Measles-containing vaccines in Brazil: Coverage, homogeneity of coverage and associations with contextual factors at municipal level

[The spatiotemporal diffusion of measles: an intra-urban analysis in Rio de Janeiro, Brazil]

This study aimed to analyze the profile of measles cases in the municipality of Rio de Janeiro, Brazil, from 2007 to 2021 and to describe their diffusion and cluster formation in epidemic years. Neighborhoods were considered as the units of this ecological study. A bivariate analysis of socioeconomic and epidemiological variables was conducted according to previous vaccination and hospitalization. Cluster and spatial diffusion analyses were performed by the SCAN screening method and Inverse Distance Weighting. Of the 774 confirmed cases, 57.6% were men, 72.9% were adults, and 63.7% self-identified as white. A higher proportion of previous vaccination occurred in white individuals and in those who were aged from 5 to 11 years. The stratum with higher schooling showed a higher proportion of previous vaccination. About 16.3% underwent hospitalization, with the highest risk occurring in those aged from 5 to 11 years and the lowest for those aged from 18 to 29 years old when compared to children up to one year of age. The first cases in the epidemic occurred in the Greater Tijuca area, then spreading to western and southern zones, showing hierarchical diffusion by relocation. The highest risk clusters were formed in the south and center zones. Findings confirm the change in the epidemiological profile of the disease and its diffusion pattern under the influence of the intra-urban hierarchy of the municipality, the neighborhoods of which with greater commerce and tourism act as initiators and diffusers of transmission. Such aspects should support control strategies, guiding immunization campaigns that address the most affected age groups and with custom actions in the areas of disease diffusion.

Measles, mumps and rubella vaccination coverage in capitals and interior region municipalities of Northeast Brazil: a household survey in a cohort of children born in 2017 and 2018

OBJECTIVE

To analyze measles, mumps, and rubella vaccination coverage among children up to 24 months old and factors associated with non-vaccination in a 2017-2018 live birth cohort, in state capitals and large interior region cities in Northeast Brazil.

METHODS

Population-based survey analyzing vaccination coverage and sociodemographic factors through logistic regression.

RESULTS

For 12,137 children, vaccination coverage was 79.3% (95%CI 76.5;81.8), and the dropout rate was 10.6%. Association with non-vaccination: socioeconomic stratum A (OR-a 1.29; 95%CI 1.10;1.50), living in the interior region (OR-a 1.22; 95%CI 1.07;1.39), no access to the Bolsa Família Program (OR-a 1.19, 95%CI 1.05;1.34), family income ≤BRL 1,000 (OR-a 1.17, 95%CI 1.03;1.31), mother not working (OR-a 1.28, 95%CI 1.15;1.42), >1 child per mother (OR-a 1.12, 95%CI 1.08;1.17), and no vaccination card (OR-a 10.69, 95%CI 6.27;18.20).

CONCLUSION

Low vaccination coverage and a high dropout rate in state capitals and municipalities in the interior region of Northeast Brazil.

MAIN RESULTS

79.3% vaccination coverage with incomplete vaccination associated with living in higher socioeconomic strata and in interior region municipalities, and children without vaccination records. High dropout rates in the state capitals Natal and João Pessoa.

IMPLICATIONS FOR SERVICES

Recognition of low coverage and factors associated with non-vaccination provides health services with relevant information with a view to planning strategic actions to increase measles, mumps and rubella vaccination coverage.

PERSPECTIVES

Low coverage and identification of non-vaccination indicate the importance of targeting actions in the Brazilian National Health System to achieve the targets recommended by the National Immunization Program, for populations in Northeast Brazil.

The Brazilian vaccine divide: How some municipalities were left behind in the Covid-19 vaccine coverage

This study aims to assess the progress of geographic, socioeconomic, and demographic disparities in Covid-19 vaccination coverage in Brazil over the first two years of the vaccination campaign. Data from the National Immunization Program Information System were used to estimate covid-19 vaccine coverage. Brazilian municipalities were divided into two groups based on their vaccine coverage for the booster dose. The first group comprised 20% of municipalities with the lowest coverage, while the second group (80% of municipalities) had higher coverage. The analysis was conducted separately for four age groups: 5-11, 12-17, 18-59, and 60+. Explanatory variables included socioeconomic and health services indicators. Crude and adjusted logistic regression models were used to estimate the probability of a municipality being among those with the worst vaccination coverage according to the categories of exploratory variables. Between January/2021 and December/2022, Brazil administered 448.2 million doses of the covid-19 vaccine. The booster vaccination coverage varied from 24.8% among adolescents to 79.7% among the elderly. The difference between the group with the highest and lowest coverage increased during the national vaccination campaign. Municipalities with lower education levels, higher proportion of Black population, higher Gini index, and worse health service indicators had a greater likelihood of having lower vaccination coverage. High and increasing levels of inequality in Covid-19 vaccination were observed in Brazil across all age groups during the vaccination campaign in 2021-2022.

