Dr. Anthony S. Fauci, the director of the National Institute for Allergy and Infectious Disease and the government’s top infectious disease expert, said during a Senate hearing Tuesday that the U.S. is “not in total control” of the country’s coronavirus outbreak.

“We are now having 40-plus thousand new cases a day,” Dr. Fauci said. “I would not be surprised if we go up to 100,000 a day if this doesn’t turn around. So I am very concerned.”

Dr. Fauci appeared before the Senate Health, Education, Labor and Pensions Committee alongside Admiral Brett Giroir, the assistant secretary for Health and Human Services; Dr. Stephen Hahn, the Food and Drug Administration commissioner; and Dr. Robert Redfield, director of the Centers for Disease Control.

Dr. Redfield said hospitalizations are rising in 12 states and daily deaths are up in Arizona. Dr. Fauci said he was concerned about the recent surge in coronavirus cases and the curves in some states show that, “we are going on the wrong direction.”

Dr Fauci stated that some states opened up too quickly. “When states start to try and reopen again, they need to follow the guidelines that have been very carefully laid out with regard to checkpoint,” he said, adding that school administrators must take into account the dynamics of the outbreak in their region if planning to reopen in the fall.

As for vaccine development, Dr. Fauci said he could not guarantee that “we’ll have a safe and effective vaccine.”

“But we are cautiously optimistic, looking at animal data and the preliminary data, that we will at least know the extent of the efficacy sometime in the winter and early part of next year.” Dr. Fauci said.

Dr. Hahn acknowledged that people are skeptical of vaccine development efforts. The F.D.A. commissioner noted that all phases of development should include diverse populations and the accelerated timeline for development would not come at the expense of safety.

“We will ensure that any vaccine that comes before us, whether for authorization or approval, meets our stringent standards for safety and effectiveness.” Dr. Hahn said.

Dr. Fauci said at the hearing that the federal government had a “community engagement program” embedded within the sites of vaccine trials to help build trust.

“We are aware of the reality: a lack of trust of authority, a lack of trust in government and a concern about the vaccines in general,” Dr. Fauci said. He added that the government should engage the community by “boot on the ground”, especially near minority populations that “have not always been treated fairly by the government.”

“We are all in this together,” Fauci said. “What was thought to be unimaginable turned out to be the reality that we are facing right now.”