24 August,2026 11:54 PM IST | | Vinod Kumar Menon
Implementing universal measles vaccination could eliminate the threat of SSPE. Representation Pic/iStock
Subacute Sclerosing Panencephalitis (SSPE), a rare and devastating neurological complication of measles, can emerge years after the initial infection, progressively impairing a child's brain function, movement and independence.
Despite advances in understanding the disease, it remains without a definitive cure and continues to pose difficult medical and emotional challenges for affected families. In part eight of a nine-part series on SSPE, mid-day speaks to medical experts, who shed light on various facets of the condition.
Viswanathan LG, associate professor of neurology at NIMHANS, Bengaluru, and consultant neurologist and epileptologist, looks at SSPE from the scientific and clinical perspective, explaining the disease process, its biology, diagnosis and treatment options. NIMHANS receives many cerebrospinal fluid (CSF) samples from across the country for testing for SSPE. A positive result from NIMHANS provides strong laboratory confirmation of the disease in a patient who has signs and symptoms consistent with SSPE.
How many suspected SSPE cases does NIMHANS receive for diagnostic testing on average, and how many are confirmed as SSPE? Has this caseload changed in recent years?
I can only speak from personal experience rather than official NIMHANS statistics. In my own practice, I see roughly 15 to 20 suspected SSPE cases each year, and I've personally evaluated close to 100 cases since 2022. Anecdotally, the numbers haven't dropped as much as one would hope, given measles vaccination coverage, though this impression is based on my own caseload rather than institutional data.
What are the latest advances in the diagnosis of SSPE, and are newer techniques helping doctors detect the disease earlier and more accurately?
Diagnosis still rests mainly on a combination of clinical features (progressive cognitive decline, myoclonus), characteristic EEG (electroencephalography) patterns, and elevated anti-measles antibody levels in cerebrospinal fluid. It is not difficult for an experienced neurologist to diagnose and can be suspected with a high degree of confidence based on clinical and EEG findings.
Does current research reveal why the measles virus can remain hidden in the brain for years and later cause SSPE in some children?
The broad understanding is that the measles virus can persist in the brain in a mutated, "defective" form that evades the immune system, replicating slowly without triggering the usual defences. Our own work at NIMHANS looked specifically at the IL-12/interferon-gamma axis, a pathway central to the body's antiviral defence, and found it may play a role in how the disease develops. Certain traits may make a person susceptible to SSPE in addition to viral and host factors. This complex interplay may be the reason why only a few develop this devastating complication after measles infection. Over the years, this low-grade persistent infection eventually causes progressive brain damage.
How close are we to finding a definitive cure for SSPE? What are the most promising areas of R&D?
There is no definitive cure yet. Current approaches like antiviral drugs and immune-modulating therapies (interferon, isoprinosine, and others) can sometimes slow progression in a subset of patients, but don't reverse the disease. There are rare instances in which the disease may temporarily remit, but it eventually relapses.
From your experience examining SSPE cases, what is the biggest scientific question that researchers need to answer to develop an effective treatment or cure?
In my view, the central unanswered question is why the virus persists and reactivates in some children but not others after a measles infection. Understanding that mechanism would open the door to real prevention and treatment strategies, rather than the largely supportive care we can offer today.
Why do you think this rare, devastating, and usually fatal neurological disease has not received specific recognition under India's rare-disease framework?
This likely reflects a mix of factors: SSPE isn't as widely recognised publicly as some of the other rare diseases, there's limited advocacy specifically around it, and it's sometimes viewed as a "consequence" of measles rather than a distinct disease entity needing its own framework. This gap in recognition can affect access to support and resources for affected families.
If you could make one immediate recommendation to the Union Health Ministry for families affected by SSPE, what would it be?
It would be to establish structured support, including financial assistance and access to centres with expertise for a definitive diagnosis of SSPE. Also, SSPE should be made a reportable illness and an effort to maintain nationwide statistics should be made.
Dr Anaita Udwadia Hegde, consultant, paediatric neurology at Mahalaxmi's SRCC Children's Hospital, managed by Narayana Healthcare, brings her unique perspective on disease progression, treatment, neurological and supportive care, and the realities faced by children and their families after diagnosis.
When you first began treating children with SSPE, how was the disease understood, and what do you remember most vividly about those early patients and their families?
