Does cystic fibrosis constitute an advantage in COVID-19 infection?

The Veneto region is one of the most affected Italian regions by COVID-19. Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD), may constitute a risk factor in COVID-19. Moreover, respiratory viruses were generally associated with severe pulmonary impairment in cystic fibrosis (CF). We would have therefore expected numerous cases of severe COVID-19 among the CF population. Surprisingly, we found that CF patients were significantly protected against infection by SARS-CoV-2. We discussed this aspect formulating some reasonable theories.