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Background Immunization is one of the most effective measures for preventing disease when vaccination coverage is sufficient. Although vaccination coverage is known to be influenced by social and cultural barriers, the determinants of childhood immunization in Myanmar remain poorly understood. This study analyzed factors that influenced complete vaccination status (one dose each for Bacillus Calmette-Guérin and measles and three doses each for diphtheria-pertussis and polio) using 2015 data from the Myanmar Demographic Health and Survey. Methods Data from 12 to 23-month-old children and their mothers were extracted from the nationally representative survey results. Bivariate and multivariate analyses with survey-weighted logistic regression were performed to examine the relationships between vaccination status and various sociodemographic and medical factors. The independent variables for the analyses included area of residence, economic status, maternal age, marital status, education, literacy, employment status, antenatal care attendance, tetanus vaccination, place of delivery, postnatal evaluations, child’s sex, number of children, previous child death, decision maker(s) regarding child’s health, frequency of healthcare visits, paternal education, and paternal occupation. Results A representative sample of 904 cases were extracted for the analysis. The overall complete vaccination rate was 55.4%. In the multivariate analysis with backward step-wise selection, complete vaccination was independently associated with middle or high economic status (adjusted odds ratio [AOR]: 2.64, 95% confidence interval [CI]: 1.85–3.78), older maternal age (AOR: 2.87, 95% CI: 1.62–5.10), ≥4 antenatal care visits (AOR: 1.87, 95% CI: 1.28–2.73), and maternal tetanus vaccination before delivery (AOR: 3.26, 95% CI: 1.82–5.85). Conclusion The first Demographic and Health Survey in Myanmar revealed that only approximately one-half of 12–23-year-old children had received complete vaccination, which was lower than the estimated rate from routine administrative coverage. Our results indicate that incomplete immunization status was associated with low economic status, younger maternal age, fewer antenatal care visits, and no maternal tetanus vaccination. These findings may help improve the targeting and strategic implementation of the Expanded Programme on Immunization.

Vaccines are one of the most important achievements in public health, and a major contributor to this success is the Expanded Programme on Immunization. The utilisation of vaccination services and completion of the recommended schedule are determined by numerous factors. In Lao People’s Democratic Republic (Lao PDR), the overall immunisation coverage has been improving. However, notwithstanding the improvement in immunisation coverage and the supplementary immunisation activities, there have been measles, diphtheria, and polio outbreaks in the country. The recent multicounty study of household health surveys revealed that the within-country economic-related inequality in the delivery of a vaccine was still high in Lao PDR.Our previous work evaluated the factors associated with vaccination status among the children aged 5–9 years old, which was older age group for this type of study. This study evaluated factors that affect vaccination status among children aged between 12 and 35 months. It is a nationwide population-based cross-sectional study that used data obtained through multistage cluster sampling. We found that the proportion of infants who were fully immunised was lower than the national target and that “maternal ethnicity” (odds ratio (OR) 0.34, 95% confidence interval [CI]: 0.20–0.60), “paternal education” (OR 1.87, 95% CI: 1.12–3.10), and “source of information about vaccination date by medical staff” (OR 1.65, 95% CI: 1.01–2.71) were significantly associated with the children’s vaccination status. Numerous factors are associated with the completion of the recommended vaccine schedule, and some factors are location-specific. Identification of these factors should lead to actions for facilitating the optimal use of vaccination services by all the children in Lao PDR.

