Close-up camera shots of face masks and COVID-19 test swabs do not show living microscopic worms, but synthetic fibres moving due to static electricity or moisture.

One clip has racked up thousands of views across Instagram (here) and Facebook (here , here) with the caption: “This is probably the best video I've seen of the alive fibres on swabs. There is absolutely no denying they are alive. The last 3 mins of the video show the fibres burrowing into a pig's brains.”

The clip shows someone pulling apart the end of a COVID-19 testing swab, placing the fibres next to various objects (a plastic rod, a garden stick, metal tweezers, and an alleged pig brain) and demonstrating their movements.

Other videos were said to capture a cotton bud (here) and a makeup remover pad (here) “eating some bacon”, while another showed cotton bud fibres moving seemingly on their own (here).

However, the fibres are not alive. Reuters presented the videos to experts at the Meedan Health Desk (health-desk.org/), who explained that the movement was caused by static electricity.

“Every object we encounter on this planet is holding an electric "charge" — a balance of electricity that's unique to that object,” they wrote in an explainer (here).

The way an item is charged — positive, negative or neutral — determines how it interacts with the world. Opposite charges attract, for instance. Static electricity is caused by an imbalance of negative and positive charges that build up on an object’s surface until they are released.

A classic example is rubbing a balloon on straight hair, creating an imbalance of charges that causes the hair to move around “seemingly magically”, they said. This phenomenon is also explained in a BBC explainer for early secondary school pupils (here).

COVID-19 testing swabs are typically made from synthetic fibres such as polyester, rayon, viscose and nylon, which rub against each other and create extra static, the Meedan experts added.

Pulling the fibres apart makes them more negatively charged – therefore creating more static –causing them to repel and move around when placed near other negatively-charged objects, like meat. The testing swab fibres also move when placed near metal (positively charged) or wood (neutral) because opposites attract.

Other posts claim to show wiggling worms in face masks. A woman looked at a mask under a microscope and shared photos of dark, thin shapes, writing that she was shocked and “won’t ever stick one of these on my face or near me!” (here).

In a follow-up video, she puts water on the mask to “activate” the worms and says: “It’s moving, it’s doing little wiggles, I just can’t believe it.” (here).

Meedan’s scientists had an explanation for this, too. “Similar to swabs, there are also no living fibres or worms in surgical face masks,” they said (here). Surgical face masks are typically made from fabrics derived from safe materials called thermoplastic polymers, such as polypropylene.

Any strands in face masks that appear to be moving on their own under a microscope are regular, textile fibres that make up a large portion of house dust, they explain. The movement is caused by static or moisture, the latter owing to tiny air currents in the water that can’t be felt by humans, or water evaporation that makes the fibres change shape.

The Meedan scientists added that the false claims have “no scientific basis” and that the experiments conducted in the videos were not conducted “with scientific rigor”.

False. Face masks and COVID-19 test swabs are safe to use. They are not made of live fibres or microscopic worms, but synthetic materials that sometimes can be seen to move under a microscope due to static or moisture.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work here .

Our Standards: The Thomson Reuters Trust Principles.

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