CNN  — 

Covid-19 numbers may be on the decline in the United States after a year of collective grief. But with tens of thousands of deaths expected over the next few months, experts are warning Americans not to drop their guard just yet.

“I think we are going to get fooled,” Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia said Thursday. “I think what’s going to happen is you’re going to see that as we enter the summer months, numbers are going to go down, people will think great, we’re good.”

He added: “And then, if we don’t get to what I think is going to be at least 80% population immunity from natural infection or immunization, when the winter comes, you’re going to see a surge again.”

Over the last seven days, the US has averaged 56,240 new cases per day – the lowest it has been since mid-October – and 1,437 deaths per day, which is the lowest the country has seen since November 19.

And vaccinations are picking up pace. As of Friday, more than 101 million doses have been administered in the US, according to US Centers for Disease Control and Prevention data. More than 10% of the US population has been fully vaccinated, according to the CDC, and almost 20% have had at least one dose.

But if policies stay in place as they are now, about 23,000 more people could die of the virus by April, according to a projection from the Institute for Health Metrics and Evaluation.

Yet many states have begun to relax measures, including mask mandates. And because of fewer masks and more people moving around with more transmissible variants, IHME increased its prediction of Covid-19 deaths by July 1 by an additional 22,000 people.

Overall, the IHME predicts nearly 600,000 Covid-19 deaths by July 1, up from the current number of around 530,000 recorded fatalities.

What the US does next could impact the trajectory of the pandemic, US Centers for Disease Control and Prevention Director Rochelle Walensky said in an NBC Nightly News interview.

“I think March and April are just such important, critical times,” she said. “On the one hand, you have this hyper-transmissible virus that could result in another surge after spring break.

“On the other hand, we are scaling up vaccinations so very fast, and what we really want to do is just give those vaccines a fighting chance to overcome and not let this virus surge again.”

Christy Hylton, church council vice president prepares to put up a paper heart in One United Church of Christ in Kenhorst, Pennsylvania, to represent each 1,000 deaths from Covid-19 in the state on March 3, 2021.

‘We have to be humble with this virus’

For those who are vaccinated, CDC released new guidelines Monday, maintaining recommendations against travel for those who have been inoculated.

Some have questioned whether the guidelines are too strict.

“We have to be humble with this virus,” Walensky said in the interview with NBC Nightly News. “Every time we felt like we had it under control, we had an enormous surge.”

Once more people are vaccinated and case numbers come down, the CDC may revise its guidance, Walensky said.

A year after much of the country was shut down by the virus, more than 98 million doses of Covid-19 vaccines have been administered in the United States, according to CDC data published Thursday.

About 1 in 10 people in the US – about 33.9 million people – are fully vaccinated, and close to 1 in 5 people – more than 64 million – have received one dose.

In an address Thursday, President Joe Biden promised vaccine appointments would open to all US adults by May 1, and by July 4 the US could be celebrating its independence from the pandemic.

“If July 4th comes around and your family has been vaccinated and your neighbors down the street have been vaccinated, yeah you can absolutely get together for a barbecue,” Dr. Jonathan Reiner told CNN’s Don Lemon on Thursday.

“Getting shots in the arm is not just the ticket to vaccination, it’s the ticket to getting people back in offices, to getting movie theaters open, to getting ballparks filled, to getting people back in airplanes,” he said.

A fourth vaccine may be available in the coming month or so. AstraZenea expects data from a Phase 3 study in the US of its vaccine will be available “soon, in the coming weeks,” the company said in a statement to CNN. “And we plan to file for emergency use authorization shortly thereafter.”

That vaccine is already available in the European Union, the United Kingdom and elsewhere.

Turning attention to ‘long Covid’

But even if the spread of the virus is managed within the US in the coming months, the nation will still be contending with Covid-19 survivors who suffer the effects of the disease long after they were infected, said Dr. Ashish Jha, dean of the Brown University School of Public Health.

“We know that 525,000 of our fellow Americans have died, but we also know that tens of millions have been infected, didn’t die, thankfully, and recovered. But I want to know what the long-term effects are for those individuals,” Jha told CNN’s Erin Burnett.

“I worry that we are really just seeing the tip of the iceberg when we think about long Covid, that there’s going to be a lot of disability, a lot of suffering that is going to be with us for a long time,” Jha said. “I hope that that is not true. But that’s what I worry about, and I’d like to understand that better.”

One recent study found that 30% of those with Covid-19 continue to have symptoms up to nine months after initial infection, and the National Institutes of Health has launched a $1 billion research effort into studying the long-term health effects.

CNN’s Christopher Rios, Brandon Miller, Lauren Mascarenhas, Ryan Prior and Deidre McPhillips contributed to this report.