The dangers of catching COVID again and again

COVID infections are on the rise again, thanks to the latest sub-variant of Omicron.  And if you think just because you've had COVID already you won't get it a second time, think again: even if you're vaccinated, your immunity only lasts a few months, and reinfection numbers are climbing.  Today, epidemiologist Nancy Baxter on the health dangers associated with having COVID-19 more than once, and why we should all be doing everything to avoid it.  Featured: Professor Nancy Baxter, epidemiologist and head of school, Melbourne School of Population and Global Health