Analysis of the yearly transition function in measles disease modeling.

Globally, there were an estimated 9.8 million measles cases and 207 500 measles deaths in 2019. As the effort to eliminate measles around the world continues, modeling remains a valuable tool for public health decision-makers and program implementers. This study presents a novel approach to the use of a yearly transition function that formulates mathematically the vaccine schedules for different age groups while accounting for the effects of the age of vaccination, the timing of vaccination, and disease seasonality on the yearly number of measles cases in a country. The methodology presented adds to an existing modeling framework and expands its analysis, making its utilization more adjustable for the user and contributing to its conceptual clarity. This article also adjusts for the temporal interaction between vaccination and exposure to disease, applying adjustments to estimated yearly counts of cases and the number of vaccines administered that increase population immunity. These new model features provide the ability to forecast and compare the effects of different vaccination timing scenarios and seasonality of transmission on the expected disease incidence. Although the work presented is applied to the example of measles, it has potential relevance to modeling other vaccine-preventable diseases.

Mapping the distribution of zero-dose children to assess the performance of vaccine delivery strategies and their relationships with measles incidence in Nigeria.

Geographically precise identification and targeting of populations at risk of vaccine-preventable diseases has gained renewed attention within the global health community over the last few years. District level estimates of vaccination coverage and corresponding zero-dose prevalence constitute a potentially useful evidence base to evaluate the performance of vaccination strategies. These estimates are also valuable for identifying missed communities, hence enabling targeted interventions and better resource allocation. Here, we fit Bayesian geostatistical models to map the routine coverage of the first doses of diphtheria-tetanus-pertussis vaccine (DTP1) and measles-containing vaccine (MCV1) and corresponding zero-dose estimates in Nigeria at 1x1 km resolution and the district level using geospatial data sets. We also map MCV1 coverage before and after the 2019 measles vaccination campaign in the northern states to further explore variations in routine vaccine coverage and to evaluate the effectiveness of both routine immunization (RI) and campaigns in reaching zero-dose children. Additionally, we map the spatial distributions of reported measles cases during 2018 to 2020 and explore their relationships with MCV zero-dose prevalence to highlight the public health implications of varying performance of vaccination strategies across the country. Our analysis revealed strong similarities between the spatial distributions of DTP and MCV zero dose prevalence, with districts with the highest prevalence concentrated mostly in the northwest and the northeast, but also in other areas such as Lagos state and the Federal Capital Territory. Although the 2019 campaign reduced MCV zero-dose prevalence substantially in the north, pockets of vulnerabilities remained in areas that had among the highest prevalence prior to the campaign. Importantly, we found strong correlations between measles case counts and MCV RI zero-dose estimates, which provides a strong indication that measles incidence in the country is mostly affected by RI coverage. Our analyses reveal an urgent and highly significant need to strengthen the country's RI program as a longer-term measure for disease control, whilst ensuring effective campaigns in the short term.

Vaccine coverage and measles incidence in Northern Brazil / Cobertura vacinal e incidência de sarampo na Região Norte do Brasil

Introduction: measles is an immunopreventable viral disease, acute exanthematous and extremely transmissible. Infection occurs directly, from person to person, through respiratory secretions. The measles vaccine is low-cost and effective, but measles still affects around 40 million people worldwide and is responsible for at least 800,000 deaths, mainly in developing countries.Objective: to analyze vaccination coverage and measles incidence in Northern Brazil.Methods: this is an ecological study. Secondary data were used regarding vaccination coverage of the viral double, viral triple and viral tetra and incidence of measles in residents in the States of the Northern Region, Brazil, from 2010 to 2018.Results: confirmed measles cases in 2010 to 2018 in the Northern region of Brazil it registered 10,249, were reported in Amazonas (95.65%), Roraima (3.53%), Pará (0.80%) and Rondônia (0.02%). Outbreaks of measles cases in the Northern Region were reported in 2018, the highest incidence rate was in Amazonas with 237.7. Vaccination coverage in the North Region varied between the lowest rate in 2013 with 56.88% and the highest vaccination coverage achieved in 2010, with 104.02%.Conclusion: it was possible to observe a reduction in vaccination coverage during the study period, not reaching the percentage recommended by the Ministry of Health and increasing the incidence of measles in the Northern Region of Brazil and these indicators are important to determine the strategies to be carried out by the National Program for Immunization and Epidemiological Surveillance.

Introdução: o sarampo é uma doença viral imunoprevenível, exantematosa aguda e extremamente transmissível. A infecção ocorre de forma direta, de pessoa a pessoa, por meio das secreções respiratórias. A vacina contra o sarampo é de baixo custo e efetiva, porém o sarampo ainda acomete cerca de 40 milhões de pessoas no mundo e é responsável por pelo menos 800 mil mortes, principalmente em países em desenvolvimento.Objetivo: analisar a cobertura vacinal e incidência de sarampo na Região Norte do Brasil.Método: trata-se de um estudo ecológico. Utilizou-se dados secundários referente a cobertura vacinal da dupla viral, tríplice viral e tetra viral e incidência de sarampo em residentes nos Estados da Região Norte, Brasil, no período de 2010 a 2018.Resultados: os casos confirmados de sarampo em 2010 a 2018 na região Norte do Brasil registrou 10.249, foram notificados no Amazonas (95,65%), Roraima (3,53%), Pará (0,80%) e Rondônia (0,02%). Os surtos de casos de sarampo na Região Norte foram notificados no ano de 2018, a maior taxa de incidência foi no Amazonas com 237,7. A cobertura vacinal da Região Norte variou entre o menor índice em 2013 com 56,88% e a maior cobertura vacinal alcançada em 2010, com 104,02%.Conclusão: foi possível observar uma redução da cobertura vacinal no período de estudo, não atingindo o percentual preconizado pelo Ministério da Saúde e aumentando a incidência de sarampo na Região Norte do Brasil e estes indicadores são importantes para determinar as estratégias a serem realizadas pelo Programa de Imunização e Vigilância Epidemiológica.

An analysis of the incidence of measles in Turkey since 1960.

BACKGROUND/AIM: The aims of this study were to evaluate measles incidence and the effect of elimination strategy interventions on the disease from 1960 to 2014 in Turkey. The administration of measles vaccine started in the rural regions in 1970; it was carried out as a campaign along with the National Vaccine Campaign in 1985, and it has been employed as combined measles, mumps, and rubella under the scope of the Measles Elimination Program (MEP) since 2006 in Turkey. While a dramatic decrease in the reporting of measles was observed between 2000 and 2010, the number of the cases has increased since 2011. MATERIALS AND METHODS: The time series of measles incidence was evaluated for possible structural changes with regression models using dummy variables, autocorrelated with error terms. RESULTS: The incidence of measles showed a statistically significant decline between 1985 and 1988 (P = 0.0072) and between 2005 and 2011 (P < 0.0001). However, a statistically significant increase in incidence was noted after 2013 (P = 0.0008). CONCLUSION: Over the last 54 years, the pattern of measles cases demonstrated a significant decline in incidence. However, the increase in incidence in 2013 should be carefully analyzed and interpreted in terms of the MEP.