Social media users have reported suffering ill health effects after coming into contact with — fog.

The phenomenon has been documented in viral TikTok videos, with one man claiming fog that rolled in around Christmastime was causing sore throats and flu-like symptoms.

“Anyone else notice since this fog arrived on Christmas Day, you have sore throat, you started to feel lethargic, you lost your appetite, you felt flu-ey, you couldn’t do anything, you didn’t have any energy, sweat, couldn’t sleep,” the TikTok user documented, adding he believed the fog contained chemicals intended to make people sick.

The man concluded by asking fellow TikTok users if they’ve experienced any symptoms.

“Not going to lie I legit got a sore throat after the fog,” one user responded.

“Lots of headaches since the fog,” another stated.

After numerous commenters reported feeling similar negative health effects, the man later returned with an update confirming “Fogvid24” was indeed real, and that it’s not centralized to one location but appears to be global.

“We’ve got people in Kentucky, we’ve got people in Sweden, we’ve got people in Finland — all reporting the same thing. The fog has made them sick,” the man revealed.

Another TikTok user characterized the fog as a “chemical fog” and described it smelled and tasted like sulfur.

On X, another user described driving through a “chemical fog,” remarking they believed normal fog should produce water droplets on their windshield.

Another X user claimed he “got rapidly ill with cold/flu symptoms and it was after brief exposure to fog.”

Are the “Fogvid” claims valid? Have you experienced similar symptoms after coming into contact with fog?