Protecting the Next Generation: Why the MMR Vaccine Remains Our Best Defense
In the year 2000, the United States reached measles elimination status. This was quite a milestone. While there have been limited cases since that time, mostly due to international travel, spread within communities in the US was limited due to continued high vaccination status conferring herd immunity. However, as vaccine rates have dropped, there has been an increased in transmission within the United States, especially in communities with low vaccination rates. 2025 has seen the most cases in the last 30 years, surpassing 2000 cases as of December 31, 2025. As a pediatrician, I have spent much of the last few years—and especially these first few days of 2026—considering the implications for a rise in a highly infectious disease and what it means for our community.
One of The Most Contagious Diseases in the World
If an infected person is in a room, the virus can linger in the air for up to two hours after they leave. 9 out of 10 unimmunized people that enter that room, even without direct contact, will contract the virus. Part of the difficulty is that measles is contagious 4 days before the rash appears, before they have any signs of illness.
Measles isn’t just a “minor rash.” Once the symptoms become apparent, people with measles are profoundly ill. It typically starts with what looks like a severe cold—high fevers often reaching 104°F, a hacking cough, and inflamed, watery eyes that are sensitive to light.
The signature red, blotchy rash usually begins at the hairline and sweeps down the body like a wave. The illness typically lasts about a week if it is uncomplicated, but when complications do occur, it can include ear infections, severe GI symptoms, dehydration, pneumonia, which remains the leading cause of measles-related death, and encephalitis (brain swelling) which can also cause death or permanent neurological damage.
The Hidden Danger: “Immune Amnesia” and SSPE
One of the most harrowing aspects of measles is a phenomenon called “immune amnesia.” The measles virus is unique; it doesn’t just make a child sick today—it actually “wipes” their immune system’s memory. It destroys the antibodies they’ve built up against other illnesses like the flu or strep throat. This leaves the child vulnerable to other dangerous infections for months or even years after they recover from the measles itself.
Years after a measles infection, a rare, but fatal brain disease called subacute sclerosing panencephalitis (SSPE) can occur. It affects 1 in 10,000 people that contract measles, but if a child contracts it before their first birthday, the risk soars to 1 in 600. There is no cure.
Protection Through Prevention
In 2025, we saw a heartbreaking rise in cases across the country because our herd immunity dropped below the critical 95% threshold. This leaves the most vulnerable members of our community—infants too young to be vaccinated and children with suppressed immune systems—at grave risk.
The MMR (Measles, Mumps, and Rubella) vaccine is one of the most successful tools in medical history. The MMR vaccine has been in use since 1971, for over 50 years. Two doses are 97% effective at providing lifelong protection. If you are unsure of your child’s status, I encourage you to visit the American Academy of Pediatrics (AAP) parent site for evidence-based information. The Children’s Hospital of Philadelphia also has an excellent Vaccine Education Center website that provides excellent information.
Your pediatrician has a wealth of information about infectious diseases and prevention. I encourage you to seek advice of trusted health professionals with any questions you may have on how to protect your children against infectious diseases.
