Immunity Gaps Research Articles

Hepatitis B Virus Immunity Gap: A Six-Year Laboratory Data Review of Hepatitis B Serological Profiles in Gauteng Province, South Africa.

In 1995, the hepatitis B vaccine in South Africa was incorporated into the childhood expanded programme of immunization. We report on immunity gaps of laboratory-based hepatitis B virus (HBV) among patients in public facilities in Gauteng Province from 1st January 2014 to 31st December 2019. Methodology. We analyzed HBV serological data extracted from the National Health Laboratory Services Central Data Warehouse (NHLS CDW). A descriptive analysis was performed for hepatitis B surface antigen (HBsAg), antibodies to HBV core (anti-HBc) total, anti-HBc IgM, and antibodies to HBV surface antigen (anti-HBs) according to annual distribution, age groups, and sex. The HBsAg positivity rate was 7.0% (75,596/1,095,561; p=0.001): 7.4% (96,532/944,077) in the 25 years and over age group and 4.0% (358/9,268 and 325/10,864) in the under 5 and 13-24 year age groups. The positivity rates of the other HBV serological markers were as follows: anti-HBc total was 37.0% (34,377/93,711; p < 0.001), anti-HBc IgM was 2.4% (5,661/239,237; p=0.05), and anti-HBs was 37.0% (76,302/206,138; p ≤ 0.001). Naturally acquired HBV immunity was detected in 25.7% (11,188/43,536) of patients in the 25 years and over age group, and 9.7% and 8.2% (113/1,158 and 541/6,522) among those under 5 years and 13-24 year age group, respectively (p < 0.001). Vaccine-induced immunity was 56.6% (656/1,158) in children under 5 years and 10.2% (4,425/43,536) among those 25 years and above (p < 0.001). Fifty-six percent (29,404/52,581) of patients were HBV seronegative; predominantly among patients in the 13-24 year age group (60.6%; (3,952/6,522)) and 25 years and over (56.3% (24,524/43,536)) (p=<0.001). The HBV infection seroprevalence remains high in South Africa, with Gauteng province having high intermediate endemicity. However, the HBV immunity gap has shifted from younger children to older children and adults.

Immunity Against SARS-CoV-2 in the German Population.

Early during the SARS-CoV-2 pandemic, national population-based seroprevalence surveys were conducted in some countries; however, this was not done in Germany. In particular, no seroprevalence surveys were planned for the summer of 2022. In the context of the IMMUNEBRIDGE project, the GUIDE study was carried out to estimate seroprevalence on the national and regional levels. To obtain an overview of the population-wide immunity against SARS-CoV-2 among adults in Germany that would be as statistically robust as possible, serological tests were carried out using self-sampling dried blood spot cards in conjunction with surveys, one by telephone and one online. Blood samples were analyzed for the presence of antibodies to the S and N antigens of SARS-CoV-2. Among the 15 932 participants, antibodies to the S antigen were detected in 95.7%, and to the N antigen in 44.4%. In the higher-risk age groups of persons aged 65 and above and persons aged 80 and above, anti-S antibodies were found in 97,4% and 98.8%, respectively. Distinct regional differences in the distribution of anti-S and anti-N antibodies emerged. Immunity gaps were found both regionally and in particular subgroups of the population. High anti-N antibody levels were especially common in eastern German states, and high anti-S antibody levels in western German states. These findings indicate that a large percentage of the adult German population has formed antibodies against the SARS-CoV-2 virus. This will markedly lower the probability of an overburdening of the health care system by hospitalization and high occupancy of intensive care units due to future SARS-CoV-2 waves, depending on the viral characteristics of then prevailing variants.

