu season and a new virus

Redfield said the CDC is working to build confidence in the influenza vaccine ahead of the upcoming flu season, particularly among groups that have been less likely to get the vaccine in the past. Flu vaccine manufacturers have increased their manufacturing efforts and have committed to offer almost 189 million doses of the vaccine, he said.

The agency also purchased 7.1 million doses of the vaccine, up from its normal purchase of about 500,000 doses, for state and local health departments to give uninsured adults, he said. The agency has also upped the availability of the children’s vaccine program, since more children will likely be eligible for the program with higher unemployment rates this year.

Fauci also addressed reports of a new strand of swine flu that researchers in China have identified in pigs that has similar traits to the 2009 H1N1 flu and the 1918 flu. That strand, which researchers are calling G4, is still being examined and is “something we need to keep our eye on,” he said.

Emily Kopp contributed to this report.