Arizona's largest measles outbreak in more than 30 years continues to grow.
Over the past six weeks, 42 cases of measles have been confirmed in the Mohave County town of Colorado City, according to the Arizona Department of Health Services. Another 21 cases have been reported recently in neighboring communities in Utah, according to the Utah Department of Health and Human Services.
Colorado City is a town of about 2,500 people on the Arizona-Utah border. Many residents of the area are members of the Mormon-offshoot polygamist sect known as FLDS, or the Fundamentalist Church of Jesus Christ of Latter-Day Saints. The community has very low vaccination rates.
One Colorado City elementary school last year reported a kindergarten measles vaccination rate of just 7% — the lowest rate reported by any school in the state, records from the Arizona Department of Health Services show. The other school in the town reported a 40% kindergarten MMR vaccination rate last year.
The MMR vaccine is highly effective at preventing measles. According to the Centers for Disease Control and Prevention, two doses of the vaccine are 97% effective at blocking the virus. But because measles is one of the most contagious viruses known, medical experts say about 95% of a population needs to be immunized to prevent it from spreading.
