why infections are rising – and how booster shots still help
- Written by Michael Plank, Professor in Applied Mathematics, University of Canterbury
Getty ImagesSix years after COVID-19 first reached New Zealand, the country is experiencing its ninth wave of infections.
But the virus we are living with today behaves very differently from the one that caused the global emergency in 2020–22.
Large outbreaks can still occur, but thanks to widespread immunity built through vaccination and...





