Risk of SSPE When Accounting for Measles Underreporting

Quantifying the True SSPE Risk

The true risk of SSPE following measles infection is approximately 4-11 per 100,000 measles cases, but this substantially underestimates the actual risk because measles cases are dramatically underreported, with only about 11% of actual infections being officially reported, according to the Centers for Disease Control and Prevention (CDC) 1
Before measles vaccine licensure in 1963, approximately 400,000 measles cases were reported annually in the United States, but the actual number of cases approached 3.5 million per year, meaning reported cases represented only about 11% of true infections, as stated by the CDC 1

The Advisory Committee on Immunization Practices (ACIP) definitively states that MMR vaccine does not increase the risk for SSPE, even in persons who previously had measles or received prior measles vaccine 2, 3
Widespread measles vaccination has essentially eliminated SSPE from the United States, according to the CDC 1
Measles vaccination is the only effective prevention strategy for SSPE, as recommended by the ACIP 2, 3

Immunocompromised individuals can experience severe and prolonged measles infection, as noted by the American Academy of Pediatrics (AAP) 4