As I write, in late July 2021, Covid-19 infection rates are increasing rapidly, at the same time as restrictions are being eased, and people from all walks of life are becoming increasingly nervous about being infected. This nervousness is, quite understandably, shared by church congregations, and some are questioning whether it is actually safe to come to church in the current circumstances. Is it therefore actually possibly to be a bit more precise about what the actual risk of attending church might be? The answer is a qualified, yes, it is possible, very approximately, to calculate the risk of infection at church services, and, in this article, I will describe the risks of attending church for different scenarios, based on the current situation at St. Michael’s church in Lichfield, where I serve as a minister.
The method I will use is that developed by Prof Jose-Luis Jimenez at the University of Colorado – Boulder in the USA. This is a simple spreadsheet-based model of Covid transmission and infection using the latest scientific knowledge and which can be used in a variety of situations – residential homes, shops, public transport and places of worship for example. It is more fully described here. It is based on aerosol transmission of the virus, which is now regarded as the main way in which the virus is transmitted, particularly if simple hygiene methods are followed, such as regular cleaning of services and washing of hands, to reduce the risk of picking up the virus by touch. Prof Jimenez would be the first to admit that the method is very approximate and comes with lots of uncertainties, not least because the understanding of the way in which infected people emit the virus is at the moment poorly understood. Nonetheless it does give a rough indication of risk.
The situation I have looked at is effectively the current practice in St. Michael’s in Lichfield – a large, fairly poorly ventilated area, with a congregation of about 60 and a choir of 6. Social distancing is assumed, together with everyone wearing masks and only the choir singing, for a one-hour service, with the current community infection rate of about one in a hundred people being infected with Covid at any one time. 80% of the congregation are assumed to be double vaccinated. Plugging this lot into the spreadsheet gives a risk of any one member of the congregation being infected with the virus at a particular service of 1 in 26,700. To give some perspective, the risk of being involved in a road vehicle accident in Britain in the week following the service is 1 in 22,000. Thus, attending a service at St. Michael’s with the current practice is very safe indeed, even allowing for the very approximate nature of the calculations – we are all likely to be in much more hazardous situations at other times in the week.
As restrictions ease, churches across the country are considering easing their own restrictions, and Jimenez’s spreadsheet gives a way of how this might change the risk. Again, for St Michael’s, having 100 people in the congregation in church as opposed to 60 (and reducing social distancing) increases the risk to 1 in 17,500. Doing away with masks as well increases the risk further to 1 in 6,100. This is a big jump, as masks both restrict the spread of the virus from those who are infected, and also give some protection to those who aren’t. Taking the next step and letting the congregation sing hymns increases the risk to 1 in 2500. This is because singing, or speaking loudly, increases the breathing rate and allows more virus to be both exhaled and inhaled. As an interim step, should we keep social distancing and mask wearing but allow congregational singing with masks on, the risk of infection comes out as 1 in 10,200.
How these results should be interpreted is of course a matter for the individual. I personally would find a risk of 1 in 5000 acceptable but would begin to get a bit twitchy if the risk were as high as 1 in 1000. Importantly though it should be remembered that the risks are more or less proportional to the number of infected in the general population. So as the community infection rate drops, as one hopes it will, the risk decreases. For example, if the community infection rate was 1 in 500, the risk of being infected at a church service with no social distancing, no masks and with singing, falls to 1 in 12,500, which I, for one, would regard as very acceptable and quite safe.
Engineering, history and ecclesiology 