A Study to Test Whether BI 767551 Can Prevent COVID-19 in People Who Have Been Exposed to SARS-CoV-2

This study is open to adults living with a person who has tested positive for the coronavirus SARS-CoV-2. People who do not have symptoms of COVID-19 can take part in this study. The study is done to find out whether a medicine called BI 767551 can prevent COVID-19. BI 767551 is an antibody against the coronavirus SARS-CoV-2. Participants are put into 3 groups randomly, which means by chance. * 1 group gets BI 767551 via an inhaler and placebo as an infusion * 1 group gets BI 767551 as an infusion and placebo via an inhaler * 1 group gets placebo both via an inhaler and as an infusion All participants get study medicine once at study start and after 1 week. Placebo inhaler and infusion look like BI 767551 inhaler and infusion but do not contain any medicine. Participants are in the study for about 3 months. During this time, they visit the study site about 10 times. About 7 of the 10 visits can be done at the participant's home. Participants are regularly tested for the coronavirus SARS-CoV-2. The doctors check whether the participants have been infected with the coronavirus and whether they have symptoms. The results are compared between the treatment groups. The doctors check the health of the participants and note any health problems that could have been caused by BI 767551.