Subacute sclerosing panencephalitis

Abstract

Subacute sclerosing panencephalitis (SSPE) is a devastating neurodegenerative disorder due to a persistent mutated, wild-measles virus infection of the nervous system. While the acute infection is generally self-limiting, defective viral clearance can lead to the emergence of neurovirulent strains that undergo mutations within the host, evade immune surveillance, establishing chronic central nervous system (CNS) infection. It predominantly affects children and young adults although no age, including infants, is immune to SSPE. The characteristic neurological manifestations include progressive behavioral and cognitive decline, neuromotor impairment, myoclonus, vegetative state and death within 1-3 years of diagnosis, although prolonged stabilization and spontaneous resolution have been reported in a minority of patients. Despite global efforts towards measles elimination, SSPE remains a challenging problem in the low- and middle-income countries (LMICs) due to inadequate vaccine coverage. Limited health infrastructure, suboptimal surveillance, and limited availability of diagnostic tests hinders early diagnosis and management making SSPE a public health crisis. The measles outbreaks in high-income countries with developed vaccination programs are commonly due to international travel, immigration, and vaccine hesitancy, making it a global problem. The lack of effective antiviral therapy makes supportive and palliative care the primary management strategy once SSPE is confirmed. Recent research highlights potential therapeutic strategies, novel molecular approaches targeting mutant measles viruses, and enhanced public health measures to contain the outbreaks. However, these remain largely inaccessible in LMICs with measles endemicity and the high disease burden of SSPE. Urgent action is needed to bridge this gap by strengthening vaccination programs, implementing early diagnostic strategies, and enhancing access to emerging treatments. The current review discusses the various aspects of SSPE and the importance of preventive strategies for SSPE as relevant to LMIC. Without holistic efforts and a multi-pronged approach to eliminate measles and prevent SSPE, the disease shall remain a global threat.

Keywords: Measles; Neurodegeneration; SSPE; Subacute sclerosing panencephalitis.