The epidemiology of rubella, 2007-18: an ecological analysis of surveillance data.

ABSTRACT

BACKGROUND: As of 2018, the rubella vaccine had been incorporated into the national immunisation schedule of 168 countries, representing 87% of the world's population. Countries have used different strategies to reduce the burden of congenital rubella syndrome (CRS), such as vaccinating only females. Given the different strategies, and that 26 countries still had not introduced the vaccine, we analysed global rubella surveillance data to understand rubella epidemiology and the effect of vaccination. METHODS: In this ecological analysis, we evaluated surveillance data on rubella cases that had been reported to WHO from 2007 to 2018, by age, vaccination history, and onset year. Cases were classified as either being vaccine eligible or ineligible on the basis of the country's vaccination strategy and the birth year of the person. We required all cases be confirmed by laboratory testing or that they were epidemiologically linked, and we excluded cases defined only by clinical symptoms. Incidence per million people was calculated by use of World Population Prospects data. FINDINGS: Between Jan 1, 2007, and Dec 31, 2018, from data reported to WHO as of Jan 3, 2020, there were 139 486 reported rubella cases, of which 15 613 (11%) were vaccine eligible. Annual incidence ranged from 13·9 cases per million in 2007 to 1·7 cases per million in 2018. In all years, absolute and proportional global incidence were higher among vaccine ineligible cohorts than eligible cohorts. In vaccine ineligible cohorts, 87 666 (74%) of 118 308 cases were in children younger than 15 years, compared with 8423 (54%) of 15 613 cases in vaccine eligible cohorts. Vaccine ineligible women of reproductive age (WRA) had a higher incidence than vaccine eligible WRA, except in 2011-12. INTERPRETATION: Vaccination has been successful in decreasing the burden of rubella, regardless of the strategy used. WRA remain at risk, but the risk is higher in those countries that have yet to introduce the vaccine. These countries should introduce the rubella-containing vaccine as soon as possible, to eliminate rubella, and to prevent the morbidity and mortality associated with CRS. FUNDING: None.