We've been warned the pandemic should be seen as a "wake up call".
Professor Niall Moyna says it's clear Covid has a harsher effect on people with pre-existing conditions, including those due to poor diet, smoking and a lack of exercise.
Speaking on The Joe Finnegan Show today, the Monaghan native said it's fantastic to see people taking up walking or running as exercise during the pandemic.
He says research shows that elderly people in particular have a better immune response if they remain physically active as they get older.
But Professor Moyna has warned many people need to change how they're living their lives: