Utah reports more than 600 measles cases as outbreak spreads across US

Utah has emerged as a major center of measles infections in the US, as an outbreak that has been building for some time continues to expand.

State officials reported a total of 602 measles cases on Wednesday tied to an outbreak that started last year and is still ongoing, including 19 newly identified infections, according to the Center for Infectious Disease Research and Policy (Cidrap). Recent exposures have been reported at several preschools and elementary schools.

About one-third of those infected have experienced symptoms severe enough to require visits to emergency rooms, reported the New York Times, largely due to intense dehydration from vomiting and diarrhea.

Out of the 602 total cases, 405 have occurred since the beginning of this year, with 75 reported in just the last three weeks. So far, 49 individuals have needed hospitalization. A significant majority of those infected – 513 people, or 85% – were not vaccinated against measles.

Over the past year, large measles outbreaks have appeared in multiple parts of the country, including Texas and South Carolina. However, unlike many previous outbreaks – which were often linked to close-knit religious communities – the spread in Utah appears to be occurring more broadly across the general population.

Although about 90% of Utah residents are vaccinated, this still leaves enough unvaccinated individuals for the virus to circulate. Typically, about 95% vaccination coverage is needed to achieve “herd immunity”, which helps protect those who are not immunized.

Despite the outbreak, state lawmakers introduced a bill earlier this year that would have made it easier for families to opt out of school vaccination requirements. Although the proposal did not pass, its introduction in the midst of an active outbreak highlighted ongoing tensions between public health experts and the anti-vaccine movement.

The outbreak originally began in Texas more than a year ago and has since spread to most states across the country, marking the end of the period when measles was considered eliminated in the US. Most cases have occurred in children, many of whom had not received the measles, mumps and rubella (MMR) vaccine. Infants under one year old and children with certain health conditions remain especially at risk, even in communities with high vaccination rates.

The situation has also been further complicated by the spread of misinformation. Robert F Kennedy Jr, secretary of the US Department of Health and Human Services and a longtime vaccine critic, has described measles vaccination as a personal choice and has promoted treatments that have not been proven effective.