BackgroundMeasles outbreaks have occurred in some countries despite supplementary immunization activities (SIA) using measles-containing vaccine with high vaccination coverage. We conducted a cross-sectional seroprevalence survey to estimate population immunity in Lao People's Democratic Republic where repeated mass immunization has failed to eliminate measles.Methods and findingsIn this nationwide multistage cluster sampling survey conducted in 2014 based on probability proportionate to size sampling, blood samples were collected from 2,135 children and adults living in 52 randomly selected villages. Anti-measles and anti-rubella IgG were measured, and IgG prevalence was calculated. We applied mathematical modelling to estimate the number of cases of congenital rubella syndrome (CRS) in 2013 that were averted by the 2011 SIA. A stability testing was applied to the MR vaccine at 4°C, 25°C, and 35°C to examine stability differences between measles and rubella vaccine components. Measles IgG prevalence was significantly lower in the target age groups (5–21 years) of the 2011 SIA using a combination vaccine for measles and rubella vaccine (MR vaccine) than in young adults (22–39 years) (86.8% [95% CI: 83.0–90.6] vs. 99.0% [98.3–99.8]; p<0.001), whereas rubella IgG prevalence was significantly higher (88.2% [84.5–91.8] vs. 74.6% [70.7–78.5]; p<0.001). In the SIA target age groups, prevalence of measles IgG, but not rubella IgG, increased with age. CRS cases prevented in 2013 ranged from 16 [0–50] to 92 [32–180] if the force of infection had remained unchanged or had been reduced by 75%, respectively. In freeze-dried conditions, the measles vaccine component was more heat sensitive than the rubella component.ConclusionsInconsistent IgG prevalence between measles and rubella in Lao PDR can be partly explained by different stability of the measles and rubella vaccine components under heat exposure. Suboptimal vaccine handling may cause insufficient immunogenicity for measles, which subsequently leads to an outbreak despite high SIA coverage, while direct evidence is lacking. Temperature monitoring of the vaccine should be conducted.

Human standard astroviruses, serotypes 1 to 7, and 35 Japanese isolates were typed by reverse transcription and polymerase chain reaction (RT-PCR) with serotype-specific primers for the first time. The results were identical with those obtained by enzyme immunoassay with serotype-specific polyclonal antibodies, a method which has already been reported. RT-PCR with serotype-specific primers is useful for epidemiological studies of astroviruses where serotype-specific polyclonal antibodies are not available. Two parts of the capsid region, N terminus and C terminus, were sequenced. Serotypes differed in those regions. The N terminus differed less than the C terminus between serotypes. Both the N terminus and C terminus were similar intraserotypically with the exception of serotype-4 isolates which could be divided into A and B subgroups on the basis of their C terminus sequences, which were not known previously. Human astroviruses are non-enveloped, single-stranded RNA viruses which were first identified in 1975 by the electron microscopy of stool specimens from children with diarrhea (1, 8). Not only sporadic cases but also outbreaks of astroviruses have been reported (9,13,19). Astroviruses can be cultured in LLC-MK2 cells and CaCo-2 cells (5,22). From the cultured viruses, seven human astrovirus serotypes have been identified serologically by using serotype-specific polyclonal antibodies (6). Serotype 8 was recently reported in a database (Accession No. Z66541).The complete genomic sequences of human astrovirus 1 were determined in 1994 (7, 23). After that, the total capsid sequences of serotypes 2, 4 and 6 were reported (3, 6, 11,24). The partial sequence of the capsid region of serotype 3 is also known (12). These results enabled us to detect and sequence astroviruses by reverse transcription and polymerase chain reaction (RT-PCR) (16).We obtained and cultured the standard astroviruses, serotypes 1 to 7. We then analyzed the full length of the capsid regions by RT-PCR and sequencing (preparing for submission). From these results, we designed serotypespecific oligonucleotide primers in the capsid region. We then compared the serotypes as determined by RT-PCR and enzyme immunoassay (EIA) using serotypespecific polyclonal antibodies on Japanese strains of astroviruses. Moreover, we compared the nucleotides and the predicted amino acid sequence homologies in two parts of the capsid region.Our main purpose was to verify that RT-PCR with serotype-specific primers is applicable to the epidemiological study of astrovirus serotypes as compared to serotyping by EIA and sequence analysis because serotype-specific antibodies are commercially unavailable and there are limited epidemiological studies. In addition, the sequence of the capsid region is analyzed in two parts of the relatively conservative portion, N terminus, and relatively variable portion, C terminus, to deter-