Incidence proportion for each 6-month period of zoster vaccination by calendar year from June 1, 2006, to December 31, 2009. The proportion is expressed as the proportion of unvaccinated individuals under observation and vaccinated in each 6-month period. It does not include individuals vaccinated in previous time periods.
Zhang et al. Arthritis Research & Therapy 2011 13:R174 doi:10.1186/ar3497