U.S. kindergarten vaccination rates have declined again, with exemptions reaching a record high. Federal data released Monday shows 4.2% of children are exempted from vaccine requirements, up from 3.6% the previous year. This marks the fourth consecutive year of rising exemption rates, mostly due to nonmedical reasons. Experts blame confusion in vaccination recommendations. The CDC reports a slight drop in measles-mumps-rubella shots, and that vaccination rates for polio and other diseases also are falling. The U.S. is experiencing its worst measles year since 1991. Some state health officials are urging parents to vaccinate their children as schools can be hot spots for outbreaks.