How Australia's commitment and activities for measles control achieved rubella elimination

Abstract

Background: The global measles and rubella strategic plan 2012–20 has a target for measles and rubella elimination in five WHO regions by the end of 2020. Only one region has eliminated rubella. The WHO Strategic Advisory Group of Experts on Immunization advised rubella control was lagging and recommended rubella vaccination be introduced into all country immunisation programmes as soon as possible. We describe the impact enhanced measles control activities, using measles-mumps-rubella (MMR) vaccines, had on rubella incidence in Australia and how these activities lead to the successful elimination of both viruses. Methods and materials: We reviewed rubella notifications from Australia's National Notifiable Disease Surveillance System (1991–2018) and stratified by age, sex and vaccination status. Three-year cumulative incidences were calculated by birth-cohort to assess the impact of two major measles immunisation activities in Australia; the 1998 Measles Control Campaign (MCC), targeted children 5–12 years; and the 2001 Young Adult MMR immunisation program (YA-MMR), targeted adults 18–30 years. MMR immunisation coverage estimates were extracted and compared with notification data. Aggregate national serological survey data (1999, 2002, 2007 and 2012) was assigned to birth-cohorts and the mean, median and ranges of age-group estimates were calculated. Results: The MCC attained 96% coverage, the three-year cumulative incidence of rubella declined by 90% compared with the three years preceding. This effect was also seen following the YA-MMR with a 73% decline in pre-and-post three-year periods, however vaccine coverage during this campaign was considerably lower. Serological surveys displayed a high and constant level of immune protection among females, but males were estimated to have 4–13% lower immunity. Rubella immunity significantly benefited by a direct 17% boost in serological immunity in those 6–11 years of age in the 1999 pre-and-post serological survey. Conclusion: The use of combined MMR vaccines to address measles immunity concerns in Australia demonstrated a symbiotic benefit in not only controlling and eliminating measles transmission but rubella as well. Although the coverage of the YA-MMR was considered to be “sub-optimal”, it effectively closed the rubella immunity gap in Australia, and demonstrates that utilising combination MR-containing vaccines in routine and mass vaccination programs is effective in eliminating the transmission of both viruses.