Protests against mandated COVID-19 vaccines pop up across US

Michigan health officials are urging attendees of a recent motorcycle event to get tested after 16 COVID-19 cases were linked to it.

The Michigan Department of Health and Human Services said they are investigating the outbreak that was linked to the Muskegon Bike Time event, which was held from July 15 to 18.

Some individuals were at the event while they were infected, according to the health department.

"Attendees at Bike Time may have been exposed and are urged to get tested based on CDC’s latest guidelines," Dr. Joneigh Khaldun, the chief medical executive and chief deputy for health at MDHHS, said in a statement.

-ABC News' Darren Reynolds and Josh Hoyos

Health officials from eight Bay Area counties, including San Francisco and the city of Berkeley, announced Monday they will be reinstating a mask mandate for all residents for indoor activities.

The new orders go into effect at midnight. The order comes as COVID-19 cases and hospitalizations are on the rise in California, due to the delta variant, according to officials.

"While there may be slight differences between each jurisdictions' orders issued today, they all have one thing in common. A simple step, wearing a mask indoors to provide one more layer of protection for everyone," Dr. Chris Farnitano, the health officer for Contra Costa County, said at a news conference.

In the U.S., 59.72% of counties are reporting high community transmission. Five weeks ago, only 8% of counties were reporting high transmission, according to federal data.

Louisiana now has the highest case rate in the country with more than 600 new cases per 100,000 residents, according to federal data.

Louisiana Gov. John Bel Edwards on Monday reinstated a statewide indoor mask mandate for everyone ages 5 and above.

Louisiana is followed by Florida, Arkansas and Mississippi with 500, 400 and 300 new cases per 100,000 residents respectively.

-ABC News’ Arielle Mitropoulos

Sen. Lindsey Graham, who is vaccinated, said he’s tested positive for COVID-19.

"I started having flu-like symptoms Saturday night and went to the doctor this morning," the Republican senator tweeted Monday. "I feel like I have a sinus infection and at present time I have mild symptoms."

Graham continued, "I am very glad I was vaccinated because without vaccination I am certain I would not feel as well as I do now. My symptoms would be far worse."