Municipality-level measles, mumps, and rubella (MMR) vaccine coverage and deprivation in Brazil: A nationwide ecological study, 2006 to 2020

To better understand the declining rates of routine childhood vaccination in Brazil, we investigated the association between measles, mumps, and rubella (MMR) first dose vaccine coverage and deprivation at the municipality level. Using routinely collected data from 5565 Brazilian municipalities from 2006 to 2020, we investigated the association between municipality-level MMR vaccine first dose coverage (i.e., as a continuous variable and as a percentage of municipalities attaining the 95% target coverage) in relation to quintiles of municipality-level deprivation, measured by the Brazilian Deprivation Index (Índice Brasileiro de Privação, IBP), and geographic regions. From 2006 to 2020, the mean municipality-level MMR vaccine coverage declined across all deprivation quintiles and regions of Brazil, by an average of 1.2% per year. The most deprived quintile of municipalities had higher coverage on average, but also the steepest declines in coverage (i.e., an annual decline of 1.64% versus 0.61% in the least deprived quintile) in the period of 2006-2020, and the largest drop in coverage at the beginning of the COVID-19 pandemic (2019-2020). Across all deprivation quintiles and regions (except for the Southeast region), less than 50% of municipalities in Brazil met the 95% MMR coverage target in 2020.The decrease in MMR first dose vaccine coverage in Brazil is widespread, but steeper declines have been observed in the most deprived municipalities. To promote vaccine equity and prevent future outbreaks, further research is urgently needed to understand the causal mechanisms underlying the observed associations between municipality-level MMR vaccine coverage and deprivation.

Measles vaccination in Brazil: where have we been and where are we headed?

Abstract The re-emergence of vaccine-preventable diseases due to the decline in vaccine coverage (VC) has been documented in several countries. The objective was to analyze the VC, the homogeneity of VC, and measles cases in Brazil from 2011 to 2021, focusing on the period of the COVID-19 pandemic, its temporal trend, space-time distribution, and factors associated with clusters of lower VC. This is an ecological study on measles VC (dose 1), with methods of interrupted time series and evaluation of spatio-temporal disposition, through the sweep test to identify clusters of VC. Starting in 2015, we observe a progressive decline in VC and homogeneity, with an accentuation after 2020, in all regions, particularly in the North and Northeast. Low VC clusters were associated with worse human development indicators, social inequality, and less access to the Family Health Strategy. In Brazil, the pandemic intensified health inequalities with low VC of measles in socially more vulnerable and unequal municipalities. There is a risk of virus circulation, however, the challenge of strengthening primary care, improving health communication and guaranteeing access to the vaccine, reducing missed opportunities for vaccination and vaccine hesitancy, is highlighted.

Measles vaccination in Brazil: where have we been and where are we headed?

The re-emergence of vaccine-preventable diseases due to the decline in vaccine coverage (VC) has been documented in several countries. The objective was to analyze the VC, the homogeneity of VC, and measles cases in Brazil from 2011 to 2021, focusing on the period of the COVID-19 pandemic, its temporal trend, space-time distribution, and factors associated with clusters of lower VC. This is an ecological study on measles VC (dose 1), with methods of interrupted time series and evaluation of spatio-temporal disposition, through the sweep test to identify clusters of VC. Starting in 2015, we observe a progressive decline in VC and homogeneity, with an accentuation after 2020, in all regions, particularly in the North and Northeast. Low VC clusters were associated with worse human development indicators, social inequality, and less access to the Family Health Strategy. In Brazil, the pandemic intensified health inequalities with low VC of measles in socially more vulnerable and unequal municipalities. There is a risk of virus circulation, however, the challenge of strengthening primary care, improving health communication and guaranteeing access to the vaccine, reducing missed opportunities for vaccination and vaccine hesitancy, is highlighted.

