The U.S. has taken the unprecedented step of dropping the number of vaccines it recommends for every child — leaving other immunizations, such as flu shots, open to families to choose but without clear guidance. Officials say the overhaul to the federal vaccine schedule, announced Monday, won't result in any families losing access or insurance coverage for vaccines, but medical experts are slamming the move, saying it could lead to reduced uptake of important vaccinations and increase disease.

A recent study of schoolchildren finds that the youngest students harbor the most germs. Researchers looked at nasal swabs and symptom reports of more than 800 students and staff in Kansas City, Missouri. Kids in pre-kindergarten and elementary school had the highest rates of virus detection compared with older students and staff. The pre-K kids, ages 3 to 5, had the highest rates of actual illness, too. Young children can have up to 10 respiratory viruses as their immune systems are introduced to different infections for the first time. Those viruses include colds, flu and more.

Health Secretary Robert F. Kennedy Jr.'s new vaccine advisers added confusion Friday to this fall's COVID-19 vaccinations. For the first time since the shots were developed, the group has declined to recommend their use — instead leaving the choice up to those who want them. The Food and Drug Administration recently put new restrictions on this year's shots from Pfizer, Moderna, and Novavax, reserving them for people over 65 or younger ones at higher risk. The Centers for Disease Control and Prevention advisers declined to recommend that those people seek a shot but narrowly avoided urging states to require a prescrption for those who want one.