Mothers’ knowledge, attitude, and behavior regarding child immunization, and the association with child immunization status in Medan City during the COVID-19 pandemic

BackgroundThe COVID-19 pandemic has caused disruption to healthcare access worldwide and has impacted basic childhood immunization services. A decline in immunization coverage can cause immunity gaps and lead to outbreaks of vaccine-preventable diseases. Our study evaluated the association between mothers’ knowledge, attitude, and behavior regarding immunization and child immunization status during the COVID-19 pandemic in Medan, Indonesia. MethodsAn analytical cross-sectional study was conducted from April to November 2021. Mothers with children aged 0–12 months were interviewed about their knowledge, attitude, and behavior regarding immunization, and their child's immunization status. ResultsOf 196 participants, 46.5% had low knowledge on immunization, 41.3% had a negative attitude, and 20.4% had negative behavior. Only 62.8% of participants had children with a complete vaccination status, and mothers with moderate knowledge (OR 2.65, 95% CI 1.08–6.61), negative attitude (OR 5.33, 95% CI 2.71–10.59), and negative behavior (OR 7.88, 95% CI 3.36–19.47) were more likely to not vaccinate their children. ConclusionMothers’ attitude, behavior, and educational background were associated with child immunization status. Recovery efforts to improve immunization coverage are urgently needed, and should include efforts to reduce mothers’ hesitancy regarding child vaccination during the pandemic.

Vaccine Preventable Disease Seroprevalence in a Nationwide Assessment of Timor-Leste (VASINA-TL): study protocol for a population-representative cross-sectional serosurvey

IntroductionHistoric disruption in health infrastructure combined with data from a recent vaccine coverage survey suggests there are likely significant immunity gaps to vaccine preventable diseases and high risk of outbreaks...

Analysis of population immunity to poliovirus following cessation of trivalent oral polio vaccine.

The global withdrawal of trivalent oral poliovirus vaccine (OPV) (tOPV, containing Sabin poliovirus strains serotypes 1, 2 and 3) from routine immunization, and the introduction of bivalent OPV (bOPV, containing Sabin poliovirus strains serotypes 1 and 3) and trivalent inactivated poliovirus vaccine (IPV) into routine immunization was expected to improve population serologic and mucosal immunity to types 1 and 3 poliovirus, while population mucosal immunity to type 2 poliovirus would decline. However, over the period since tOPV withdrawal, the implementation of preventive bOPV supplementary immunization activities (SIAs) has decreased, while outbreaks of type 2 circulating vaccine derived poliovirus (cVDPV2) have required targeted use of monovalent type 2 OPV (mOPV2). We develop a dynamic model of OPV-induced immunity to estimate serotype-specific, district-level immunity for countries in priority regions and characterize changes in immunity since 2016. We account for the changes in routine immunization schedules and varying implementation of preventive and outbreak response SIAs, assuming homogenous coverages of 50% and 80% for SIAs. In areas with strong routine immunization, the switch from tOPV to bOPV has likely resulted in gains in population immunity to types 1 and 3 poliovirus. However, we estimate that improved immunogenicity of new schedules has not compensated for declines in preventive SIAs in areas with weak routine immunization. For type 2 poliovirus, without tOPV in routine immunization or SIAs, mucosal immunity has declined nearly everywhere, while use of mOPV2 has created highly heterogeneous population immunity for which it is important to take into account when responding to cVDPV2 outbreaks. The withdrawal of tOPV and declining allocations of resources for preventive bOPV SIAs have resulted in reduced immunity in vulnerable areas to types 1 and 3 poliovirus and generally reduced immunity to type 2 poliovirus in the regions studied, assuming homogeneous coverages of 50% and 80% for SIAs. The very low mucosal immunity to type 2 poliovirus generates substantially greater risk for further spread of cVDPV2 outbreaks. Emerging gaps in immunity to all serotypes will require judicious targeting of limited resources to the most vulnerable populations by the Global Polio Eradication Initiative (GPEI).

Challenges Addressing Inequalities in Measles Vaccine Coverage in Zambia through a Measles-Rubella Supplementary Immunization Activity during the COVID-19 Pandemic.

