*2.3. Design and Procedure*

Our research was an ex post-facto cross-sectional study conducted using an online survey questionnaire. The ethics approval was obtained from the Ethics Committee of the Jesuit University Ignatianum in Krakow in accordance with the principles embodied in the Declaration of Helsinki. The participants explicitly expressed their consent by checking a box after reading the instruction which explained the aims of the study, data processing, and data anonymity.

First, a survey questionnaire was developed in Google Forms, which consisted of two parts. The first one included sociodemographic variables and data related to COVID-19 infection. The second part contained standardized research tools. The study was conducted using the "snowball" method (via social media). Participation in the study was voluntary and anonymous, and the participants could resign from filling in and submitting their responses at any time. Filling in the survey took approximately 20 min.

The study was conducted from 1 December 2020 to 1 January 2021. It was a special month, because at that time, the number of new coronavirus cases and COVID-related deaths in Poland was very high (9.105 new infections and 449 deaths were recorded on 1 December 2020) [31], which resulted in tightened government restrictions. It should also be underlined that, for many Poles, December is a month of spiritual preparation for Christmas, and that restrictions limited both family contacts and active participation in religious ceremonies.
