Guidance from doctors in Germany includes the following effects of wearing a face covering on transmission. This is based on two people in close conversation, with one on them carrying the virus.
1. Neither wear a face covering: Chance of transmission ~90%
2. Only the uninfected person wears a face covering: Chance of transmission ~30%.
3. Only the infected person wears a face covering: Chance of transmission ~5%.
4. Both wear a face covering: Chance of transmission ~1.5%
A graphic is available HERE.
We can offer some guidance on safe use of churches allowing from covid-19 variants of our YouTube Channel 'Stewarding precious Earth'. This includes guidance on ventilation.,on covid safety and on use of carbon dioxide meters; a procedure for using a meter and improving air quality is provided on this page.
The use of face masks, ventilation and air purifiers is considered in a document on this page. similarly a video about this is also available on YouTube.
We have updated an estimation of risks due to the more infectious Omicron variant. Our guidance does seem to remain valid and adopting high quality facemasks is even more important.
Updated January 10, 2022.