Viruses are real and you can ‘catch’ them

A claim has recently circulated online falsely suggesting that humans cannot “catch” viruses because “they don’t exist”. The post also mentions “terrain theory” and links to an unrelated article in the Sun about flu, Covid-19 and respiratory syncytial virus (RSV) vaccination.

Health misinformation that spreads at scale can introduce confusion about the causes and treatments of illnesses, and distract from or undermine medical consensus.

Why are people saying viruses don’t exist?

The idea that viruses aren’t real and can’t be spread is sometimes referred to as terrain theory.

Terrain theory is the name given to the belief that illnesses are formed within the body and are caused by things such as what we eat and do.

As we’ve said before, “germ theory”, which states that many human diseases are caused by microscopic organisms, has been conclusively proved in the years since it was first put forward.

Germ theory is well-established and is accepted as scientific fact, and so any theory suggesting it is untrue should be considered with caution.

And while it’s true that not all diseases are caused by such microscopic organisms—some are caused by genetic factors or malnutrition, for example—suggesting humans cannot pass diseases onto one another or “catch” an illness is simply incorrect.

Coronavirus, flu and RSV are real

As we’ve said, the post makes specific reference to an article about coronavirus, flu and RSV.

We can prove that all these viruses do exist, as they’ve been sequenced many times.

And as we’ve written before, the SARS-CoV-2 virus that causes Covid-19 has been isolated and sequenced many times.

Dr Stephen Griffin, a virologist and Associate Professor at Leeds Institute of Medical Research, previously told Full Fact: “SARS-CoV2 has been sampled millions of times over from infected people, including those originally found to be infected in China.” 

Likewise, influenza has been sequenced by health bodies around the world, including the US Centers for Disease Control and Prevention (CDC) and the UK Health Security Agency (UKHSA).

These gene sequences are compiled in databases such as the Global Initiative on Sharing All Influenza Data (GISAID) and GenBank.

RSV has been similarly sequenced thousands of times.