BfS: UV radiation is no help against COVID-19

Depiction of a virus

There have been numerous recent reports of a possible link between UV radiation and efforts to stem the coronavirus outbreak. Some people might therefore come up with the idea of exposing themselves to intense UV radiation in order to rid themselves of the coronavirus.

However, what is often not made clear is that these reports only concern the sterility of surfaces or objects, not the destruction of the virus on or in living organisms. The BfS therefore wishes to emphasise that UV radiation is not suitable for curing COVID-19.

Artificial UVC radiation can disinfect surfaces but not people

When people talk about UV radiation in the context of the coronavirus, they mean UVC radiation, which is commonly known to kill viruses and bacteria.

It is possible to generate UVC radiation artificially in order to put its advantages to use: UVC lamps are commonly used for disinfection – for example, at laboratory workplaces that must be kept sterile or in disinfection systems for ponds or other bodies of water. These lamps are also used in the battle against coronavirus – in order to eradicate the pathogen from surfaces in aircraft, for example.

Natural UVC radiation does not reach the Earth's surface

Classification of UV rays according to wavelength bands

UVC radiation also comes from the sun – as do UVA and UVB. But UVC is particularly energy-rich and is completely filtered out by the Earth's atmosphere, such that natural UVC radiation does not reach the Earth's surface – otherwise, it would not have been possible for life to emerge on Earth.

Those under the impression that solar radiation will kill the virus in humans, and therefore cure COVID-19, are mistaken. On the contrary, one possible effect of UV radiation is to suppress the body's immune defences. Therefore, people who are ill should ideally avoid blazing sunshine – regardless of the disease they're suffering from.

Caution: UVC is harmful to humans

Moreover, UVC radiation is harmful to humans, as are UVA and UVB. Under no circumstances should people look into or stand beneath UVC lamps or even hold parts of their body under them. This is because:

• UVC radiation can damage genetic material in a similar manner to UVB radiation and is therefore carcinogenic to humans, as are UVA and UVB. This is true even at lower intensities than those required for disinfection.

• UVC radiation can cause various harmful effects in the eyes and on the skin:

  • Eyes: UVC radiation can damage the surface tissue of the eye. Studies into accidental exposure of the eye to levels in excess of the limit values generally show that ocular symptoms tend to subside within about a week. However, higher levels of exposure can lead to much longer-lasting eye problems.
  • Skin: UVC is primarily absorbed by the stratum corneum, the outermost layer of the human epidermis. The acute effects on the skin, such as erythema (sunburn), are known to be transient phenomena.

There is no threshold in terms of either the radiation intensity or the dose (radiation intensity multiplied by exposure time) of UVC radiation – or indeed of UVB and UVA radiation – below which people are safely protected from the long-term effects on the eyes and skin.