The median R value for seasonal influenza(aka flu) was 1.28 (IQR: 1.19–1.37), whereas the R rate for COVID without any protection is much higher. It means people staying at home, reducing visits and social distancing might be enough to lower the R rate below one for influenza, however, not necessarily for COVID as the R rate is higher.

https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471...