I have been practising paediatric neurology for 26 years, and unfortunately, the condition of children with SSPE, from the early and late 1990s to today, remains relatively the same. SSPE still does not have a treatment or cure supported by strong scientific evidence. Over the years, numerous different treatment options have been tried for these children.
Measles vaccination policies and compliance have been strengthened and enforced worldwide, with the hope that the incidence of SSPE would come down.
It was certainly far more common when I was a resident and young medical student than it is today. But we still see SSPE, on average, I still see one child every one to two months, and that should not be the case.
Medicine has changed enormously over the decades. How has this technological evolution changed the way you identify and document SSPE?
The basic parameters we use have remained the same. We do a CSF test to confirm measles infection in the brain, an EEG to look for the characteristic discharges, and an MRI (magnetic resonance imaging) to assess the extent of involvement, including the white matter, grey matter and overall brain involvement. We use EEG to monitor children over time, but beyond these investigations, there is no specific monitoring tool other than the clinical picture and progression of the child.
Have advances in imaging, EEG, laboratory testing and neurological care actually translated into earlier diagnosis or better outcomes for children with SSPE, or has the prognosis remained largely unchanged?
Yes, with these advances, we may be able to pick up SSPE a little earlier. Patients typically go through multiple stages, starting with cognitive decline, followed by falls, motor regression, feeding difficulties, speech impairment and loss of other developmental abilities.
However, earlier diagnosis does not necessarily translate into better outcomes because we still do not have a foolproof treatment. Over the years, numerous treatments have been tried, both here and abroad, but none have proved consistently beneficial.
The concern with SSPE is that, while most patients continue to progressively deteriorate, the natural history of the disease shows that some may stabilise and remain static for months or even years. A few may even show exceptionally mild improvement.
Looking back at the children you treated in the early years and comparing them with patients you see today, what has genuinely improved in the management of SSPE, and where do you feel medicine has made disappointingly little progress?
Since SSPE is a slow viral disease, it has an incubation period of around six to eight years on average before a child develops symptoms. By the time the child manifests with the clinical spectrum and the EEG and MRI findings, we are already pretty late in the disease process when we start treatment. Ideally, we would want to identify and intervene much earlier, but it is very difficult because there are no signs and symptoms in the initial years.
While diagnosis and management have improved, we have made very little progress in changing the long-term outcome once the disease develops. The only way to eliminate SSPE is to eradicate measles by ensuring that every child worldwide is vaccinated properly and protected from measles and its complications.
For families, the most difficult reality is watching a child progressively lose abilities such as movement, communication, and independence. How has your approach to supporting and counselling these families evolved over the years?
Breaking the news of the devastating diagnosis, supporting families through the different stages of the disease and discussing its prognosis, trying treatment options at varying stages, and then counselling the family with regard to long-term rehabilitation, all of this is part of supporting these families.
Over the years, I have increasingly come to believe that the most important support we can offer families is prevention. The best outcome for a child with SSPE is to prevent the disease from occurring in the first place. This means ensuring timely measles vaccination and preventing complications of measles such as SSPE. Vaccination is meant to prevent measles infection and, consequently, its complications. Ultimately, preventing SSPE is far better than having to counsel families through its devastating course.
After decades of treating SSPE, what do you believe remains the biggest unresolved challenge in terms of changing its outcome for children?
One aspect I would like to touch upon is the plight of families. I have seen the immense pain of parents watching their child gradually lose cognitive, motor, social and basic functional abilities. What makes SSPE particularly devastating is its slow progression. A child may remain in a state of severe deterioration for years before eventually passing away. For parents, living through this prolonged decline is heartbreaking.
Parents will try everything and anything under the sun. We have seen families move from allopathy to alternative therapies, different medications and combinations of treatments, often out of desperation to help their child. Sometimes, these approaches may show partial or temporary improvement, but unfortunately, the long-term picture is usually not positive.
So, the biggest unresolved challenge is not just understanding the disease, but finding treatments that can truly alter its long-term course and give these children and their families a better outcome.
If you could tell researchers, clinicians, and policymakers to focus on one change today that could make the greatest difference to children with SSPE and their families, what would you want that change to be?
What I would like researchers, clinicians and policymakers to focus on is the implementation of universal measles vaccination, along with finding evidence-based treatments that are effective in the long term and accessible to families early in the course of SSPE. Parents should not have to try everything out of desperation; they need clear guidance, better treatment options and hope based on scientific evidence.
