In the present paper, we have analysed the role of age and sex in the fatal outcome of COVID-19, as there are conflicting results in the literature. As such, we have answered three controversial questions regarding this aspect of the COVID-19 pandemic: (1) Have women been more resilient than men? (2) Did centenarians die less than the remaining older people? (3) Were older centenarians more resistant to SARS-CoV-2 than younger centenarians? The literature review demonstrated that: (1) it is women who are more resilient, in agreement with data showing that women live longer than men even during severe famines and epidemics; however, there are conflicting data regarding centenarian men; (2) centenarians overall did not die less than remaining older people, likely linked to their frailty; (3) in the first pandemic wave of 2020, centenarians > 101 years old (i.e., born before 1919), but not "younger centenarians", have been more resilient to COVID-19 and this may be related to the 1918 Spanish flu epidemic, although it is unclear what the mechanisms might be involved.
Keywords: COVID-19; Spanish flu; age; immune responses; longevity; mortality; narrative review; sex.