All students entering Utah schools next fall must prove they have received two doses of the measles, mumps and rubella vaccine, and kindergartners must be immunized against hepatitis B.

Utah is joining most other states in requiring the additional immunizations, said Christine Perfili, acting manager of the state's immunization program.Most physicians have been recommending the additional shots for years. "It's been recommended by the American Academy of Pediatrics for a while," said Suzanne Holbrook, a pediatrician at Nightime Pediatrics in Murray.

The state has required a second MMR dose for students entering kindergarten since July 1992 and is extending that to all students through 12th grade, Perfili said. A second dose has proved to be more effective than a single dose in protecting against infection.

The federal Centers for Disease Control and Prevention since 1991 has recommended hepatitis B shots for newborns.

Hepatitis B is spread by the transfer of infected blood and bodily fluids through unprotected sex or intravenous drug use. Measles is spread by breathing in airborne droplets of moisture coughed out by an infected person.

Of the two, hepatitis B is more dangerous. Once infected, a person never gets rid of the virus. It affects the liver, sometimes inflicting so much damage an organ transplant is needed, said Holbrook.

The shots are required by July 1, and children will have to prove they are up to date on their immunizations upon entering school. Other immunizations required by the state are: diphtheria, tetanus (lockjaw), pertussis (whooping cough), polio, and haemophilus influenza b (hib).

Parents who for personal or religious reasons don't want their children vaccinated can get an exemption.