In addition to its well-known effects on bone metabolism, vitamin D is an immunomodulating hormone. Serum vitamin D levels in males 18-25 years were measured at baseline, and HPV antibody titers were measured one month following the third quadrivalent HPV vaccine dose. Vitamin D levels were>30 ng/ml (normal) in 60 males and<30 ng/ml (low) in 113 males. Reverse cumulative distribution curves and scatter plots showed higher antibody titers with low vitamin D for all vaccine strains (P<0.05). In linear regression analyses, antibody titers for all HPV strains were significantly higher among those with lower vitamin D levels and among younger participants (P<0.05). These relationships add to the body of knowledge of the complex role of vitamin D in immunoregulation.

PURPOSE. To report a case of unilateral optic neuritis following Measles-Mumps-Rubella (MMR) vaccination.

METHODS. A 30-year-old female developed unilateral optic neuritis five days after a Measles-Mumps-Rubella (MMR) booster vaccination. The patient displayed unilateral involvement, with severe visual loss. However, visual acuity improved significantly after four days of intravenous steroid therapy with 500 mg/day of methylprednisolone.

CONCLUSIONS. Optic neuritis is one of the rare complications associated with the mumps, measles, and rubella vaccine. It may be a toxic reaction to the nonviral component of the vaccine, but the exact etiology is unknown. Postvaccination neuritis is generally bilateral and usually affects children. In adults, unilateral optic neuritis is usually correlated with multiple sclerosis (MS).