Bradley F. Carlson

A population profile of measles susceptibility in Tianjin, China.

BACKGROUND Measles is a highly infectious illness requiring herd immunity of 95% to interrupt transmission. Measles is targeted for elimination in China, which has not reached elimination goals despite high vaccination coverage. We developed a population profile of measles immunity among residents aged 0-49 years in Tianjin, China. METHODS Participants were either from community population registers or community immunization records. Measles IgG antibody status was assessed using dried blood spots. We examined the association between measles IgG antibody status and independent variables including urbanicity, sex, vaccination, measles history, and age. RESULTS 2818 people were enrolled. The proportion measles IgG negative increased from 50.7% for infants aged 1 month to 98.3% for those aged 7 months. After 8 months, the age of vaccination eligibility, the proportion of infants and children measles IgG negative decreased. Overall, 7.8% of participants 9 months of age or older lacked measles immunity including over 10% of those 20-39 years. Age and vaccination status were significantly associated with measles IgG status in the multivariable model. The odds of positive IgG status were 0.337 times as high for unvaccinated compared to vaccinated (95% CI: 0.217, 0.524). CONCLUSIONS The proportion of persons in Tianjin, China immune to measles was lower than herd immunity threshold with less than 90% of people aged 20-39 years demonstrating protection. Immunization programs in Tianjin have been successful in vaccinating younger age groups although high immunization coverage in infants and children alone would not provide protective herd immunity, given the large proportion of non-immune adults.

Measles vaccine coverage and series completion among children 0-8 years of age in Tianjin China.

Background: The World Health Organization (WHO) targeted China for measles elimination by 2012. Although China made significant progress, transmission continues, warranting examination of China’s measles vaccination program. The World Health Organization recommends that children receive at least 2 doses of a measles containing vaccine (MCV) to ensure protection. In Tianjin, China, MCV is given in 3 doses: 8 months [measles vaccine (MV)], 18–24 months [measles–mumps–rubella (MMR)-1] and 5 years MMR-2). MMR-2 is important because of the young age for MV administration. This study describes MCV coverage, assesses administration timeliness and evaluates completion of the MCV series for children living in Tianjin, China. Methods: In July 2012, immunization records were selected from Tianjin’s Immunization Information Management System. Records were abstracted for children born from 2004 to 2011, who were aged 8 months or older. Descriptive statistics characterized the study population and assessed timeliness and coverage for each MCV dose. Results: We examined records of 205,982 children living in Tianjin, China. Among children who were age-appropriate for each vaccine, 98.6% received MV, 97.6% received MMR-1 and 76.9% received MMR-2. Of the children who were old enough to receive MMR-2, 78.8% received the complete series and 71.6% were fully immunized for measles by age 6 years. Conclusions: Tianjin has high rates of MV and MMR-1 coverage, with lower levels for MMR-2. Most children who completed the series did so on time. Maintaining high coverage and timely administration of MV and MMR-1 and increasing coverage of MMR-2 are necessary for China to attain the goal of national measles elimination.

Application of the revised WHO causality assessment protocol for adverse events following immunization in India

BACKGROUND In 2013, the World Health Organization (WHO) and CIOMS introduced a revised Causality Assessment Protocol (CAP) for Adverse Events following Immunization (AEFI). India is one of the first countries to adopt the revised CAP. This study describes the application of the revised CAP in India. METHODS We describe use of CAP by Indias AEFI surveillance program to assess reported AEFIs. Using publicly available results of causality assessment for reported AEFIs, we describe the results by demographic characteristics and review the trends for the results of the causality assessment. RESULTS A total of 771 reports of AEFI between January 2012 and January 2015, completed causality review by August 2016. The cases were reported as belonging to a cluster (54%; n=302), hospitalized or requiring hospitalization (41%; n=270), death (25%; n=195), or resulting in disability (0.4%; n=3). The most common combinations of vaccines leading to report of an AEFI were DTwP, Hepatitis B, and OPV (14%; n=106), followed by Pentavalent and OPV (13%; n=103), and JE vaccine (13%; n=101). Using the WHO Algorithm, most AEFI reports (89%, n=683) were classifiable. Classifiable AEFI reports included those with a consistent causal association (53%; n=407), an inconsistent causal association (29%; n=226) or were indeterminate causal association with implicated vaccine(s) or vaccination process (6.5%; n=50) (Fig. 1); 88 reports remained unclassifiable. CONCLUSIONS The revised CAP was informative and useful in classifying most of the reviewed AEFIs in India. Unclassifiable reports could be minimized with more complete information from health records. Improvements in causality assessment, and standardization in reporting between countries, can improve public confidence in vaccine system performance and identify important vaccine safety signals.

