Recent studies show a drop in effectiveness for COVID-19 vaccines, but the lack of information about how severe breakthrough cases were has sparked a debate about whether booster shots are necessary. Watch The National live on YouTube Sunday-Friday at 9…

New research suggests that taking antioxidant vitamins and supplements during cancer treatment could be harmful and impact the effectiveness of chemotherapy. Welcome to The National, the flagship nightly newscast of CBC News »»» Subscribe to The National to watch more…