Measles-rubella supplementary immunization activities (MR-SIAs) are conducted to address inequalities in coverage and fill population immunity gaps when routine immunization services fail to reach all children with two doses of a measles-containing vaccine (MCV). We used data from a post-campaign coverage survey in Zambia to measure the proportion of measles zero-dose and under-immunized children who were reached by the 2020 MR-SIA and identified reasons associated with persistent inequalities following the MR-SIA. Children between 9 and 59 months were enrolled in a nationally representative, cross-sectional, multistage stratified cluster survey in October 2021 to estimate vaccination coverage during the November 2020 MR-SIA. Vaccination status was determined by immunization card or through caregivers' recall. MR-SIA coverage and the proportion of measles zero-dose and under-immunized children reached by MR-SIA were estimated. Log-binomial models were used to assess risk factors for missing the MR-SIA dose. Overall, 4640 children were enrolled in the nationwide coverage survey. Only 68.6% (95% CI: 66.7%, 70.6%) received MCV during the MR-SIA. The MR-SIA provided MCV1 to 4.2% (95% CI: 0.9%, 4.6%) and MCV2 to 6.3% (95% CI: 5.6%, 7.1%) of enrolled children, but 58.1% (95% CI: 59.8%, 62.8%) of children receiving the MR-SIA dose had received at least two prior MCV doses. Furthermore, 27.8% of measles zero-dose children were vaccinated through the MR-SIA. The MR-SIA reduced the proportion of measles zero-dose children from 15.1% (95% CI: 13.6%, 16.7%) to 10.9% (95% CI: 9.7%, 12.3%). Zero-dose and under-immunized children were more likely to miss MR-SIA doses (prevalence ratio (PR): 2.81; 95% CI: 1.80, 4.41 and 2.22; 95% CI: 1.21 and 4.07) compared to fully vaccinated children. The MR-SIA reached more under-immunized children with MCV2 than measles zero-dose children with MCV1. However, improvement is needed to reach the remaining measles zero-dose children after SIA. One possible solution to address the inequalities in vaccination is to transition from nationwide non-selective SIAs to more targeted and selective strategies.

Seroprotection against tetanus in southern Vietnam.

Ongoing tetanus cases and sporadic outbreaks of vaccine-preventable diseases associated with routine vaccination programmes remain problems in many low and middle-income countries, including Vietnam. With no human-to-human transmission or natural immunity, tetanus antibody levels indicate both individual risk of tetanus and gaps in vaccination programmes. To investigate gaps in immunity to tetanus in Vietnam, a country with a historically high level of tetanus vaccination coverage, tetanus antibodies were measure by ELISA from samples selected from a long-term serum bank, established for the purposes of general-population seroepidemiological investigations in southern Vietnam. Samples were selected from 10 provinces, focussing on age-groups targeted by national vaccination programmes for infants and pregnant women (Expanded Programme on Immunization, EPI, and Maternal and Neonatal Tetanus, MNT). Antibodies were measured from a total of 3864 samples. Highest tetanus antibody concentrations occurred in children under 4years old, over 90% of whom had protective levels. Approximately 70% of children aged 7-12years had protective antibody concentrations although there was variation among provinces. For infants and children, there were no significant differences in tetanus protection between males and females, but for adults aged 20-35years, in five of the ten provinces surveyed, protection against tetanus was higher in females (p<0.05) who are eligible for booster doses under the MNT programme. In seven of ten provinces, antibody concentrations were inversely related to age (p<0.01) and protection of older individuals was generally low. Widespread immunity to tetanus toxoid is seen in infants and young children consistent with the high coverage rates reported for diptheria tetanus toxoid and pertussis (DTP) in Vietnam. However, the lower antibody concentrations seen in older children and men suggest reduced immunity to tetanus in populations not targeted by EPI and MNT programmes.

