A row of clear glass vaccine vials with a syringe resting against them on a grey background

Are You Still Protected From Measles? The 1963 to 1967 Vaccine Gap and What Adults Should Do

On October 8, 2026October 28, 2026 By Dr. Scott RennieIn Infectious DiseaseLeave a comment

Pennsylvania crossed a thousand measles cases this week. The state is at 1,078 across 41 counties, with 207 hospitalizations and five measles-associated deaths, and Lancaster County alone accounts for 401 of them. Nationally we are at roughly 3,880 cases. That is the highest annual total since 1991.

New York’s governor declared a disaster emergency on Monday so that paramedics, pharmacists and midwives can give vaccines. Florida’s health department held a hearing in Orlando on October 8 on dropping hepatitis B, chickenpox, Hib and pneumococcal from its school and daycare requirements. Measles is not among them. The MMR requirement is written into state statute, so only the legislature can touch it. Comment on the other four closed on October 19 and the rule has not been adopted.

Almost all of the coverage is about children, because that is where the cases are.

I have had one of these myself, by video. An unvaccinated child, high fever, body aches, and a rash whose appearance made me think measles before I thought of anything else. Looking like measles is not the same as being measles. Confirmation takes a swab for PCR and a blood sample for measles IgM, and neither of those travels down a camera, so that visit ended where it had to end, in a referral for testing in person.

That is the honest limit of the work I do. I could recognize it. I could not prove it.

The question I get by video is a different one, and it comes from adults. Some version of: am I still covered?

It is a better question than it sounds, because for a specific group of people the honest answer is no.

The 1963 to 1967 problem

There were two measles vaccines licensed in 1963. One was a live attenuated vaccine, which is the ancestor of the MMR we give now. The other was an inactivated vaccine, a killed-virus product that was pulled from the market in 1967 because it did not work well enough.

It did something worse than not working. Some people who got the killed vaccine and later met the real virus developed atypical measles syndrome, an unusually severe illness with high fever, an odd rash that starts on the extremities, and pneumonia.

So the guidance is specific. Anyone vaccinated before 1968 with killed measles vaccine, or with a vaccine of unknown type, should be revaccinated with at least one dose of live attenuated measles vaccine. If you are in a high-risk group, that becomes two doses.

The number of people affected is small. The CDC puts it at under five percent of adults. Immunize.org estimates fewer than a million Americans.

Here is the practical problem with a small number. Almost nobody born in that window knows which shot they got. The record, if it exists at all, is a line in a pediatrician’s file from sixty years ago, and that pediatrician has been retired for thirty of them. “Measles vaccine, 1965” does not tell you which product it was.

Which is why the rule says unknown type counts the same as known killed. If you cannot establish it was the live vaccine, you are treated as though it was not.

If you were born before 1957

You are presumed immune and you do not need anything.

That cutoff is not a guess about vaccines. It is a statement about how common measles was. Before the vaccine existed, essentially everyone caught it in childhood, so the assumption is that you already did, whether or not you remember it.

One exception, and it is the one that applies to me and to anyone else reading this who works in health care. For healthcare personnel, facilities should consider vaccinating staff born before 1957 who have no laboratory evidence of immunity and no laboratory confirmation of past disease. The presumption is good enough for the general public. It is not good enough for someone standing in a room with a febrile child.

Should you get a titer drawn?

Usually not, and this is where I disagree with how the question is often handled.

The CDC does not recommend routinely screening adults for measles immunity outside an outbreak area, and it does not recommend testing after vaccination to confirm it took. If you have documentation of two MMR doses, you are done. No blood draw adds anything.

A titer is useful in one specific situation, which is when you genuinely do not know your history and the result would change what happens next. Positive measles IgG means immune. Negative or equivocal means treat as non-immune, unless you meet one of the other criteria such as birth before 1957.

But consider the arithmetic before you order it. An MMR dose costs less than the antibody test in most places, takes one visit instead of two, and carries no penalty if you turn out to have been immune all along. An extra dose in someone who is already protected does nothing at all. It does not boost, it does not harm, it simply has no target.

So for most adults who are uncertain, getting the shot is faster and cheaper than proving you do not need it.

The exception worth naming is pregnancy. MMR is a live vaccine and is not given during pregnancy, so a woman who is pregnant and uncertain about her status gets the titer instead, and the vaccine afterward if she needs it.

About the death count, since you will see it argued about

Pennsylvania reports five measles-associated deaths this year. The CDC’s national count is two, and the CDC’s database does not say which states those two are in.

That gap is real and it is worth understanding, because it is being read as evidence of a cover-up in one direction and of inflated numbers in the other.