Factors Associated with Vaccination Status of Children Aged 12–48 Months in India, 2012–2013

Objectives India has more unvaccinated children than any other country despite provision of free vaccines through the government’s Universal Immunization Program. In this study, we calculated the proportion of children aged 12–48 months who were fully vaccinated, under-vaccinated, or who had not received any vaccines. Childhood, household, and sociocultural factors associated with under-vaccination and non-vaccination were evaluated. Methods Using data from India’s 4th District-level Health and Facility Survey, 2012–2013 (DLHS-4) and the 2012–2013 Annual Health Survey (AHS), we calculated the proportion of children who were non-vaccinated, under-vaccinated, or fully vaccinated with 1 dose of Bacillus Calmette–Guérin, 3 doses of oral polio vaccine, 3 doses of diphtheria–pertussis–tetanus, and 1 dose of measles-containing vaccine. The odds of full vaccination compared to non-vaccination and under-vaccination relative to various factors was assessed using a multivariable, multinomial logistic regression which accounted for survey design. Results Of 1,929,580 children aged 12–48 months, 59% were fully vaccinated, 34% were under-vaccinated, and 7% were non-vaccinated. Compared to children born in government institutions, children delivered in non-institutional settings with a skilled birth attendant present had higher odds of non-vaccination (OR 1.66) and those without a skilled attendant present had still greater odds of non-vaccination (OR 2.39) and under-vaccination (OR 1.11). Conclusions for Practice India’s vaccination rates among children aged 12–48 months remains unacceptably low. The Indian government should encourage institutional delivery or birthing with a skilled attendant to ensure women receive adequate health education through antenatal care that includes the importance of childhood vaccination.

Hygienic behaviors and risks for ascariasis among college students in Kabul, Afghanistan

Teenagers have a high prevalence of ascariasis in low-income countries with endemic disease, and their hygienic behaviors and access to proper sanitation may be limited in rapidly urbanizing settings. We studied university students in Kabul to estimate the proportion with ascariasis and determine the prevalence of risk factors for infection. Ascariasis was assessed through microscopy for 520 students attending Kabul Medical University. Overall, 15.8% of students were infected. Living in a hostel (21.2% versus 10.4% in houses) using well water (27.7% versus 9.7% for piped water), eating street food (29.4% versus 3.0% for those who do not), and eating unwashed vegetables (63.6% versus 8.8% for those who do not) were risk factors for infection. Recent city migrants who live in group hostels, including students, are important targets for interventions to reduce ascariasis. Such interventions could include encouraging individuals to prepare their own food and use only potable water.

Predictors and Barriers to Full Vaccination among Children in Ethiopia

Predictors of immunization status outside of large cities in Ethiopia are not well known, and Muslims have lower vaccination coverage. The aim of this study is to assess factors associated with full immunization among children 12–23 months in Worabe, Ethiopia, a Muslim-majority community. A cross-sectional study is conducted in summer 2016. Multivariable logistic regression was used to assess the significance of predictors of full immunization. Among 484 children, 61% are fully vaccinated. Children whose mothers had fewer antenatal care (ANC) visits have decreased odds of full vaccination (zero visits: odds ratio (OR) = 0.09; one visit: OR = 0.15; two visits: OR = 0.46; three visits: OR = 0.89). The most common reasons that the mother gave for not vaccinating the child are fear of side reactions (36%), being too busy (31%), or hearing rumors about vaccines (28%). Local interventions incorporating interventions with religious authorities could raise awareness in the community of the importance of childhood immunizations and ANC visits.

Vaccination timeliness and co-administration among Kenyan children

BACKGROUND Timely administration of recommended vaccines requires children to have multiple vaccines co-administered in the first year of life. The objectives of this study were to estimate the proportion of timely vaccinations and the proportion of co-administered vaccines, and to assess the relationship between vaccine co-administration and vaccine timeliness in Kenyan children. METHODS Using the 2014 Kenyan Demographic and Health Survey (DHS), we calculated the proportion of children who received co-administered and timely vaccine doses. Co-administration was defined as doses administered on the same day with dates recorded on vaccination cards. Vaccines were considered timely if given within four days before to four weeks after the recommended interval for administration. RESULTS 10,385 children aged 1-4 years in the Kenyan 2014 DHS dataset had vaccination cards which comprised the study sample. Analysis revealed wide a range for receipt of timely doses, from 90.2% for OPV0 to 56.0% for Measles. Co-administration of the 6-week dose was associated with 2.81 times higher odds of a timely Penta dose 1 (95% CI: 2.28, 3.46) and birth-dose co-administration was associated with a substantial increase in timely BCG vaccination: AOR 7.43 (95% CI: 6.31, 8.75). CONCLUSIONS Though vaccine coverage in Kenya was high, timely vaccination was markedly low, with resultant implications for population immunity and potential spread of communicable diseases in unvaccinated infants. Co-administration of vaccines, place of residence, wealth index, and child age were consistently related to the odds of timely vaccine receipt. These relationships reinforce the importance of dedicating resources to programs that educate low socio-economic groups about the importance of vaccine co-administration.

