This is a protocol for a Cochrane Review (diagnostic). The objectives are as follows:

• To assess the diagnostic test accuracy of eNoses to screen for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in public places, such as airports.

• To assess the diagnostic test accuracy of sniffer animals, and more specifically dogs, to screen for SARS-CoV-2 infection in public places, such as airports.

• To assess the diagnostic test accuracy of eNoses for SARS-CoV-2 infection or COVID-19 in symptomatic people presenting in the community, or in secondary care.

• To assess the diagnostic test accuracy of sniffer animals, and more specifically dogs, for SARS-CoV-2 infection or COVID-19 in symptomatic people presenting in the community, or in secondary care.

If sufficient data are available, we will investigate the accuracy (either by stratified analysis, or by subgroup analysis) according to specific eNose technology or animal, and according to whether those who are tested are symptomatic or not. We will also investigate whether eNose brand, reference standard, and healthcare setting are associated with differences in diagnostic test accuracy.