The mechanism is duller than either. The CDC moved to counting measles deaths from National Center for Health Statistics mortality data, which is built from death certificates and lists an underlying cause, rather than from state health department reports. NCHS data is designed to measure long-term trends across a population. It was not built to adjudicate individual infectious disease cases in the middle of an outbreak, and it runs on a slower clock, which is the substance of what the outside experts objecting to the change have said.

Pennsylvania uses a different definition: a laboratory-confirmed measles infection and death within thirty days of symptom onset, absent an obvious unrelated cause such as a car crash.

Both definitions are defensible. They will produce different numbers during a fast-moving outbreak, and the federal one will lag.

There is also a political layer, which I will describe rather than referee. The CDC initially included Pennsylvania’s first two deaths and then removed them pending review, after the Health Secretary publicly questioned whether measles had caused them. That detail was first reported by a Substack citing an anonymous CDC employee, so I hold it more loosely than the rest of this. The count later returned to two after NCHS verified one death. Pennsylvania has since conditioned its request for federal Epi-Aid assistance on the CDC publicly recognizing the state’s full count.

What I would say clinically is narrow. Of Pennsylvania’s five, two were unvaccinated adults, aged 18 and 40, and two were infants too young to be vaccinated. That pattern is what measles mortality has always looked like. It kills the unprotected and the too-young-to-protect, and it does so through pneumonia and encephalitis rather than through the rash anyone remembers.

As the infectious disease physician Amesh Adalja put it, to the public a gap like this looks like either incompetence or concealment. Neither is true here, and the fact that neither is true is not doing much to help.

What I would actually do

If you have records showing two MMR doses, nothing. You are protected and the protection does not fade.

If you were born before 1957 and do not work in health care, nothing.

If you were vaccinated between 1963 and 1967, or you have no idea what you got and you were born after 1957, get one dose of MMR. Do not spend three weeks trying to find a sixty-year-old paper record first.

If you are pregnant and uncertain, ask for the titer, and plan the vaccine for after delivery.

And if you have an infant under twelve months in a household traveling to an outbreak area, that is a real conversation with your pediatrician about an early dose, which is a thing that exists and is not widely known.

The Bottom Line

Measles is at a thirty-five year high, and the people getting sick are overwhelmingly children who were never vaccinated. That is a different problem from the one most adults are asking me about.

For adults, the short version is that the vaccine works, it does not wear off, and the only real gap is a four-year window in the sixties when a product that did not work well was in use. If you fall in that window or you simply cannot establish what you got, a single MMR dose closes it, and it is cheaper and faster than proving you were fine all along.

Sources

Pennsylvania Department of Health Provides Statewide Update on Measles Outbreak as Cases Reach 1,078 in 41 Counties. Pennsylvania Department of Health, October 7, 2026. https://www.pa.gov/agencies/health/newsroom/pa-department-of-health-provides-statewide-update-on-measles-out9
Measles cases surpass 1,000 in Pennsylvania amid the state’s largest outbreak in decades. ABC News, October 2026. https://abcnews.com/Health/measles-cases-surpass-1000-pennsylvania-outbreak-continues-spread/story?id=137002024
Pennsylvania confirms fifth measles-associated death as US outbreak grows. Al Jazeera, September 30, 2026. https://www.aljazeera.com/news/2026/9/30/pennsylvania-confirms-fifth-measles-associated-death-as-us-outbreak-grows
New York governor declares measles emergency. CT Mirror, October 7, 2026. https://ctmirror.org/2026/10/07/new-york-measles-emergency-hochul
Vaccine change may bring largest measles outbreak ever. WGCU, October 7, 2026. https://wgcu.org/health/2026-10-07/vaccine-change-may-bring-largest-measles-outbreak-ever
Measles Cases and Outbreaks. Centers for Disease Control and Prevention. https://www.cdc.gov/measles/data-research/index.html
Measles Vaccine Recommendations. Centers for Disease Control and Prevention. https://www.cdc.gov/measles/hcp/vaccine-considerations/index.html
Questions About Measles. Centers for Disease Control and Prevention. https://www.cdc.gov/measles/about/questions.html
Ask the Experts: MMR (Measles, Mumps, and Rubella). Immunize.org. https://www.immunize.org/ask-experts/topic/mmr/
Measles Prevention: Recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR. https://www.cdc.gov/mmwr/preview/mmwrhtml/00041753.htm
CDC’s new tracking method for measles deaths puzzles experts. CIDRAP, University of Minnesota. https://www.cidrap.umn.edu/measles/cdc-s-new-tracking-method-measles-deaths-puzzles-experts
Measles is spreading across the US and officials can’t agree on the death toll. The Conversation, 2026. https://theconversation.com/measles-is-spreading-across-the-us-and-officials-cant-agree-on-the-death-toll-293234
Changes to CDC Vaccine Recommendations in 2025 and 2026. Congressional Research Service, IN12684. https://www.congress.gov/crs-product/IN12684

Glass of water and digital thermometer on a bedside table

Measles Is Back: What Urgent Care and Telemedicine Clinicians Need to Watch For

On February 27, 2026September 11, 2026 By Dr. Scott RennieIn Infectious DiseaseLeave a comment

Measles is back in our daily practice in a way many of us have never seen in our careers. In just the first weeks of 2026, the United States has already recorded more than 900 confirmed measles cases, with most linked to active outbreaks rather than isolated travel related infections. Those numbers are not abstract. They reflect real patients who often first appear with what looks like an ordinary viral upper respiratory infection.

