Transmission route of rhinovirus - the causative agent for common cold. A systematic review.

BACKGROUND: Human rhinoviruses (RVs) are the most common cause of acute respiratory tract illness and upper respiratory tract infections, traditionally defined as 'common colds'. Experimental transmission of RV has been studied for more than 50 years. However, there are divergent results as to whether hands and fomites or aerosols constitute the dominant route of transmission in natural settings.

METHODS: We have systematically reviewed the literature according to the PRISMA 2020 statement. Searches were run in PubMed and Web of Science until August 2022. Inclusion criteria were original studies of relevance for revealing the route of transmission of rhinovirus in humans.

RESULTS: The search yielded 663 results, and 25 studies met the inclusion criteria and were selected for this review. These articles addressing RV transmission routes were assigned to 1 of 3 groups: (1) indirect transmission by fomites and hands, (2) direct transmission via large aerosols (droplets) or small aerosols, or (3) transmission either direct via large aerosols (droplets) or small aerosols and fomite or hands.

CONCLUSIONS: We found low evidence, that transmission via hands and fomite followed by self-inoculation is the dominant transmission route in real-life indoor settings. We found moderate evidence, that airborne transmission either via large aerosols or small aerosols is the major transmission route of rhinovirus transmission in real-life indoor settings. This suggests that the major transmission route of RVs in many indoor settings is through the air (airborne transmission).