When Tricia Andersen has a break from her job at a fabric store, she goes online. Not to check Facebook or Twitter but to hunt for vaccine appointments.“Anytime I have a free moment, I pull out my phone,” said the 47-year-old mom from Cedar Rapids. “I’ve got about seven links I’m checking two to three times a day to see if anything pops up.”So far, she’s scored appointments for her parents, in-laws, husband, daughter and herself — following guidelines established by the state.