In Virginia, where some of my colleagues practice, the health department has already confirmed 10 measles cases this year, the majority in young children in the Northern region. Public exposure sites in that region now include grocery stores, urgent care centers, emergency departments, churches, and big box retailers, with symptom watch dates stretching into early March. That list reads like a map of daily life, which is exactly the point. Measles is circulating in the same spaces our patients and our own families move through every day.

Clinically, we know this pattern. Early measles often looks like influenza or another common respiratory virus, with fever, cough, coryza, and conjunctivitis. The rash, when it appears, typically starts on the face or hairline and then spreads down the body over several days. The catch is timing. Patients are contagious for about four days before the rash and about four days after it appears, which means they have already spent several days at work, school, religious services, or stores while shedding virus. On a virtual visit, we are often meeting them right in the middle of that window.

On a 24/7 virtual care platform, measles usually does not present with a red flag label in the chief complaint. Instead, it shows up as “fever and cough,” “pink eye,” or “rash on face” typed into a symptom field at 10 p.m. A typical encounter might start with a parent worried about a toddler who has had three days of high fever, a worsening dry cough, a streaming nose, and eyes that are red and watery. The parent may have tried acetaminophen and fluids at home and is now concerned because the child just looks wiped out. At that point there may be no rash, or the parent might mention a few faint spots on the forehead that they are not sure about.

The current outbreaks highlight just how contagious measles is. The virus lives in the nose and throat and is released into the air when an infected person breathes, coughs, or sneezes. It can remain viable in the air or on surfaces for up to two hours after the person leaves. This is why unannounced walk ins to clinics or emergency departments are so risky and why strict infection control and coordination with public health are not optional. One infectious patient who sits in a crowded waiting room can trigger a long chain of secondary cases.

From an epidemiologic standpoint, the current U.S. numbers are sobering. As of mid to late February 2026, national case counts have passed 900 and are now over 1,100, with infections documented in more than two dozen states. A large share of these cases are tied to ongoing outbreaks that began in 2025 and spilled into this year. The vast majority of patients are unvaccinated or have unknown vaccination status, often children and adolescents. Hospitalization rates vary by age, but recent CDC data show that even in 2024, several percent of cases required inpatient care, with higher risk among young children and adults. Measles can lead to pneumonia, encephalitis, and death, even in high resource settings.

On the Virginia Department of Health dashboard, six of the ten cases reported in 2026 have occurred in children under five years old, a group that cannot always be fully immunized yet and that we worry about the most. That number is the one I keep coming back to. Exposure notifications list locations like a grocery store in Lorton, multiple retail sites and restaurants in Manassas, a church, and an office building in Alexandria, each with specific time windows and follow up symptom watch dates 21 days out. It is easy to imagine the scenarios. A preschooler with early measles sitting in a shopping cart. A young adult with mild symptoms walking into an urgent care center after work. These are ordinary moments that turn into public health events.

For virtual care clinicians, the practical question is what to do when that next “simple viral illness” consult pops up in the queue. First, we cannot afford to ignore vaccination status. Every patient with upper respiratory symptoms, especially in outbreak regions, should be asked directly about MMR doses and prior measles infection. This includes adults who vaguely recall “getting shots as a kid” but are not sure which ones. Second, we need to look closely at risk factors: unvaccinated or incompletely vaccinated patients, infants who are too young for full immunization, immunocompromised individuals, pregnant patients, and anyone with recent travel to areas with known outbreaks or exposure to crowded settings.

When clinical suspicion is high, escalation needs to happen quickly and in a structured way. Patients should be referred for immediate in person evaluation and diagnostic testing in a setting that is prepared to implement airborne precautions. Instead of showing up unannounced at a clinic or emergency department, patients should call ahead, so infection prevention teams can arrange safe arrival and isolation. Coordination with local health departments is key. I haven’t hit real friction getting a family to follow that plan, since I haven’t had a suspected measles case reach that point yet. What I do run into, often, is patients, mostly kids, who are unvaccinated because a parent made that choice on purpose and says so plainly when I ask. On the Virginia site, there is even a specific survey link for people who may have been exposed, which triggers public health follow up. Similar mechanisms exist in other states and are often underused.