Childhood full and under-vaccination in Nigeria, 2013

BACKGROUND Nigerias government is challenged with vaccinating the worlds third largest birth cohort within a culturally and socioeconomically diverse country. This study estimated full childhood immunization coverage in Nigeria and characterizes the association between vaccination status and urbanicity, region of residence, ethnicity, and other factors. METHODS In 2013, households throughout Nigeria were enrolled in the Demographic and Health Survey which included questions about vaccination. We defined full vaccination of a child as having received a single dose of bacillus Calmete-Guerin (BCG), one dose of measles-containing vaccine (MCV), three doses of diphtheria, pertussis, tetanus (DPT), and four doses of oral polio vaccine (OPV). Using a multinomial logistic regression model, full vaccination and under-vaccination versus non-vaccination was regressed onto various demographic and socioeconomic characteristics. RESULTS Among 5759 children 1 year of age, 25.5% were fully vaccinated, 47.9% were under-vaccinated, and 26.6% had not received any vaccinations. Children were more likely to be fully vaccinated if they belonged to wealthier families, resided in southern regions of the country, were Christian, belonged to the Igbo or Yoruba ethnic group, had mothers who made ≥5 antenatal care visits, delivered at an institution, or were more highly educated. CONCLUSIONS Full vaccination among children in Nigeria is exceptionally low by global standards and certain groups, such as Muslims and individuals in northern regions who are higher risk of non- or under-vaccination should be targeted by vaccination programs. Providing a wide range of health care services for mothers and pregnant women could improve full vaccination of children.

Vaccination status of children aged 1–4 years in Afghanistan and associated factors, 2015

BACKGROUND Childhood mortality in Afghanistan fell by half between 1990 and 2015, due in part to the governments commitment to improving pediatric immunization services. Although progress has been made, immunization coverage has nonetheless remained low with only 65% of children receiving the third dose of Diphtheria-Pertussis-Tetanus (DPT3) based on WHO estimates. This study aims to calculate the proportion of Afghan children aged 1-4 years who were fully vaccinated, under-vaccinated, or non-vaccinated with government-recommended Expanded Program on Immunization vaccines and identify predictors related to the familys sociodemographic status and maternal autonomy. METHODS Data from the 2015 Afghanistan Demographic and Health Survey was used to calculate the proportion of children who were fully vaccinated (i.e. received all recommended vaccines), under-vaccinated (i.e. received some, but not all), and non-vaccinated (i.e. did not receive any vaccines) according to WHO guidelines. A multivariable multinomial logistic regression model generated odds ratios for under-vaccination and non-vaccination versus full vaccination, and examined associations between independent factors and full vaccination status. RESULTS We found 40.6% of Afghan children age 1-4 were fully vaccinated, 42.4% under-vaccinated, and 17% non-vaccinated. Large disparities characterized immunization coverage among provinces and between urban and rural regions. Birthing in a government institution (vs. non-institutional setting), a higher number of antenatal care visits, and a visit to a health facility in the past 12 months were all associated with increased odds of full immunization. Factors related to maternal autonomy including maternal decision-making and maternal attitudes towards beating were also significantly associated with vaccination status. CONCLUSION Approximately 60% of children in Afghanistan are under-vaccinated or non-vaccinated, leaving millions of children unnecessarily at risk for vaccine-preventable diseases. Engagement with community and religious leaders to create programs that increase womens autonomy and expand access to institutional delivery could lead to downstream increases in childhood vaccination coverage.

Socioeconomic factors associated with full childhood vaccination in Bangladesh, 2014

OBJECTIVES Childhood vaccination in Bangladesh has improved, but there is room for improvement. This study estimated full immunization coverage in Bangladeshi children and characterized risk factors for incomplete immunization. METHODS Using the 2014 Bangladesh Demographic and Health Survey (DHS), full vaccination of children aged 12 to 24 months was examined; this was defined as the receipt of one dose of bacillus Calmette-Guérin (BCG), three doses of pentavalent vaccine, three doses of oral polio vaccine (OPV), and one dose of measles-containing vaccine (MCV). Associations between full vaccination and selected risk factors were assessed by logistic regression. RESULTS Overall, 83% of children were fully vaccinated. BCG had the highest completion (97%), followed by OPV (92%), pentavalent vaccine (91%), and MCV (85%). Full vaccination coverage ranged from 64.4% in Sylhet to 90.0% in Rangpur and was lowest among non-locals of all regions (78.4%). Children who were in the lowest wealth quintile, who had mothers without antenatal care visits, or who had mothers without autonomy in healthcare decision-making were less likely to be fully vaccinated. CONCLUSIONS Overall, full vaccination of children is high, but varies by vaccine type. Disparities still exist by wealth and by region. Maternal access to care and autonomy in healthcare decision-making are associated with higher vaccination coverage.