About 60 Jackson County students were sent home from school Wednesday for failing to have their immunizations up to date, but many had returned to their classrooms Thursday after getting the required injections.

About 60 Jackson County students were sent home from school Wednesday for failing to have their immunizations up to date, but many had returned to their classrooms Thursday after getting the required injections.

Oregon law requires children to be vaccinated against a number of communicable diseases unless their parents request an exemption. Wednesday was "exclusion day," the deadline for bringing immunizations current, and students who could not produce proof of valid vaccinations were sent home.

Public health officials had sent notification letters to parents of 327 students who were either missing some immunizations and 100 who had no immunization records. By Wednesday's deadline, only 57 children had incomplete vaccination records, and eight had no record of immunization, said Viki Brown, Jackson County's director of public health services.

Immunization remains one of the most effective tools in controlling infectious disease. More than 25 childhood vaccinations are doled out, mostly before the age of 2, for diseases including diphtheria, pertussis (whooping cough), tetanus, polio, measles, mumps, rubella and hepatitis B.

In recent years, some parents have resisted immunization because they believe mercury-based preservatives in vaccines have contributed to a rise in the incidence of autism in children. Mercury preservatives were removed from vaccines in 2001, but autism rates have not declined and the fear of vaccines among some parents remains.

The number of children who receive notification letters has dropped steadily since 2005, when public health officials sent 1,179 letters. Carol Irwin, Jackson County's immunization coordinator, said the state's computerized immunization database, "Oregon Immunization ALERT," has helped parents and school administrators keep track of children's immunizations.

The ALERT site collects data from medical providers, creating a consolidated record for children who may get their immunizations from different sources. Schools are using the database, too, Irwin said, to keep track of their pupils without having to bother parents.

The site has security to protect parents' and children's privacy and the confidentiality of their medical records.

Irwin said she expects a spike in the number of letters next year as the state adds new immunization requirements. Preschoolers will be required to be immunized against hepatitis A, and a booster for tetanus, diphtheria and pertussis (Tdap) will be required in seventh grade.

Researchers have concluded that the pertussis vaccines given in early childhood gradually lose efficacy around early adolescence, and many youngsters in that age group have been infected during recent pertussis outbreaks. Public health officials recommend that adults receive a pertussis booster when they get a tetanus booster.

Reach reporter Bill Kettler at 776-4492 or e-mail bkettler@mailtribune.com