Modelling measles re-emergence as a result of waning of immunity in vaccinated populations.
An age-structured mathematical model of measles transmission in a vaccinated population is used to simulate the shift from a population whose immunity is derived from natural infection to a population whose immunity is vaccine-induced. The model incorporates waning of immunity in a population of vaccinees that eventually will become susceptible to a milder form of vaccine-modified measles with a lower transmission potential than unvaccinated classical measles. Using current estimates of duration of vaccine-derived protection, measles would not be expected to re-emerge quickly in countries with sustained high routine vaccine coverage. However, re-emergence is possible to occur several decades after introduction of high levels of vaccination. Time until re-emergence depends primarily on the contagiousness of vaccine-modified measles cases in comparison to classical measles. Interestingly, in a population with a high proportion of vaccinees, vaccine-modified measles and classical measles would occur essentially in the same age groups. Although waning of humoral immunity in vaccinees is widely observed, re-emergence of measles in highly vaccinated populations depends on parameters for which better estimates are needed.
Laboratoire National de Santé, P.O. Box 1102, L-1011 Luxembourg, Luxembourg. joel.mossong@lns.etat.lu
Joël
J
Mossong
Claude P
CP
Muller
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D032541:Mass Vaccination; D008457:Measles / Q000453:epidemiology* / Q000276:immunology* / Q000635:transmission; D008458:Measles Vaccine / Q000276:immunology; D008875:Middle Aged; D008954:Models, Biological; D015233:Models, Statistical; D011153:Population
D008458:Measles Vaccine