"Ever since the federal government authorized the coronavirus vaccine for children 5 through 11 nearly three months ago, Mr. Kip has been calling the school’s parents, texting, nagging, cajoling daily. Acting as a vaccine advocate — a job usually handled by medical professionals and public health officials — has become central to his role as an educator. “The vaccine is the most important thing happening this year to keep kids in school,” Mr. Kiplinger said.'