Immunity Against Measles in Urban Refugee Children, Adolescents, and Young Adults in Eastleigh, Kenya

Background: Kenya has made progress towards the elimination of measles through routine and supplementary immunisation activities; however, sporadic outbreaks still occur. Studies on measles seroprevalence in Kenya are few and extensive analysis of refugee and migrant populations’ immunity against measles is lacking. This cross-sectional study aimed at assessing the presence of immunity against measles in children, adolescents and young adults living in the high urban refugee area of Eastleigh Nairobi, Kenya. Method: A total of 384 samples serum samples were collected from consenting respondents and tested for measles IgG antibodies. Syncytium Inhibition Assay, a neutralisation assay was used to determine functionality. The establishment of herd immunity was calculated using the Plans- Rubio formulae. Results: Seropositive rate for all respondents were 84.38%, while equivocal and negative were 4.95% and 10.68%, respectively. None of the factors analysed was a significant predictor of positive measles antibodies. 87.76% of the total sera were neutralising, while 12.23 % were negative. There was a significant correlation between the neutralisation titres and ELISA values. Conclusion: This study highlights age-specific measles immunity gaps in an urban refugee population. Although measles antibodies are present in all age groups, none has established herd immunity. In order to avert outbreaks in the study population, it is necessary to direct immunisation interventions to increase the measles antibody prevalence to recommended levels.

Exploring epidemic voluntary vaccinating behavior based on information-driven decisions and benefit-cost analysis

A complex dynamic interplay exists between epidemic transmission and vaccination, which is significantly influenced by human behavioral responses. We construct a research framework combining both the function modeling of the cumulative global COVID-19 information and limited individuals’ information processing capacity employing the Gompertz model for growing processes. Meanwhile, we built a function representing the decision to get vaccinated following benefit-cost analysis considered the choices made by people in each scenario have an influence from altruism, free-riding and immunity escaping capacity. Through the mean-field calculation analysis and using a fourth-order Runge-Kutta method with constant step size, we obtain plots from numerical simulations.We found that only when the total number of infectious individuals proves sufficient to reach and exceed a certain level will the individuals face a better trade-off in determining whether to get vaccinated against the diseases based on that information. Besides, authoritative media have a higher decisive influence and efforts should be focused on extending the duration of vaccine protection, which is beneficial to inhibit the outbreaks of epidemics. Our work elucidates that reducing the negative payoff brought about by the free-riding behavior for individuals or improving the positive payoff from the altruistic motivation helps to control the disease in cultures that value social benefits, vaccination willingness is generally stronger. We also note that at a high risk of infection, the decision of vaccination is highly correlated with global epidemic information concerning COVID-19 infection, while at times of lower risk, it depends on the game theoretic vaccine strategy. The findings demonstrate that improving health literacy, ensuring open and transparent information on vaccine safety and efficacy as a public health priority can be an effective strategy for mitigating inequalities in health education, as well as alleviating the phenomenon that immunity escaping abilities is more likely to panic by populations with high levels of education. In addition, prosocial nudges are great ways to bridge these immunity gaps that can contribute to implementing government public health control measures, creating a positive feedback loop.

Methodological approaches to optimize multiplex oral fluid SARS-CoV-2 IgG assay performance and correlation with serologic and neutralizing antibody responses

