Our internal borders open next week and microbiologist Siouxsie Wiles has a simple message for when things start to become very complicated. She wants everybody to think before they travel because that could save lives. It is widely expected our Covid-19 case numbers will rise sharply around the country when interaction between people escalates from December 15. Siouxsie Wiles is proposing that Aucklanders consider a "stay-cation" this summer. She spoke to Corin Dann.