Measles is back in the headlines. Outbreaks are popping up in states around the country.
If you still think measles is a “disease from the past,” you’re not imagining it. Measles was declared eliminated in the U.S. in 2000—meaning we stopped having continuous, year-round spread. But “eliminated” doesn’t mean “gone.” It means we only stay measles-free if we keep immunity high and respond fast to quarantine and isolate cases when cases appear.
Right now, the Carolinas are a case study in how modern outbreaks happen. South Carolina is experiencing a large outbreak (centered in Spartanburg County), and North Carolina has reported related cases and warned that at least one recent case has no identified exposure source, suggesting there may be additional infections that haven’t been detected yet.
The South Carolina Department of Public Health (DPH) is reporting 99 new cases of measles in the state since Tuesday, bringing the total number of cases in South Carolina related to the outbreak to 310. The outbreak remains centered around Spartanburg County, with most cases located in that region.
There are currently 200 people in quarantine and nine in isolation until January 29, 2026.
The number of those in quarantine does not reflect the number actually exposed. Consequently, these numbers will invariably increase. State epidemiologists are currently identifying public exposure sites and have concluded that hundreds more people exposed to measles are not aware they should be in quarantine if they are not immune to the virus. Many public exposure sites are elementary schools, day-care centers, airports, planes, waiting rooms, and hospitals.
Well-known measles transmission studies have shown that one measles case can result in up to 20 new infections among unvaccinated contacts.
Prevention recommendation measures for doctor’s offices, clinics, and hospitals include the use of masks and rapid isolation of suspect measles cases to protect staff.
A person with measles is contagious from four days before the rash appears, so measles may not be suspected. Someone can spread measles before they know they are infected. Additionally, the virus can remain airborne for up to about two hours after an infected person leaves a room. Therefore, it is very important for those with mild illness or those who are in quarantine to stay home to protect others from possible measles spread.
Vaccination with MMR continues to be the best way to prevent measles and stop the outbreak. Vaccines are available at primary care provider offices and pharmacies, as well as County Public Health Departments. You can use the South Carolina DPH Recommendations for Measles Vaccination chart to understand if you need to be vaccinated or not.
The current statistics in South Carolina are as follows:
Outbreak Data Points
Age breakdown of 310 cases:
Under 5: 69
5-17: 206
18+: 29
Minors under 18 (age undisclosed): 6
Vaccination status:
256 unvaccinated, 2 partially vaccinated with one of the recommended two-dose MMR sequence, 2 vaccinated, and 50 unknown but likely unvaccinated.
Let’s talk briefly about the science of measles outbreak disease—
Measles is communicated, person to person, by airborne viral droplets that will linger in the air for about 2 hours after an infected person leaves a room, whether they feel sick or don’t. Measles is among the most contagious of all human viral infections. Old data shows that about 9 out of 10 susceptible close contacts will become infected. “Susceptible” is defined as not having been properly vaccinated.
Outbreak risk rises sharply when vaccination coverage drops below the level public health experts determine is needed for community protection, about 95% coverage with a two-dose measles vaccine. The scenario that triggers an outbreak is first a reintroduction of the virus from travelers abroad who haven’t been vaccinated. Then comes exposure of a group of under-immunized people, exposure in high-contact settings like schools, churches, airports, waiting rooms, and a delay in detection because measles is communicable for four days prior to onset of symptoms and the earliest symptoms prior to rash onset appear like a common cold.
The only way to prevent the rapid spread of the disease is mass vaccination. The MMR vaccine is extremely effective. One dose is about 93% effective at preventing measles. A second dose is about 98% effective at preventing the disease. The first dose is given at 12-15 months; the second dose at 4-6 years, but can be given earlier as long as it’s been at least 1 month after the first dose. If an adult is uncertain about their vaccine status, it is best to vaccinate that individual; there is no harm in doing so.
The anti-vaccination movement is concerned that the MMR vaccine can cause autism. That concern is derived from a tiny 1998 study and a 2019 study associating the vaccine to the condition. Those studies have been debunked. Authorities in the U.S. have confirmed that autism is unequivocally not caused by the MMR vaccine. https://publichealth.jhu.edu/2025/vaccines-do-not-cause-autism; https://www.vaccinesafety.edu/do-vaccines-cause-autism/
But, personal choice is just one angle of the vaccination controversy. During a measles outbreak, the choice then becomes a community problem. Measles isn’t just an individual risk. It’s about who can’t be protected, including infants too young for routine vaccination, pregnant women who can’t receive live vaccines, and people who are immune-compromised. Outbreaks disproportionately harm these groups because measles spreads before the clinical condition becomes obvious. People are contagious before the rash appears, which makes “just stay at home if you’re sick” insufficient as a primary strategy. The only viable primary strategy to protect people is vaccination.
And the dangers?
Infants: pneumonia, severe dehydration, renal and respiratory failure, encephalitis, seizures, severe fever, multi-organ failure, septic shock, death. About 1 in every 5 unvaccinated children with measles in the U.S. will require hospitalization.
Pregnant Women: For the mother: pneumonia, respiratory failure, increased mortality. For the fetus: miscarriage, preterm birth, low birth weight, fetal death
Immunocompromised (people with cancer, organ transplants, autoimmune disease, those on chronic steroids, HIV , congenital immune disorders): death from disseminated system viremia leading to pneumonia and respiratory failure, encephalitis, multi-organ failure, and septic shock.
In summary, outbreak control involves case isolation, contact tracing, quarantine guidance for those who are ill and their contacts, targeting vaccination clinics, and healthcare alerts so clinics and emergency departments mask and isolate suspected cases immediately.
How do we avoid outbreaks in the future? Outbreaks happen when immunity dips and when people mix closely indoors. Routine vaccination rates must remain high everywhere, catch-up vaccination must be made easily accessible and free, and most importantly, the general public must follow the recommendations of the authoritative U.S. Departments of Public Health.
Americans must understand that vaccine safety and effectiveness are evaluated, licensed, and continuously monitored by multiple independent federal public health agencies, including the U.S. FDA, the CDC, an independent organization of vaccine experts, the ACIP (Advisory Committee on Immunization Practices).
The U.S. is arguably the most rigorous scientific and regulatory system in the world, and is multi-layered on purpose. The FDA decides if a vaccine is scientifically acceptable. The CDC watches what happens in the community receiving the vaccine. ACIP determines how the vaccine should be used. No single agency controls all three. This prevents political pressure, manufacturer influence, premature approvals, and undisclosed safety problems. This is why U.S. approved vaccines are automatically accepted by the WHO, most countries in Europe, Canada, Japan, and Australia.
For additional information about measles and measles vaccines or to retain me as an expert witness, please contact me.