BackgroundOral fluid (hereafter, saliva) is a non-invasive and attractive alternative to blood for SARS-CoV-2 IgG testing; however, the heterogeneity of saliva as a matrix poses challenges for immunoassay performance. ObjectivesTo optimize performance of a magnetic microparticle-based multiplex immunoassay (MIA) for SARS-CoV-2 IgG measurement in saliva, with consideration of: i) threshold setting and validation across different MIA bead batches; ii) sample qualification based on salivary total IgG concentration; iii) calibration to U.S. SARS-CoV-2 serological standard binding antibody units (BAU); and iv) correlations with blood-based SARS-CoV-2 serological and neutralizing antibody (nAb) assays. MethodsThe salivary SARS-CoV-2 IgG MIA included 2 nucleocapsid (N), 3 receptor-binding domain (RBD), and 2 spike protein (S) antigens. Gingival crevicular fluid (GCF) swab saliva samples were collected before December 2019 (n = 555) and after molecular test-confirmed SARS-CoV-2 infection from 113 individuals (providing up to 5 repeated-measures; n = 398) and used to optimize and validate MIA performance (total n = 953). Combinations of IgG responses to N, RBD and S and total salivary IgG concentration (μg/mL) as a qualifier of nonreactive samples were optimized and validated, calibrated to the U.S. SARS-CoV-2 serological standard, and correlated with blood-based SARS-CoV-2 IgG ELISA and nAb assays. ResultsThe sum of signal to cutoff (S/Co) to all seven MIA SARS-CoV-2 antigens and disqualification of nonreactive saliva samples with ≤15 μg/mL total IgG led to correct classification of 62/62 positives (sensitivity [Se] = 100.0%; 95% confidence interval [CI] = 94.8%, 100.0%) and 108/109 negatives (specificity [Sp] = 99.1%; 95% CI = 97.3%, 100.0%) at 8-million beads coupling scale and 80/81 positives (Se = 98.8%; 95% CI = 93.3%, 100.0%] and 127/127 negatives (Sp = 100%; 95% CI = 97.1%, 100.0%) at 20-million beads coupling scale. Salivary SARS-CoV-2 IgG crossed the MIA cutoff of 0.1 BAU/mL on average 9 days post-COVID-19 symptom onset and peaked around day 30. Among n = 30 matched saliva and plasma samples, salivary SARS-CoV-2 MIA IgG levels correlated with corresponding-antigen plasma ELISA IgG (N: ρ = 0.76, RBD: ρ = 0.83, S: ρ = 0.82; all p < 0.001). Correlations of plasma SARS-CoV-2 nAb assay area under the curve (AUC) with salivary MIA IgG (N: ρ = 0.68, RBD: ρ = 0.78, S: ρ = 0.79; all p < 0.001) and with plasma ELISA IgG (N: ρ = 0.76, RBD: ρ = 0.79, S: ρ = 0.76; p < 0.001) were similar. ConclusionsA salivary SARS-CoV-2 IgG MIA produced consistently high Se (> 98.8%) and Sp (> 99.1%) across two bead coupling scales and correlations with nAb responses that were similar to blood-based SARS-CoV-2 IgG ELISA data. This non-invasive salivary SARS-CoV-2 IgG MIA could increase engagement of vulnerable populations and improve broad understanding of humoral immunity (kinetics and gaps) within the evolving context of booster vaccination, viral variants and waning immunity.

Recovering from the Unprecedented Backsliding in Immunization Coverage: Learnings from Country Programming in Five Countries through the Past Two Years of COVID-19 Pandemic Disruptions.

Between 2020 and 2021, the COVID-19 pandemic severely strained health systems across countries, leaving millions without access to essential healthcare services. Immunization programs experienced a 'double burden' of challenges: initial pandemic-related lockdowns disrupted access to routine immunization services, while subsequent COVID-19 vaccination efforts shifted often limited resources away from routine services. The latest World Health Organization (WHO) and United Nations Children's Fund (UNICEF) estimates suggest that 25 million children did not receive routine vaccinations in 2021, six million more than in 2019 and the highest number witnessed in nearly two decades. Recovering from this sobering setback requires a united push on several fronts. Intensifying the catch-up of routine immunization services is critical to reach children left behind during the pandemic and bridge large immunity gaps in countries. At the same time, we must strengthen the resilience of immunization systems to withstand future pandemics if we hope to achieve the goals of Immunization Agenda 2030 to ensure vaccinations are available for everyone, everywhere by 2030. In this article, leveraging the key actions for sustainable global immunization progress as a framework, we spotlight examples of strategies used by five countries-Cambodia, Cameroon, Kenya, Nigeria, and Uganda-who have exhibited exemplar performance in strengthening routine immunization programs and restored lost coverage levels in the last two years of the COVID-19 pandemic. The contents of this article will be helpful for countries seeking to maintain, restore, and strengthen their immunization services and catch up missed children in the context of pandemic recovery and to direct their focus toward building back a better resilience of their immunization systems to respond more rapidly and effectively, despite new and emerging challenges.

