As the news that President Donald Trump had tested positive for the coronavirus and was hospitalized rocked the presidential campaign on Friday, questions of potential exposure rippled into Pennsylvania and New Jersey, both of which Trump had visited in recent days.

New Jersey Gov. Phil Murphy urged anyone who had been at a fundraiser with Trump at his golf course in Bedminster on Thursday, held hours before the president tested positive, to self-quarantine and be tested.

Pennsylvanians who attended Trump’s rally outside Harrisburg last Saturday only need to get tested if they feel sick, Gov. Tom Wolf’s administration said. A Department of Health spokesperson encouraged attendees to download the COVID Alert PA app, which people who test positive can use to anonymously alert others they came in contact with.

“The commonwealth at this point has no formal recommendations for anybody who attended those rallies,” Wolf said, “but anybody who has been in any crowd of any sort for any reason, and they find that there are people who have tested positive for COVID-19, you need to be very, very careful.”

Democratic presidential nominee Joe Biden, who debated Trump on Tuesday in Cleveland, spent part of the week in Pennsylvania, taking a chartered Amtrak tour through the western part of the state. His campaign events were socially distanced but drew crowds. Biden and his wife, Jill, tested negative for the virus Friday.

It generally takes two to 14 days for symptoms to develop after someone is infected, and there is an incubation period after someone is infected before they will test positive.

In New Jersey, Murphy said contact tracing had begun for the Bedminster event.

“If you just get tested today, you won’t have given the virus enough time to incubate,” Murphy said at an afternoon news conference, citing his health department’s testing recommendations. “Wait five or seven days ... and get tested. Even then, if you test negative, you really have to stay off the field for the full 14 days, and probably would want to get tested again after that period.”

Counselor to the President Hope Hicks, left, cheering without a mask on during President Trump's a campaign rally at Harrisburg International Airport last Saturday. Hicks tested positive for the coronavirus on Thursday.
Evan Vucci / AP
Counselor to the President Hope Hicks, left, cheering without a mask on during President Trump's a campaign rally at Harrisburg International Airport last Saturday. Hicks tested positive for the coronavirus on Thursday.

Trump attended the private fundraiser even though his staff knew aide Hope Hicks had tested positive for the coronavirus and had been experiencing symptoms. Just before the trip to Bedminster, the contact tracing process had “already started,” White House Chief of Staff Mark Meadows said Friday morning.

Hicks' test result became known as Marine One was taking off for the New Jersey trip, Meadows said. Hicks and some others were removed, but the rest of the entourage went ahead. The White House press secretary said Friday that “White House operations” had decided it was safe for Trump to continue to New Jersey.

Hicks, the former White House communications director, had traveled with Trump to Pennsylvania for the Saturday evening rally. In addition, two people who had attended a White House event on Saturday afternoon — U.S. Sen. Mike Lee (R., Utah) and the Rev. John Jenkins, president of the University of Notre Dame — announced Friday they had the virus.

“What happened with the president and his wife ... underscores the fact that this is a disease that will take every opportunity to spread,” New Jersey Deputy Health Commissioner David J. Adinaro said. “To use the president as an example ... we’re potentially all vulnerable to this disease.”

Adinaro also pointed to New Jersey’s rising case numbers. A recent spike in cases in Ocean County in particular has drawn concern from state health officials. Murphy spoke Friday from a round-table discussion in Bayville, Ocean County, joined by local elected officials, school officials, and community and religious leaders.

The state has recorded more than 1,200 new cases in the county over the last week, Health Commissioner Judith Persichilli said, 840 of which came from Lakewood, home to a large Orthodox Jewish community.

While she said there was no single event associated with the spike, officials said large religious observances in recent days may have resulted in close contact between people. State officials have also received reports of weddings and funerals where attendees were unmasked and did not follow social distancing recommendations.

Religious leaders urged residents to take precautions, saying they have given masks out at synagogues, businesses and schools. The state is increasing testing in the area, and Persichilli encouraged families with sick people to wear masks in the house and keep infected people in a separate room as much as possible.

The state added 796 new cases and four deaths as a rising trend in new infections continued.

“We have a significant amount of cases. And it’s not just in Ocean County, it’s up and down the state,” Murphy said. “We’re still in the thick of the fight.”

Case counts also continue a significant rise in Pennsylvania, which reported 1,161 newly confirmed cases and 19 deaths on Friday. The state’s average number of new daily cases surpassed 1,000 on Friday, a level it had not reached since May.

Philadelphia announced 141 new cases and three deaths. The number of positive tests reported Friday was higher than on recent days.

“We don’t know if this is indicative of a rise, or is just a one-day outlier,” said Matt Rankin, a spokesperson for the Philadelphia Department of Public Health.

Pennsylvania, New Jersey, Delaware, and New York have teamed up in releasing coronavirus-tracking apps, and anyone who downloads their state’s app will be alerted if they are exposed by an app user in another state.

New Jersey launched the app on Thursday, several days after Pennsylvania. About 180,000 of the commonwealth’s 12.8 million residents have downloaded the app and 67,126 of New Jersey’s 8.8 million people have done so, officials in the two states said. It is unclear how many need to download it for the technology to be effective.

COVID Alert PA and COVID Alert NJ will work in conjunction with each other and with the apps in Delaware and New York, Gov. Tom Wolf announced Friday. The app sends users notifications if they come within six feet of someone for 15 minutes or longer who later tests positive for the virus.

“We’re all on the same platform,” Murphy said. “That makes it even more powerful.”

Staff writers Rob Tornoe, Ellie Silverman, Erin McCarthy, and Laura McCrystal contributed to this article.