How are Hep V vamps killing so many people who are 안전한, 안전 in their homes?

Question: assuming hep-v vamps need an invitation before entering a human's house, how are the committing mass murder? From the looks of it they aren't sabotaging food, water, 또는 air supply. They aren't burning houses down. Why wouldn't people be 안전한, 안전 in their homes until sun up?