A fully vaccinated Catt Sadler revealed that she has contracted the Delta variant of COVID-19.

"I’m telling you this so that you understand that the pandemic is very much NOT over," the former E! host, 46, warned her Instagram followers Tuesday alongside a photo of herself lying in bed.

"Delta is relentless and highly contagious and grabbed ahold of me even after getting vaccinated," she wrote.

Sadler, who turned off the comments on her post, revealed she contracted the rapidly spreading variant while caring for an unvaccinated person who was sick with it — despite wearing a mask while in their presence.

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"I assumed I would be fine. Well I’m not. I’m one of many breakthrough cases that we are seeing more of each and every day," she wrote. "Two days of a fever now. Head throbbing. Extreme congestion. Even some weird puss coming out of my eye. Serious fatigue; no energy to even leave the bed."

A fully vaccinated Catt Sadler revealed that she has contracted the Delta variant of COVID-19. 

A fully vaccinated Catt Sadler revealed that she has contracted the Delta variant of COVID-19.  (Photo by Toni Anne Barson/WireImage)

The entertainment reporter ended her message by warning people to keep their guards up even if they’re vaccinated.

"I’m no MD but I’m here to remind you that the vaccine isn’t full proof. **Vaccines lessen the likelihood of hospitalization and death but you can still catch this thing," she wrote. "So continue to protect yourselves."

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Although contracting COVID-19 after being fully vaccinated is rare, it is possible and "expected," the Centers for Disease Control says, as the vaccines are not 100 percent effective against the virus.

To read more from the New York Post, click here.