24-05-2025
South Dakota urges vigilance as measles cases surge nationwide
May 23—SIOUX FALLS — Measles, once declared eliminated in the United States, is making an unexpected comeback — infecting more than 1,000 people nationwide this year alone.
That's triple the number reported just a year ago. The highly contagious virus is spreading rapidly, especially among unvaccinated children, prompting health officials across the country to issue urgent warnings.
"Measles is one of the most contagious diseases known to humans," explained Dr. Peter Paul Lim, infectious disease specialist with Avera Medical Group. "If you're unvaccinated and exposed, there's a 90% chance you'll catch it — that's 9 out of 10 people."
While South Dakota has not yet seen cases in 2025, health officials say with summer and travel season underway, vigilance is important to help prevent the virus from reaching the state.
"Unfortunately, the vast majority of the cases are occurring among children, individuals less than 20 years of age, and about 96% of infected individuals are unvaccinated or their status of vaccination is unknown," said South Dakota State Epidemiologist Joshua Clayton. "That is really concerning because we have pockets of our country where we have low vaccination rates and measles has found one of those pockets."
So far this year, 14 measles outbreaks have been reported across 31 states, with Texas at the center of the resurgence. Of the 1,046 confirmed cases nationwide, 961 are linked to outbreaks, according to the CDC. Texas alone accounts for 728 cases, making it the hardest-hit state. Other significant outbreaks have been reported in New Mexico, Oklahoma and Kansas.
"This kind of transmission is something not seen in recent years," said South Dakota Department of Health Vaccine Preventable Disease Epidemiologist Sara Bowman.
The disease has also spread to several states surrounding South Dakota, including North Dakota 11 — its first measles cases since 2011. Minnesota has seen two cases of Measles so far this year. Iowa and Nebraska currently have zero cases. South Dakota last reported a case in July 2024, involving an adult who contracted the virus while traveling internationally.
Nearly all infections — about 96% — occur in people who are unvaccinated or whose vaccination status is unknown. Dr. Peter Paul Lim, an infectious disease specialist with Avera Medical Group, pointed to Gaines County, Texas — where this year's largest outbreak began — as an example.
"There was a vaccination rate of only 82%," he said. "This is fertile ground for measles to spread quickly if it gets a toehold."
The Centers for Disease Control and Prevention (CDC) notes measles spreads through airborne droplets and can linger in the air or on surfaces for up to two hours after an infected person leaves. Symptoms typically appear 10 to 14 days after exposure and begin with high fever, cough, runny nose and red eyes, followed by a distinctive rash spreading from the hairline down.
"So you can have a person who is infected with measles, and if they spent, time in an area or even simply passed through that area, whether it be an airport, or a mall, or things like that, measles can stay in the environment, in the air for up to about 2 hours after that person has passed through," Clayton said. "And it is so contagious that about 9 out of 10 people who come near a person with measles and are not protected by vaccination will also become infected."
According to health experts, measles elimination in the U.S. — achieved in 2000 — relied on maintaining high immunization coverage. The recent decline in vaccination rates has created conditions for localized outbreaks, particularly in areas where rates have dropped below 93%.
While South Dakota has generally maintained strong immunization coverage, Clayton noted that MMR vaccination rates have declined over time and now lag slightly behind the national average. Currently, 91% of kindergartners in the state are vaccinated, compared to 93% nationwide.
However, coverage varies widely: only 25 of the state's 66 counties meet the 95% threshold needed for community protection, and in some areas, rates have dropped as low as 60% — well below the level required to prevent outbreaks.
"Some counties are doing fantastic, but others are a lot lower," said Dr. Ashley Sands, pediatric specialist at Sanford Health.
The measles, mumps, and rubella (MMR) vaccine remains the best protection. After two doses, it is about 97% effective and provides long-lasting immunity. Children typically receive the first dose between 12 and 15 months of age, and a second dose between ages 4 and 6. According to Sands, the vaccine used today remains the same formulation introduced in the 1970s and offers long-lasting protection.
"The vaccine you received decades ago still protects you today because the measles virus doesn't mutate like the flu or COVID," Sands said.
So far in 2025, three measles-related deaths have been reported, all in unvaccinated individuals. Nationwide, about 13% of cases have required hospitalization.
Though South Dakota currently has no confirmed cases this year, health officials stress that prevention and awareness are key.
"We know that our tools for prevention of measles are much more effective than our treatments," said South Dakota Department of Health Medical Director Denise Hanisch. "Education is key. We need a high level of awareness when it comes to measles."
