Similarities and differences between influenza and COVID-19

Influenza has caused repeated pandemics throughout human history, the last one in 2009, with a lower mortality impact than that reported in 1918, partly due to the availability of antivirals and a useful vaccine against this new virus within a few months of the pandemic being declared, applied the most vulnerable populations, as well as to intensive care units, and antibiotics administered to manage patients with complicated bacterial superinfections. More recently, in 2019, the COVID-19 pandemic emerged, much more aggressive and lethal than the 2009 influenza pandemic, with greater systemic involvement, vascular and thrombogenic damage, and more sequelae, at a time when there were no useful antivirals or vaccines, but with better care for critically ill patients. Both the influenza virus and SARS-CoV-2 are RNA viruses that primarily affect the respiratory system and require assistance for respiratory failure and the need for mechanical ventilation and critical care. After pandemics, isolated cases of both COVID-19 and influenza continue to occur, but seasonal outbreaks also need to be taken into account to boost immunity with updated vaccines and to emphasize respiratory precautions.