ing disorders. There are no data bearing on the biologic plausibility that measles vaccine specifically can cause optic neuritis.

There are several reports of optic neuritis following measles vaccination. A 6-year-old boy developed bilateral optic neuritis 18 days after an injection of MMR. He was treated with corticosteroids and experienced a complete resolution after several weeks (Kazarian and Gager, 1978). Marshall et al. (1985) described a 16-month-old girl who experienced an acute loss of vision 16 days after an injection of MMR. Two days earlier she felt warm to the touch and developed a cough, conjunctivitis, and a generalized maculopapular rash. Examination revealed diffuse chorioretinitis and papilledema, which ultimately evolved into a "salt and pepper" pattern. Seven months later she improved, but she had macular scarring. Riikonen (1989) described 18 children with optic neuritis following infection, vaccination, or both. Of those 18, 10 went on to develop multiple sclerosis. Six of these children had been vaccinated between 3 days and 1 month before the onset of optic neuritis, but none had received measles vaccine during that time period. All 18 of the children were reported to have received measles vaccine (unspecified) between 12 and 18 months of age; the age of onset of optic neuritis ranged from 5 years 2 months to 14 years 10 months.

None.

None.

There is demonstrated biologic plausibility of a causal relation between optic neuritis and measles vaccine, in that measles virus is associated with demyelinating disorders. The number of reported cases is too small and the data contained within the reports are too equivocal to support a positive association between measles vaccine and optic neuritis. As discussed in Chapter 3, optic neuritis can result from many causes and is frequently associated with multiple sclerosis.