Some health experts and politicians warn that the United States may be entering a fourth wave of the coronavirus pandemic based on recent surges in cases, hospitalizations and deaths in some states.

“Daily cases are now growing by at least 5% in 30 states and the District of Columbia,” CNBC said. The United States recorded a “weekly average of 63,239 new COVID-19 cases per day,” which was a 16% increase compared to a week before March 29, CNBC reported from an analysis based on data compiled from Johns Hopkins University.

Experts believe cases are rising because of the reopening of businesses like movie theaters and gyms, as well as the expansion of restaurant capacity. Texas, Iowa, Florida and Alabama are among some of the states that have already reopened and eased restrictions, with some countywide exceptions.

Health experts are expecting to see localized surges in COVID-19 cases. The surge in cases can be partially attributed to better testing, which helps with detecting the virus, Professor of epidemiology at Harvard University Bill Hanage said, according to NPR.

“It’s clear, I think, that we are seeing increases in at least some states – not all states and not all at necessarily exactly the same time.”

Although not every state is experiencing a surge in cases and hospitalizations, as of April 2, the current 7-day moving average of daily new cases increased 8.4% compared to the week prior, the Centers for Disease Control and Prevention reported.

The U.K. variant B.1.1.7 has also worried health experts because of its higher infection rates.

Hanage mentioned this specific variant is “about 50% more transmissible, and also more dangerous, more likely to cause serious illness and death, given infection,” than the virus commonly seen. This means that if the variant is easier to catch, it’s still a concern for people’s health and safety.

12,505 B.1.1.7 variant cases have been reported in 51 jurisdictions as of April 1, the CDC said.

Confidence in the vaccines and fatigue from COVID-19 restrictions are making travel an appealing option to many Americans. The White House Chief Medical Advisor Dr. Anthony Fauci believes that an increase in travel has contributed to the spike in cases, as well as the elimination of mask mandates in some states.

“What we’re likely seeing is because of things like spring break and pulling back on the mitigation methods that you’ve seen. Now, several states have done that. I believe it’s premature,” Fauci said on CBS News’ Face the Nation.

“Even if on the planes people are wearing masks, when you get to the airport, the check-in lines, the food lines for restaurants, the boarding that you see, how people sometimes can be congregating together, those are the kind of things that invariably increase the risk of getting infected.”

In Florida, the new case positivity rate has increased from 5.17% on March 4 to 7.02% on April 3, according to the Florida Health Department. Florida has become a top travel destination recently because of the lack of travel restrictions. This means that states with similar guidelines could be spots for spreading COVID-19.

States that have lifted mask mandates so far include Mississippi, North Dakota and Texas. Some governors are trying to reinstate a sense of normalcy and stimulate their own state’s economy. When Mississippi Gov. Tate Reeves got rid of the mask mandate, he noted that it was up to businesses to create and enforce COVID-19 policies, Newsweek said.

But, Fauci said to CBS that although about 3 million people are being vaccinated every day, “when you’re coming down from a big peak and you reach a point and start to plateau, once you stay at that plateau, you’re really in danger of a surge coming up.”

President Joe Biden called on governors and mayors to reinstate the mask mandates. “Please, this is not politics — reinstate the mandate,” Biden said, according to The New York Times. “The failure to take this virus seriously is precisely what got us into this mess in the first place.”

CDC Director Dr. Rochelle Walensky went off-script to admit in a press briefing on March 29 that she feels a sense of “impending doom.” She said even though there is hope and there is a lot to look forward to because of vaccines, she wants people to still be careful and refrain from the easing of restrictions.

“When I first started at CDC about two months ago, I made a promise to you: I would tell you the truth, even if it was not the news you wanted to hear. Now is one of those times, when I have to share the truth, and I have to hope you will listen.”

Walensky mentioned that we still have progress to make in fighting COVID-19 and the trajectory of the pandemic in the United States looks similar to some European countries such as France and Germany, which looked like cases were decreasing, but are now experiencing a “consistent and worrying spike in cases.”

French President Emmanuel Macron ordered France’s third nationwide lockdown following a surge in cases last month. France recorded 41,907 new cases of COVID-19,  and 303 new deaths on March 31, Republic World said.

“I’m speaking today not necessarily as your CDC director — not only as your CDC director but as a wife, as a mother, as a daughter, to ask you to just please hold on a little while longer,” Walensky said.