Importance of Catch-up Vaccination: Experience From a Varicella Outbreak, Maine, 2002–2003

Abstract
Objective. During December 2002 to January 2003, a varicella outbreak occurred in an elementary school in Maine. Just 1 month before detecting the outbreak, Maine implemented varicella vaccine requirements for child care but did not require vaccination for school entry. We investigated this outbreak to examine reasons for its occurrence, including vaccine failure.