Chris Rock says he has COVID-19: 'Trust me, you don't want this'

NEW YORK, NEW YORK - MAY 28: Actor Chris Rock joins New York Governor Andrew Cuomo and Rosie Perez at a press conference where the two performers helped to promote coronavirus testing, social distancing and the use of a face mask on May 28, 2020 in N

Chris Rock on Sunday said he has been diagnosed with COVID-19 and sent a message to anyone still on the fence: "Get vaccinated."

The 56-year-old comedian wrote on Twitter: "Hey guys I just found out I have COVID, trust me you don’t want this. Get vaccinated."

Rock has previously said he was vaccinated. Appearing on "The Tonight Show" in May, he called himself "Two-shots Rock" before clarifying that he received the one-shot Johnson & Johnson vaccine.

"That’s the food stamps of vaccines," he joked.

"You know, I skipped the line. I didn’t care. I used my celebrity, Jimmy," he told host Jimmy Fallon. "I was like, ‘Step aside, Betty White. Step aside, old people. ... I did ‘Pootie Tang.’ Let me on the front of the line.'"

Rock joins other celebrities who have publicly announced breakthrough coronavirus diagnoses such as Melissa Joan Hart and Wendy Williams.

A breakthrough case, while rare, is when a person who is fully vaccinated against the novel coronavirus still gets infected. 

The CDC reported in June that it had tracked roughly 4,115 patients with COVID-19 vaccine breakthrough cases who were hospitalized or died. Of those cases, 26% of hospitalizations were reported as asymptomatic or not related to COVID-19, and 19% of the 750 fatalities were reported as asymptomatic or not related to COVID-19. 

RELATED: CDC: Less than 1% of breakthrough COVID-19 cases led to hospitalization or death

In studies, the two-dose COVID-19 vaccines by Pfizer and Moderna were around 95% effective at preventing illness, while the one-shot Johnson & Johnson shot was 72% effective, though direct comparisons are difficult. So while the vaccines are very good at protecting us from the virus, it’s still possible to get infected with mild or no symptoms, or even to get very sick.

If you do end up getting sick despite vaccination, experts say the shots help reduce the severity of the illness — the main reason to get vaccinated.

But the understanding of how vaccinated people who are infected might spread the virus to others is changing.

Previously, health officials believed vaccinated people who get breakthrough infections were unlikely to spread the virus. But with the more contagious delta variant that is now dominant, the U.S. Centers for Disease Control and Prevention said new data shows people who get infected could carry enough virus in their noses and throats to spread it to others.

The agency updated its guidance in July to say vaccinated people should go back to wearing masks indoors in areas where the virus is surging. 

"It is concerning enough that we feel like we have to act," Dr. Rochelle Walensky, director of the CDC, said in July. 

Still, health experts say the vaccines provide strong protection against serious illness. In the U.S., people who weren’t vaccinated make up nearly all hospitalizations and deaths from COVID-19. 

This story was reported from Detroit. The Associated Press and FOX News contributed.