DENVER — It’s still too early to tell whether Colorado will be added to the growing list of measles outbreaks across the country, but the state’s first case in 15 months “is an excellent bellwether” for parents to consider vaccination, state health officials said Tuesday, even as the nation’s top health official continues to tout vitamin A as an alternative against the highly contagious disease.
The advice from state health officials came a day after Colorado confirmed its first measles case since December 2023 in an unvaccinated patient in Pueblo who contracted the virus after traveling to a region of Mexico which is currently experiencing an outbreak.
The unidentified person could have exposed others at the Southwest Deli and Cafe (1873 S. Pueblo Blvd.) between March 17 and March 21, as well as patients and staff who were at the Southern Colorado Clinic (109 South Burlington Drive) between 3:30 p.m. and 6 p.m. on March 22, according to state health officials.
Describing it as the “most infectious disease that we know of,” state epidemiologist Dr. Rachel Herlihy said measles will infect about 9 out of every 10 people who encounter someone who is contagious if they don’t have immunity against the virus – even if they’re not in the same room, as measles spreads through the air and can remain airborne for up to two hours. People most at risk for severe complications for measles are children and infants too young to be vaccinated, she said.
The good news, Herlihy said, is that “we have a highly effective vaccine, the MMR vaccine, which is 97% effective at preventing measles infection and provides lifelong immunity.”
Despite its high efficacy, the U.S. still has pockets where vaccination rates aren’t as high as they should be, something health experts say is the main factor driving this year’s multi-state outbreak.
Health experts nationwide have also expressed concerns that claims made by Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. about the use of vitamin A to treat measles could be adding fuel to the fire.
What’s the role of vitamin A as a treatment for measles?
While vitamin A does have a role in treating measles cases, “it’s really important to note that that limited role for vitamin A in treatment is not preventative,” Herlihy said. “For that, we really need to rely on vaccination.”
Though “there is limited evidence that does support the role of vitamin A treatment” to improve the outcomes of hospitalized children or children with more severe disease due to measles, Herlihy warned that vitamin A should be given under the supervision of a healthcare provider due to the potential of vitamin A toxicity, as has been recently reported in Texas.
Taking too much vitamin A can result in intracranial pressure, drowsiness, abdominal pain, nausea, vomiting, changes in the skin, hair and nails, as well as liver damage and, in pregnant women, it can lead to birth defects, according to the Merck Manual, a medical reference publication.
The claim by RFK Jr. that measles can be treated with vitamin A supplementation likely came from a paper published in early 2017 by the World Health Organization (WHO), which advised member states to administer the vitamin “in all cases of severe measles.”
Complications from measles, however, “are more likely in children who are malnourished, especially those without enough vitamin A or with a weak immune system from HIV or other diseases,” according to the WHO.
Vitamin A deficiencies are uncommon in the U.S. and have been labeled as “rare,” with an estimated 0.3% of the U.S. population suffering from deficiencies of this particular vitamin as of 2013, per a report from the National Institutes of Health (NIH) last updated in 2023.
“No one should be giving vitamin A to another person without the input of a healthcare provider. That evidence, as Dr. Herlihy said, is limited, and it's limited to very sick, younger children,” said Dr. Ned Calonge, the chief medical officer for the Colorado Department of Public Health and Environment (CDPHE) during Tuesday’s news conference.
Will other cases pop up in Colorado? It depends on who was exposed
It will take a couple of weeks for state health officials to know whether Colorado is experiencing a measles outbreak, as symptoms of measles typically begin seven to 14 days after exposure but may take up to 21 days to appear, according to Herlihy.
Those symptoms can be anything from a fever, a cough, a runny nose, and red, watery eyes that develop into a rash that starts on the face and then spreads to the rest of the body about three to five days after symptoms first start. A person with measles is contagious four days before and four days after the rash appears, Herlihy said.
“That means that people may have measles but may actually think they have something more like a cold or the flu or COVID and potentially spread that virus to other people before they know they have the illness,” she said.
While most people recover within two or three weeks after contracting the virus, unvaccinated people run the risk of complications from the disease, including ear infections, seizures, pneumonia, brain damage and ultimately, death — as has happened in Texas and possibly, New Mexico.
