  Interactions between COVID-19 and other pathogens may change their dynamics.
Specifically, this may hinder the modelling of empirical data when the symptoms
of both infections are hard to distinguish. We introduce a model coupling the
dynamics of COVID-19 and seasonal influenza, simulating cooperation,
competition and asymmetric interactions. We find that the coupling synchronizes
both infections, with a strong influence on the dynamics of influenza, reducing
its time extent to a half.