Well Child Wednesdays: An interprofessional pilot-program to increase pediatric immunizations Post-COVID

BackgroundThe COVID-19 pandemic halted routine medical care, including well-child visits (WCVs) and immunizations. PurposeDescribe the development and impact of a multidisciplinary initiative on the number of WCVs and immunizations delivered in aftermath of the COVID-19 pandemic over a four week period between April 14, 2021 and May 5, 2021. MethodsStudent pharmacists (SP), family medicine residents (FMRs), and nurses within a family medicine practice in a medically underserved community, developed a program to increase the number of pediatric patients up-to-date on WCVs and immunizations. “Well-child Wednesdays” used adjusted staffing to conduct visits with patients behind on vaccines. The 4-week pilot program utilized SPs to identify immunization gaps in patients less than 12 years old following chart review and to coordinate scheduling. During the visit, FMRs completed the components of the well-child visit; immunization gaps were communicated to the nurse who, after review, administered needed immunizations. DiscussionOf 193 patient charts reviewed for immunization needs, 68 were not up-to-date on routine vaccines and 29 patients (mean age 5 years old, 58.6% male) were able to be reached and agreed to schedule a visit. Of these, 20 kept their appointment and a total of 69 vaccines were administered, with DTaP as the most common with 13 doses administered followed by Hepatitis A with 10 doses given. ConclusionsAn interprofessional immunization program was an effective strategy to address the decline in immunizations and WCVs as a result of COVID-19.

Essential childhood immunization in 43 low- and middle-income countries: Analysis of spatial trends and socioeconomic inequalities in vaccine coverage.

Globally, access to life-saving vaccines has improved considerably in the past 5 decades. However, progress has started to slow down and even reverse in recent years. Understanding subnational heterogeneities in essential child immunization will be critical for closing the global vaccination gap. We use vaccination information for over 220,000 children across 1,366 administrative regions in 43 low- and middle-income countries (LMICs) from the most recent Demographic and Health Surveys. We estimate essential immunization coverage at the national and subnational levels and quantify socioeconomic inequalities in such coverage using adjusted concentration indices. Within- and between-country variations are summarized via the Theil index. We use local indicator of spatial association (LISA) statistics to identify clusters of administrative regions with high or low values. Finally, we estimate the number of missed vaccinations among children aged 15 to 35 months across all 43 countries and the types of vaccines most often missed. We show that national-level vaccination rates can conceal wide subnational heterogeneities. Large gaps in child immunization are found across West and Central Africa and in South Asia, particularly in regions of Angola, Chad, Nigeria, Guinea, and Afghanistan, where less than 10% of children are fully immunized. Furthermore, children living in these countries consistently lack all 4 basic vaccines included in the WHO's recommended schedule for young children. Across most countries, children from poorer households are less likely to be fully immunized. The main limitations include subnational estimates based on large administrative divisions for some countries and different periods of survey data collection. The identified heterogeneities in essential childhood immunization, especially given that some regions consistently are underserved for all basic vaccines, can be used to inform the design and implementation of localized intervention programs aimed at eliminating child suffering and deaths from existing and novel vaccine-preventable diseases.

Driving Paediatric Vaccine Recovery in Europe

Childhood vaccination coverage has increased throughout Europe in recent decades. However, challenges persist in many areas within the European Union (EU), resulting in declining coverage rates in many countries in the period between 2010 and 2021. This general trend requires increased efforts to combat barriers around vaccination uptake. Thus, this article aims to summarise key learnings and trends in paediatric vaccination within the EU, with a focus on current challenges and enablers. Methodology is based on analysis of primary data, mainly vaccination coverage rates, as well as review and analysis of the select relevant literature, including peer-reviewed articles, academic research papers, official reports, policies, and other publicly available sources. For all vaccines assessed (DTP 1st dose, DTP 3rd dose, Hib3, HepB3, measles 1st dose, measles 2nd dose, and polio 3rd dose), a high degree of variation and fluctuation in coverage can be observed. There is a general trend of declining coverage in 2019 compared to 2010, with lower performing countries, such as Romania and Austria, showing increasingly severe coverage fluctuations between the years examined across the analysed vaccines. Evidence suggests that increasing both accessibility and information regarding vaccines are key enablers to vaccination uptake. Moreover, given the current challenges the EU is facing, crisis preparedness plans are pertinent to ensure immunity gaps do not further exacerbate the disruption of vaccination systems.

