No abstract available
MeSH terms
-
Biomedical Research / methods
-
Central Nervous System Diseases / epidemiology*
-
Child
-
Demyelinating Diseases / epidemiology*
-
Epidemiologic Research Design
-
Hepatitis B Vaccines / adverse effects*
-
Humans
-
Multiple Sclerosis / epidemiology*
-
Odds Ratio
-
Risk Factors
-
Time Factors