People in Pueblo concerned about potential exposure to measles should call their healthcare provider before trying to seek treatment to avoid other people from becoming potentially infected with the virus, Calonge said.
If you do not have a health care provider, you are asked to call an urgent care center or emergency department. For additional information about measles, call the free helpline CO-HELP at (303) 389-1687 (toll-free: 1-877-462-2911).
- Denver7 is keeping you informed with expert opinion on this subject. On Tuesday, Denver7 anchors Jessica Porter and Shannon Ogden sat down with Dr. Michelle Barron, the senior medical director of infection prevention and control for UCHealth, who broke down the potential spread of the virus in the video player below
In Pueblo County, where Colorado reported the case that's likely linked to the outbreaks happening in Texas and New Mexico, data shows vaccination rates for the MMR vaccine among school-aged children were around 95% in the city and county, according to Randy Evetts, the director of Pueblo County Public Health (PCPH).
That rate is much lower among kindergarteners in Pueblo proper, where vaccination rates were around 84% during the previous academic year, Evetts said. In surrounding counties, those rates were higher – at 92%.
Statewide, vaccination rates depend on the group you’re looking at, according to Herlihy. Data from the CDPHE shows Kindergarten vaccination rates were about 88%, with that number going up to about 94% for children in the K-12 age group. Though higher, that number is still well below the 95% herd immunity threshold needed to prevent a rise in cases.
“So, statewide, we are falling short of that. That does mean that Colorado is potentially at risk for outbreaks,” Herlihy said.
- The interactive map below from the CDPHE shows the immunization data for the MMR vaccines across all Colorado school districts. Shades of yellow and red show districts whose vaccination status has fallen below the herd immunity threshold. Have problems viewing the map? Click here to access it directly from the CDPHE website.
Who should get vaccinated for measles?
Most people likely got vaccinated when they were about a year old with two doses of the MMR vaccine and are considered fully protected against the disease, but Herlihy said there is a small group of individuals vaccinated before 1968 with an earlier version of the vaccine that wasn’t as effective, and those people may need an additional dose of the vaccine.
If you have children that are less than a year old and are considering traveling internationally or to areas where there are ongoing measles outbreaks, “certainly, I think it is important for folks to be talking to their healthcare provider about their concerns and thinking about that option for early vaccination, especially if we were to see more cases occur in state,” Herlihy said.
Because Colorado isn’t currently experiencing an outbreak (which is defined as three or more measles cases in the state), “we aren't recommending that everyone who's had just one dose of the vaccine go out and get a second dose at this point. One dose of the vaccine offers substantial protection,” Herlihy said.
A single dose of the MMR vaccine confers 93% protection against measles, while a second one ups that number to 97%, according to the U.S. Centers for Disease Control and Prevention (CDC). People who have received the full series of the MMR shot don’t need another one after exposure to the virus, state health officials said.
Unvaccinated people exposed to the virus can get the MMR vaccine 72 hours after exposure (but before symptoms are present) to prevent an infection, officials said.
If you have spoken to a healthcare provider about your concerns and they have advised vaccination, the Joe Shoemaker School is hosting a clinic for routine childhood vaccinations on Wednesday, April 2, from 3 p.m. to 6 p.m. The school is located at 333 S. Havana St. in Denver.
The last time Colorado reported a measles case was in December 2023, which involved an international traveler who arrived to Colorado. Their vaccination status was never confirmed. Prior to that, Colorado had not seen a confirmed case of measles since 2019, during a global outbreak of the disease that also affected the U.S.
Measles was declared eliminated in the U.S. in 2000, meaning it is no longer constantly present in the country, though there is always a risk of small measles outbreaks when unvaccinated travelers come to the U.S. from countries that have not yet eliminated the disease.
That status is now at risk due to “an unusual and constant increase in confirmed cases of this disease” over the past several years, according to a recent report from the Pan American Health Organization (PAHO).
As of Friday, 483 confirmed measles cases were reported across 20 states in the U.S., with the overwhelming majority of those cases occurring among unvaccinated youth between the ages of 5 and 19 years old, according to the CDC.
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