Booker, who is vaccinated, says he first started feeling symptoms on Saturday.
"I learned today that I tested positive for COVID-19 after first feeling symptoms on Saturday. Fortunately, my symptoms are relatively mild. I'm beyond grateful to have received two doses of vaccine and, more recently, a booster -- I'm certain that without them I would be doing much worse. I encourage everyone who is eligible to get vaccinated and boosted," said Booker in a statement.
U.S. Sen. Elizabeth Warren also announced on Sunday that she tested positive for the virus.
The Massachusetts Democrat tweeted she's vaccinated, has received her booster shot and is experiencing mild symptoms in a breakthrough case of the virus.
SEE ALSO: COVID-19 'raging' in New Jersey as leaders weigh next steps
New Jersey reported back-to-back days of over 6,000 new confirmed cases on Thursday and Friday, as infections have dramatically spiked in recent weeks, state data shows. This time last month, the state was reporting under 2,000 daily new cases.
The number of people hospitalized for COVID-19 has also been on the rise in the past month, from fewer than 700 in early November to over 1,700 currently, according to state data. COVID-19 patients in intensive care units and on ventilators are also up.
"The pandemic is still in our midst and unfortunately still raging," Murphy said during a press briefing Friday. "This thing is still with us, and sadly, the numbers are going up."
State health officials have pointed to the highly transmissible delta variant, indoor gatherings, holiday travel and waning immunity as fueling that trajectory. The new omicron variant, which early data suggests is more transmissible than delta, is another challenge.