Reduced Prevalence of Measles Antibodies in a Cohort of Brazilian Children under 15 Years of Age

Measles is a highly contagious acute febrile disease responsible for sporadic but explosive outbreaks worldwide. Although it was considered eliminated from the Americas, the disease reemerged in 2017. This reemergence was linked to reduced immunization rates. Vaccination, early identification of cases, and blocking of the transmission chain are the most effective tools to combat measles, for which there is not a specific antiviral treatment. In this Brazilian prospective cross-sectional study, we investigated the prevalence of measles antibodies in children, a population vulnerable to significant morbidity and mortality from exposure to infection. Between December 2018 to November 2019, blood samples from 252 children were collected and assessed for the presence of measles-specific IgG antibodies and an overall prevalence of 75.8% was observed. We further stratified the cohort into age subgroups, none of which exhibited antibody presence levels above the herd immunity threshold of 94%. Moreover, the calculated number of secondary cases resulting from a case in any age group ranged from 3 to 4, demonstrating that even with partial vaccination coverage this disease is still concerning and highly transmissible. Despite global warnings about measles and previous efforts to combat the advance of the disease, data on antibody prevalence and vaccination coverage in several countries are still concerning and indicate that significant parts of the population could be affected. Seroprevalence studies like this one are important to highlight actual epidemiological conditions and emphasize the need for additional strategies to encourage immunization and avoid the potential impacts of measles, particularly in children who can be severely affected.

Vaccination coverage and adherence to a dengue vaccination program in the state of Paraná, Brazil

The success of vaccination programs depends on the level of acceptance of the vaccine to achieve high vaccine coverage rates (VCR). Vaccine hesitancy is a challenge, especially concerning new vaccines. Dengue vaccine, Dengvaxia®, was licensed in Brazil in 2015 and implemented, in a pioneering publicly-funded initiative in the state of Paraná, between 2016 and 2018. The vaccination program took place in five phases in the 30 municipalities most affected by dengue in the state, targeting individuals from nine to 44 years-old in two cities and from 15 to 27 years-old in the other 28 municipalities, totaling a target population of 500,000 individuals. A cross-sectional descriptive study was carried out to assess VCR and adherence to the dengue vaccine in this program. VCR, dropout ratio (DR), and compliance with the vaccination schedule (CVS) were analyzed by sex, age group, and municipality size. A total of 302,603 individuals (60.5%) received ≥ 1 dose, 44.2% received ≥ 2 doses, and 28.6% 3 doses. The DR was 52.8%. Among individuals who started vaccination, 40.6% achieved CVS. The highest VCR, highest CVS, and lowest DR occurred in the age group from 9 to 14 years old and from 28 to 44 years old and in smaller municipalities. A greater proportion of men started vaccination (male 64.0%; female 57.1%) however, the DR was higher in men (male 55.4%; female 49.9%), and a higher percentage of women completed the vaccination schedule according to the recommendations (CVS male 37.8%; female 43.6%). Differences were noted in the CVS according to the initial phase of the program (first phase 50.8%; second phase 18.8%). The heterogeneity in vaccine uptake and compliance according to sex, age, and municipality size suggests the need for differentiated strategies to address challenges with new and multiple-dose vaccines.

Measles vaccination among children in border areas of Yunnan Province, Southwest China

BACKGROUND

Border areas are at high risk of measles epidemics. This study aimed to evaluate the effectiveness of the implementation of the routine two-dose measles containing vaccine (MCV) program in border counties of Southwest China.

METHODS

Data used in the study were derived from a cross-sectional survey among 1,467 children aged 8 to 84 months from five border counties of Yunnan Province, Southwest China in 2016. The participants were recruited using a multistage sampling method. Primary guardians of the children were interviewed to collect information on vaccination history, socio-economic status, and knowledge about immunization. Both coverage and timely coverage for the first (MCV1) and the second (MCV2) dose of MCV were calculated. The Kaplan-Meier method was performed to estimate the cumulative coverage of MCV, and Log-rank tests were adopted to compare the differences across counties and birth cohorts. Univariate and multivariate logistic regression models were used to investigate the predictors of delayed MCV1 vaccination.

RESULTS

The coverage for MCV1 and MCV2 were 97.5% and 93.4%, respectively. However, only 63.8% and 84.0% of the children received MCV1 or MCV2 on time. Significant differences in the cumulative coverage were detected across counties and birth cohorts. Results of the multivariate logistic regression analysis indicated that children whose primary guardian knew the schedule of MCV were less likely to receive MCV1 late (OR = 0.63, P<0.01). For the guardians, doctors at vaccination units were the primary and also the most desired source of vaccination information.

CONCLUSIONS

Although the coverage for MCV is high in border areas of Southwest China, the timeliness of MCV vaccination seems suboptimal. Tailored information from local health professionals may help to reduce untimely vaccination.