Virtual clinicians also have a clear boundary here. On the Teladoc platform, for example, management of suspected or confirmed measles is explicitly prohibited, and all such cases must be referred to in-person care. That restriction exists because measles care and infection control require physical assessment, access to testing, immunoglobulin and vaccine for post-exposure prophylaxis, and the ability to initiate supportive treatment for complications, none of which can be delivered over video.

Vaccination remains the core prevention strategy. Two doses of MMR vaccine provide about 97 percent protection against measles. Breakthrough infections can occur, but they are uncommon, and most cases in the current outbreaks are in people who are unvaccinated or not fully vaccinated. The Virginia data show that over 90 percent of the state’s population, and roughly 95 percent of kindergarteners, are vaccinated against measles, yet small pockets of under vaccination have still allowed the virus to spread. In every virtual encounter, we have a chance to answer questions, correct misinformation, and nudge patients toward getting up to date on their shots.

I haven’t personally managed a confirmed measles case over telemedicine. But here’s the kind of scenario clinicians in virtual care should be watching for, a hypothetical built from the pattern these outbreaks produce, not a real patient of mine: A college student logs on late at night with a fever, sore throat, and mild cough after returning from a service trip where they worked in crowded community settings. They mention that their university recently sent out an email about a measles exposure but they “think” they had all their vaccines as a child. As the clinician, you dig a little deeper, learn there is no documentation of a second MMR dose, and find that the student has started to notice a faint rash near the hairline. In that moment, treating this as a routine viral upper respiratory infection would be a miss. Instead, you walk the student through the concern for measles, arrange urgent in person evaluation, instruct them to call ahead before arrival, and notify your internal public health liaison to coordinate with the local health department. That single decision can prevent dozens of secondary cases in a dormitory and on campus.

The current surge of measles cases is a reminder that this disease remains an ongoing threat, one that follows gaps in vaccination and public health infrastructure. For those of us working in virtual care, our role is to keep it on the differential, ask the extra questions, recognize the pattern a day or two earlier, and move swiftly when suspicion is high. The work can feel routine until it is not. Two years ago I wasn’t asking about immunization status at every visit. I do now, at any health-related visit, and especially with kids. I’ve also changed how I handle a rash over video, because video alone is generally not as good quality as a high-resolution photo. Getting a usable photo takes some coaching. The patient needs to stand back far enough, get the angle right, and hold the phone steady so it isn’t blurry. I like a distance shot to see the whole pattern and a macro shot up close if the patient can manage it.

Centers for Disease Control and Prevention. Measles Cases and Outbreaks. Updated February 26, 2026. Available at: https://www.cdc.gov/measles/data-research/index.html. Accessed February 27, 2026.

Centers for Disease Control and Prevention. Measles Vaccination. Updated December 29, 2025. Available at: https://www.cdc.gov/measles/vaccines/index.html. Accessed February 27, 2026.

Centers for Disease Control and Prevention. Measles, Mumps, and Rubella (MMR) Vaccination: Information for Healthcare Professionals. Updated January 25, 2026. Available at: https://www.cdc.gov/vaccines/hcp/by-disease/mmr.html. Accessed February 27, 2026.

Virginia Department of Health. Measles. 2026. Available at: https://www.vdh.virginia.gov/measles/. Accessed February 27, 2026.

Virginia Department of Health, Office of Emergency Preparedness. VDH OEP Weekly Situation Update. Published February 19, 2026. Available at: https://www.vdh.virginia.gov/emergency-preparedness/2026/02/20/vdh-oep-weekly-situation-update-137/. Accessed February 27, 2026.

Virginia Department of Health. Virginia Health Officials Investigating Two Confirmed Measles Cases in Northern Virginia. News release, February 18, 2026. Available at: https://www.vdh.virginia.gov/news/public-relations-contacts/2026-regional-news-releases/virginia-health-officials-investigating-two-confirmed-measles-cases-in-northern-virginia/. Accessed February 27, 2026.

Robinson A. VDH: Measles outbreak not likely in Northern Virginia despite uptick in cases. ALXnow. Published February 22, 2026. Available at: https://www.alxnow.com/2026/02/23/vdh-measles-outbreak-not-likely-in-n-va-despite-uptick-in-cases/. Accessed February 27, 2026.

WSBT / Sinclair Broadcast Group. Measles cases surpass 1,100 so far in 2026 as outbreaks continue to spread. Published February 26, 2026. Available at: https://wsbt.com/news/nation-world/us-measles-cases-surpass-1100-so-far-in-2026-health-experts-warn-centers-for-disease-control-and-prevention. Accessed February 27, 2026.

Dr. Scott Rennie

Tag: MMR vaccine