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Correspondence
www.thelancet.com Vol 380 July 21, 2012; best viewed at www.thelancet.com
The GAVI Alliance has announced support for eligible countries to introduce measles-rubella vaccine in their routine infant programmes and to start measles-rubella vaccine campaigns in children aged 9 months to 14 years. 30 countries are expected to have done so by 2015.1
Control programmes for congenital rubella syndrome need to consider features that affect rubella transmission rates and thus the risk of infection during pregnancy.2 These include: variation in vaccination coverage within and between countries; birth rate (at high birth rates, coverage well above 80% might be needed to avoid increasing the prevalence of susceptible adult women); and population isolation (local rubella extinction increases the mean age of infection in epidemics after rubella’s eventual reintroduction).2 The introduction of new and underused vaccines is affected by a country’s interest and its ability to obtain GAVI support (determined by gross national income and estimated coverage of three doses of diphtheria, tetanus, and pertussis vaccine) or other finance. Although the new global measles and rubella strategic plan3 encourages all countries to aim for control of congenital rubella syndrome and measles elimination, countries that receive GAVI funding might be quicker to introduce rubella containing vaccine than those that do not receive such funding. Since GAVIeligible and non-eligible countries and those with high and low coverage border each other, the usual process for introduction of new and underused vaccines will increase heterogeneities in rubella transmission across national boundaries. Countries that implement campaigns will strikingly reduce transmission in those younger than 15 years in the short term. This outcome will potentially increase the average age at infection in border areas of a neighbouring, nonvaccinating country, while currently susceptible adults will risk infection through travel to non-vaccinating countries or via imported cases. Vaccination of adolescent or adult women, part of successful congenital rubella syndrome control and elimination strategies,4 is not included in current plans. The unprotected population in the vaccinating country will build up again owing to pockets of low immunisation coverage in infants unless active measures are taken to reduce historical inequities. Large measles outbreaks with a significant increase in the average age of infection have occurred in many countries that had apparently achieved measles control, owing in part to suboptimum implementation of programme strategies.5 Such an occurrence for rubella, made more likely if the introduction of rubella containing vaccine occurs piecemeal, could decrease public confidence in immunisation even if the cumulative burden of congenital rubella syndrome is reduced.
Support for rubella-containing vaccine should not be “business as usual” at a time when multiple new vaccines are being introduced. Strong, sustained regional programmes that span countries of all income groups and specifically address rubella epidemiology are required to achieve the desired results.
This work was funded by the Bill & Melinda Gates Foundation. We declare that we have no conflicts of interest.
*F T Cutts, C J E Metcalf, J Lessler, B T Grenfell
felicity.cutts@wanadoo.fr
201 Boulevard Louis Bernard, 83250 La Londe les Maures, France (FTC); Department of Zoology, Oxford University, Oxford, UK (CJEM); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA (JL); and Department of Ecology and Evolutionary Biology, Eno Hall, Princeton University, Princeton, NJ, USA (BTG)
1 Burki T. GAVI Alliance to roll out rubella vaccine. Lancet Infect Dis 2012; 12: 15–16.
2 Metcalf CJE, Lessler J, Klepac P, Cutts F, Grenfell BT. Minimum levels of coverage needed for rubella vaccination: impact of local demography, seasonality and population heterogeneity. Epidemiol Infect 2012; 16: 1–12.
3 WHO. Global measles and rubella strategic plan: 2012–2020. http://www.who.int/
immunization/newsroom/Measles_Rubella_StrategicPlan_2012_2020.pdf (accessed
April 30, 2012).
4 WHO. Rubella vaccines: WHO position paper. Wkly Epidemiol Rec 2011; 86: 301–16.
5 Centers for Disease Control and Prevention. Measles outbreaks and progress toward measles preelimination—African region, 2009–2010. MMWR Morb Mortal Wkly Rep 2011; 60: 374–78.
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