Decline in reported measles cases in Italy in the COVID-19 era, January 2020 – July 2022: The need to prevent a resurgence upon lifting non-pharmaceutical pandemic measures

From January 2020 to July 2022, 120 measles cases were reported to the Italian national surveillance system, of which 105 had symptom onset in 2020, nine in 2021 and six in the first seven months of 2022. This represents a sharp decline compared to the time period immediately preceding the COVID-19 pandemic, most likely due to the non-pharmaceutical interventions implemented to prevent SARS-CoV2 transmission. Of 105 cases reported in 2020, 103 acquired the infection before a national lockdown was instituted on 9 March 2020. Overall, one quarter of cases reported at least one complication. As non-pharmaceutical pandemic measures are being eased worldwide, and considering measles seasonality, infectiousness, and its potential severity, it is important that countries ensure high vaccination coverage and close immunity gaps, to avoid risk of future outbreaks.

Measles Serostatus in Mothers and Their Newborns in Antioquia, Colombia: Implications for Measles Elimination.

To describe the serostatus of measles IgG antibodies in pregnant women and newborns, placental transfer, and factors that determine being below the threshold of 150 mIU/mL, a cross-sectional study was conducted. Blood samples of 790 pregnant women at the time of delivery and 734 umbilical cord samples were analyzed from eight hospitals in the Aburrá Valley of Antioquia, Colombia. Measles IgG antibody measurement was performed with ELISA. The proportion of individuals with antibodies < 150 mIU/mL was 13.9% (95% CI: 12.2-15.8) in pregnant women and 11.1% (95% CI: 9.2-13.4) in newborns. The geometric mean of the antibody level of the pregnant women was 552 mIU/mL (95% CI: 504-605) and in the umbilical cord 662 mIU/mL (95% CI: 604-727). A positive correlation between pregnant woman and umbilical cord antibodies was found. The median ratio of measles IgG antibodies in umbilical cord/pregnant woman was 1.22 for all participants. A seroprevalence below the threshold of 150 mIU/mL was found in newborns whose mothers were born between 1983 and 1994, compared with those born before that period, when exposure to the wildtype virus was common (adjusted prevalence ratio: 3.6, 95% CI: 1.3-9.6). These findings suggest that there are gaps in measles immunity among women of childbearing age, before pregnancy. To close this immune gap and support efforts to maintain measles control, serological screening for measles antibodies should be routinely included in reproductive health and antenatal care programs to identify women without immunity who should be vaccinated before pregnancy or after delivery.

Desigualdades na cobertura vacinal infantil: potenciais lições do caso da Guiné-Bissau

Immunization is one of the main interventions responsible for the decline in under-5 mortality. This study aimed to assess full immunization coverage trends and related inequalities, according to wealth, area of residence, subnational regions, and maternal schooling level in Guinea-Bissau. Data from the 2006, 2014, and 2018 Guinea-Bissau Multiple Indicator Cluster Surveys (MICS) were analyzed. The slope index of inequality (SII) was estimated by logistic regression for wealth quintiles and maternal schooling level as a measure of absolute inequality. A linear regression model with variance-weighted least squares was used to estimate the annual change of immunization indicators at the national level and for the extremes of wealth, maternal schooling level, and urban-rural areas. Full immunization coverage increased by 1.8p.p./year (95%CI: 1.3; 2.3) over the studied period. Poorer children and children born to uneducated mothers were the most disadvantaged groups. Over the years, wealth inequality decreased and urban-rural inequalities were practically extinguished. In contrast, inequality of maternal schooling level remained unchanged, thus, the highest immunization coverage was among children born to the most educated women. This study shows persistent low immunization coverage and related inequalities in Guinea-Bissau, especially according to maternal schooling level. These findings reinforce the need to adopt equity as a main principle in the development of public health policies to appropriately reduce gaps in immunization and truly leave no one behind in Guinea-Bissau and beyond.

Mission Indradhanush and Intensified Mission Indradhanush-Success Story of India's Universal Immunization Program and the Role of Mann Ki Baat in Bridging the Immunization Gap.

