Vaccine opponents, a scattered though potent force, have been gearing up in recent weeks to fight state health officials who are pushing for new immunization rules for babies and young children. This latest vaccine skirmish centers on proposals to require that young children in child care centers or preschool get vaccinated against both the flu and pneumonia. The shots would be for children over 6 months old and would include the pneumococcal conjugate vaccine (PCV7), and the influenza vaccine. Health officials said the mandates, not yet final, would prevent as many as 300 hospitalizations each year -- and possibly several...