Dr. Robert R. Redfield, the director of the Centers for Disease Control and Prevention, will leave his post at noon Wednesday, as Joe Biden is sworn in as the new president.

An infectious-disease specialist with a focus on treatments for AIDS/HIV, Redfield led the public health agency during one of the most tumultuous periods in its history. He was frequently criticized for moving too slowly to protect the United States from the coronavirus, especially regarding the initial rollout of coronavirus tests, while being attacked by Trump and others within the administration for contradicting their overly optimistic scenarios of the likely course of the pandemic.

On the weekend before his departure, Redfield talked in an interview about his challenges and his disappointments.

(This interview has been edited and condensed.)

WHAT IS IT LIKE TO LEAVE NOW, BEFORE THE PANDEMIC IS OVER?

It’s hard to leave at a time when the pandemic still hasn’t reached its peak and the worst days haven’t come. It would have been more rewarding to leave when the pandemic is under control, but I do feel proud.

I encourage the president-elect to focus on his pledge to get people vaccinated in 100 days. I’m glad we gave him a foundation to build on. Last week, we had two days when we vaccinated 1 million people a day. We laid a foundation for vaccine administration. I find it unfortunate when some people suggest that the vaccine program delivering 1 million a day is somehow a disaster — but it will be a model when the Biden administration does it.

I’m not trying to criticize the Biden administration at all. But he’s pledged to do 100 million people in 100 days. We’re on the verge of delivering 1 million a day, and yet I heard his chief of staff on the Sunday talk shows saying that our vaccine program was a disaster and they inherited a mess. I’d rather they would be thankful. That’s better dialogue than political hyperbole.

WHAT WAS THE TOUGHEST PART OF THE JOB?

I really think it was trying to operationalize an effective public health response against the greatest pandemic that this nation has had in a century in an environment where there’s been probably more than 30 years of underinvestment in public health across this nation. The core capabilities — data analytics, laboratory resilience, the public health workforce — has been chronically underinvested in. That was a real frustration.

WERE YOU SURPRISED THAT IT HADN’T BEEN INVESTED IN?

I was. When we had the measles outbreak, I had some state health officials literally tracking it with pen and paper and fax machine.

When they’re talking about rebuilding infrastructure, the first infrastructure that they have to rebuild is the public health infrastructure in this nation. We need to be overprepared from a public health perspective rather than underprepared, particularly when it comes to challenging infectious pathogens. Because timing is everything — you know, what you can do in the first 36 hours, 48 hours? First week or two?

WHAT WAS YOUR GREATEST DISAPPOINTMENT?

My greatest disappointment was the lack of consistency of public health messaging and the inconsistency of civic leaders to reinforce the public health message. You can read between the lines what that means — “civic leaders.”

You can see that different parts of our society have different perspectives on what needed to be done. Controlling the pandemic was always, in my view, aligned effectively with maintaining the economic health of our nation. It wasn’t an either/or — we showed that in schools. You can still keep businesses, hospitals, et cetera, open and do it in a safe and responsible way. There are some parts of our economy that will need to have some restrictions. I would argue that having people in a crowded bar, drinking three or four beers without their masks, talking louder and louder so they spray their respiratory secretions further and further, is probably something that needs to be curtailed.

But the fact that we didn’t have an alignment meant we had the private sector and public sector all wrestling with how to put it together independently. So the reality is we are in for some very difficult times, and I think I would have loved to have been proved wrong. I still believe the worst is yet to come.

WHY HAS THE ROLLOUT OF THE VACCINES BEEN PROBLEMATIC?

First, we always said that we were going to be for some period of time — probably April, May — we were going to be in a state where demand for vaccine could outstrip vaccine availability. I look at it as an enormous accomplishment that here within, you know, six, seven months, saying we’re going to have a vaccine by the first year, basically two manufacturers are able to produce approximately 10 million doses a week.

WHAT IS YOUR RESPONSE TO CDC STAFF MEMBERS WHO SAY YOU DIDN’T STAND UP FOR THEM ENOUGH AGAINST THE WHITE HOUSE AND THE SECRETARY OF HEALTH AND HUMAN SERVICES?

First and foremost, I stood up for the agency at every turn. I never caved. I think you can find a number of people at the agency that would tell you that, who were actually in the arena with me.

There are people who say to me, “Well, why didn’t you tell the president this?” or, “Why do you tell the president that?” There are some people that will only be satisfied if you personally criticize the president. I’m a chain-of-command kind of guy.

But I’m very disappointed that some civic leaders decided to make this issue of mitigation a political football, rather than embracing the public health measures. It took a long time to really finally get through, I think, and have more consistency of messaging — probably not until late September.

DO YOU THINK SECRETARY ALEX AZAR OR TRUMP COULD HAVE HELPED YOU MORE ON THAT?

As I said, civic leaders, both at the federal and the state level, didn’t echo the critical public health measures and mitigation messages that we were trying to put out in the spring and early summer.

HAVE YOU TALKED TO THE INCOMING CDC CHIEF, DR. ROCHELLE WALENSKY?

I called her and congratulated her when she was appointed, and I gave her all my contacts and I told her that I’d be available for advice and questions. She’s been in regular contact with the people at CDC. I asked them to give her 100% of their attention.

HOW HAVE YOU BEEN GETTING BACK AND FORTH BETWEEN WASHINGTON AND ATLANTA? I KNOW YOU HAVEN’T GOTTEN A VACCINATION.

You know, I believe if I wear my mask, wash my hands and social distance, I can fly safely.

WHAT WERE YOUR LAST WORDS TO TRUMP?

In three years, I’ve kept all the conversations I’ve had with the president between me and the president. I’m going to make it all the way through.