Child immunization is crucial for reducing the morbidity and mortality associated with vaccine-preventable diseases (VPDs). The program grew over the years, however, progress towards full immunization coverage (FIC) remained slow, with only 44% of children fully immunized in 1992-1993, and 62% in 2015-2016, as reported in the National Family Health Survey. To address this challenge, Government of India launched Routine Immunization intensification drive- Mission Indradhanush (MI) in 2014, with the aim of achieving 90% FIC. The success of MI led to the launch of Intensified Mission Indradhanush (IMI) in 2017, with more intensive planning, monitoring, review, and inter-sectoral partnerships.

Vaccine hesitancy: An experience from an immunization clinic of a tertiary care hospital of Eastern Odisha

Introduction: Immunization-a successful and cost-effective measure-to protect children is facing the growing challenge of vaccine hesitancy (VH), especially for countries seeking to close the immunization gap. Objective: The objective of this study was to determine the prevalence of VH and its determinants. Methods: A cross-sectional study was conducted in an immunization clinic, KIMS, Bhubaneswar, from May to July 2019. Data were collected by interviewing parents accompanying their children. Parents were classified as pro-vaccine, vaccine-hesitant, or anti-vaccine on self-reports (as per fixed researcher-made operational definition). Of 117 participants contacted, 29 refused for any vaccine administration and were hence excluded, making a total sample of 88. Results: Of 88 participants, 39.8% were pro-vaccine and 60.2% vaccine-hesitant; the proportion of VH being 45.3%; although most pro-vaccine and hesitant parents agreed about the benefits of vaccinations. The mean age of the children was 3.65 ± 1.96 years. Family pediatricians were considered a reliable source of information by most pro-vaccine and hesitant parents (56.1% and 43.9%, respectively). The main factors which had a statistically significant association with VH were education of the father (P = 0.03), education of the mother (P = 0.036), and socioeconomic status (P = 0.0016). Conclusion: Vaccine safety is perceived as a concern by all parents, although more so by hesitant parents. Training health professionals and providing homogenous information about vaccination, in line with national recommendations can help in responding to their concerns.

Seroprevalence of poliovirus antibodies in Nigeria: refining strategies to sustain the eradication effort.

in 2016, a switch from trivalent oral poliovirus vaccine (OPV) (containing serotypes 1,2,3) to bivalent OPV (types 1,3) was implemented globally. We assessed the seroprevalence of poliovirus antibody levels in selected Nigerian states, before and after the switch, documented poliovirus type2 outbreak responses conducted and ascertained factors associated with immunity gaps based on seroprevalence rates. we conducted a secondary analysis of stored serum samples from the 2018 Nigeria National HIV/AIDS Indicator and Impact Survey. Serum from 1,185 children aged 0-119 months residing in one southern and four northern states were tested for serotype-specific PV neutralizing antibodies; seropositivity was a reciprocal titer ≥8. We conducted regression analysis to determine sociodemographic risk factors associated with low seroprevalence using SAS 9.4. children aged 24-119 months (pre-switch cohort) had seroprevalence against PV1, PV2, and PV3, of 97.3% (95% CI:96.4-98.2), 93.8% (95% CI:92.2-95.5), and 91.3% (95% CI:89.2-93.4), while children aged <24 months (post-switch) had seroprevalence of 86.0% (95% CI:81.2-90.8), 55.6% (95% CI: 47.7-63.4), and 77.2% (95% CI:71.0-83.4) respectively. Regression analysis showed age <24 months was associated with lower seroprevalence against all PV serotypes, (p<0.0001); females had lower seroprevalence against PV1 (p=0.0184) and PV2 (p=0.0354); northern states lower seroprevalence against PV1 (p=0.0039), while well-water source lower seroprevalence against PV3 (p=0.0288). this study showed high seroprevalence rates against PV 1, 2, and 3 in pre-switch children (aged 24-119 months). However, post-switch children (<24 months) had low immunity against PV2 despite outbreak responses. Strategies to increase routine immunization coverage and high-quality polio campaigns can increase immunity against polio virus.