New Jersey is among a handful of states seeing a COVID surge.

The number of new COVID-19 infections has been dropping dramatically nationwide since January when cases surged after the December holidays. New Jersey is among five states that are bucking that trend.

The latest state-by-state data compiled by Johns Hopkins University finds nearly half of all new reported infections over the last seven days have come from New Jersey, New York, Pennsylvania, Michigan and Florida. Those states account for 22% of the nation's population, but 44% of all new infections.

The reasons why New Jersey and these other state are seeing a big spike is not entirely clear. State health officials have pointed to the rise of COVID mutations that are more easily spread as a main factor in New Jersey experiencing a third wave of infections. The U.K. variant is the most prevalent mutation in New Jersey, and is the same variant that had been sweeping across Europe causing a wave of new infections.

Lifting of restrictions does not appear to be a major factor. New Jersey and New York have among the tightest restrictions. Michigan and Pennsylvania have relaxed many restrictions but have moderate controls still in place. Florida has almost fully reopened and lifted most restrictions.

Despite New Jersey in reach of the goal of vaccinating 70% of the state's adult population, Gov. Phil Murphy has not further relaxed restrictions. He continues to cite the rise of COVID variants as the reason why indoor dining limits and other restrictions remain in place.

In Michigan, some have been pressuring Gov. Gretchen Whitmer to impose a two-week lockdown to stop the surge. She has been reluctant to do so.

In Florida, even with COVID cases surging after Spring Break, few restrictions remain in place.

Even as he announced vaccination milestones, President Joe Biden cautioned against lifting restrictions.

"What we do now," Biden said, "will determine how many people we save or lose in April and May and June, before we get to July 4."

In New Jersey, and nationally, the pace of vaccination has been increasing. Biden announced 150 million shots had been delivered since he took office in January. New Jersey is set to pass 5 million doses given as early as this week.

Some health experts are suggesting New Jersey and other states with high infection rates should get vaccine priority from the Biden administration. Dr. Kirsten Bibbins-Domingo is chair of the University of California at San Francisco's department of epidemiology and biostatistics. She told the Associated Press other states would not be hurt by the diversion of vaccine to high infection rate states. She argued it would, in fact, help the entire nation stop the pandemic because "more vaccine needs to be where the virus is."

(The Associated Press contributed to this story)

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