Overall SSPE Risk in the General Population (Excluding Infants and Toddlers)
The risk of SSPE following measles infection in individuals beyond infancy and early childhood is approximately 4-11 per 100,000 measles cases, which represents a substantially lower risk compared to infection during the first years of life. 1
Population-Level Risk Estimates
The overall SSPE risk across all ages of measles infection is approximately 4 per 100,000 measles cases (or 1 in 25,000). 2
When excluding infants and toddlers from the calculation, the risk drops considerably since the highest-risk group (children infected before age 5, particularly those under 12 months) is removed from the denominator. 3, 4
Age-Stratified Risk Context
While you've asked to exclude infant/toddler data, understanding the contrast is essential for clinical context:
The statement that measles after age 5 carries negligible risk for SSPE is definitively false according to the Advisory Committee on Immunization Practices (ACIP). 1
SSPE can occur following measles infection at any age, with typical onset 6-8 years after the initial measles infection, generally presenting between ages 5-15 years. 1
The latency period from measles infection to SSPE diagnosis has a median of 9.5 years (range 2.5-34 years), meaning adult-onset SSPE following childhood or adolescent measles infection is documented. 4
Critical Clinical Pitfall
Clinicians should maintain awareness of SSPE in patients with compatible symptoms even in older patients with no specific documented history of measles infection, as many cases occur in individuals who had unrecognized or subclinical measles. 4
The male-to-female ratio is approximately 2.4:1, which persists across all age groups. 4
Prevention Remains Universal
Measles vaccination has essentially eliminated SSPE in highly vaccinated populations regardless of the age at which measles would have been contracted. 1, 5
The risk of SSPE following measles vaccination is no greater than 0.14 per 100,000 vaccinations, representing at least a 28-fold reduction compared to natural measles infection. 2
Adolescents and adults born after 1957 without documentation of two MMR doses or laboratory evidence of immunity should receive catch-up vaccination to prevent SSPE. 1