HONOLULU (KHON2) -- As Hawaii's measles vaccination rate continues to decline, Department of Health officials are expanding efforts to protect the islands from a measles outbreak. The DOH said at least 95% of Hawaii's population must be vaccinated to prevent an outbreak, otherwise known as 'herd immunity.' Two Oahu hospitals receive $10M in grants to expand access to critical cancer care In hopes of encouraging more vaccinations, DOH officials sent a letter to parents and guardians of Hawaii students, especially those who attend schools with low immunization rates. The letter outlines DOH's emergency rule, which states that children with a religious exemption can receive the MMR (measles, mumps, rubella) vaccine. Students can also be exempt from other vaccines and continue to attend school. The emergency rule is effective for the next four months. Download the free KHON2 app for iOS or Android to stay informed on the latest news Pediatrician and state epidemiologist Dr. Sarah Kemble emphasized the need for vaccination as measles is a serious and sometimes fatal disease for keiki. "At the rate it’s spreading, it could easily reach Hawaiʻi on the next plane. The MMR vaccine is our best defense against the measles virus," Dr. Kemble said. Parents are encouraged to vaccinate their children immediately. If a measles outbreak were to occur, the department said children without an MMR vaccine may be prohibited from attending school. All updates to a child's vaccination record should be reported to their school. Check out more news from around Hawaii The DOH is looking to hold on-site vaccination clinics. In the meantime, parents and staff can access vaccines through the child's healthcare provider or a local community clinic. ...read more read less