Evaluating vaccination policies to accelerate measles elimination in China: a meta-population modelling study
| Autor: | James L. Goodson, Qiru Su, Zhilan Feng, Chunxiang Fan, Lance E. Rodewald, Hong Yang, John W. Glasser, Zijian Feng, Ning Wen, Huaqing Wang, Lixin Hao, Chao Ma, Z D Yin |
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| Rok vydání: | 2019 |
| Předmět: |
Adult
Male China Adolescent Epidemiology Cross-sectional study Measles Vaccine 030231 tropical medicine Models Biological Measles Article Young Adult 03 medical and health sciences 0302 clinical medicine Humans Medicine 030212 general & internal medicine Young adult Child Aged Disease surveillance business.industry Health Policy Vaccination Infant Newborn Infant General Medicine Middle Aged medicine.disease Cross-Sectional Studies Logistic Models Immunization Vaccination policy Child Preschool Communicable Disease Control Female Disease Susceptibility Measles vaccine business Demography |
| Zdroj: | Int J Epidemiol |
| ISSN: | 1464-3685 0300-5771 |
| DOI: | 10.1093/ije/dyz058 |
| Popis: | Background Measles is among the most highly infectious human diseases. By virtue of increasingly effective childhood vaccination, together with targeted supplemental immunization activities (SIAs), health authorities in the People’s Republic of China have reduced measles’ reproduction number from about 18 to 2.3. Despite substantial residual susceptibility among young adults, more in some locales than others, sustained routine childhood immunization likely would eliminate measles eventually. To support global eradication efforts, as well as expedite morbidity and mortality reductions in China, we evaluated alternative SIAs via mechanistic mathematical modelling. Methods Our model Chinese population is stratified by immune status (susceptible to measles infection; infected, but not yet infectious; infectious; and recovered or immunized), age (0, 1–4, 5–9, …, 65+ years) and location (31 provinces). Contacts between sub-populations are either empirical or a mixture of preferential and proportionate with respect to age and decline exponentially with distance between locations at age-dependent rates. We estimated initial conditions and most parameters from recent cross-sectional serological surveys, disease surveillance and demographic observations. Then we calculated the reproduction numbers and gradient of the effective number with respect to age- and location-specific immunization rates. We corroborated these analytical results by simulating adolescent and young adult SIAs using a version of our model in which the age-specific contact rates vary seasonally. Results Whereas the gradient indicates that vaccinating young adults generally is the optimal strategy, simulations indicate that a catch-up campaign among susceptible adolescent schoolchildren would accelerate elimination, with timing dependent on uptake. Conclusions These results are largely due to indirect effects (i.e. fewer infections than immunized people might otherwise cause), which meta-population models with realistic mixing are uniquely capable of reproducing accurately. |
| Databáze: | OpenAIRE |
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