Anonh Xeuatvongsa

Influenza Vaccination Guidelines and Vaccine Sales in Southeast Asia: 2008-2011

Background Southeast Asia is a region with great potential for the emergence of a pandemic influenza virus. Global efforts to improve influenza surveillance in this region have documented the burden and seasonality of influenza viruses and have informed influenza prevention strategies, but little information exists about influenza vaccination guidelines and vaccine sales. Methods To ascertain the existence of influenza vaccine guidelines and define the scope of vaccine sales, we sent a standard three-page questionnaire to the ten member nations of the Association of Southeast Asian Nations. We also surveyed three multinational manufacturers who supply influenza vaccines in the region. Results Vaccine sales in the private sector were <1000 per 100,000 population in the 10 countries. Five countries reported purchasing vaccine for use in the public sector. In 2011, Thailand had the highest combined reported rate of vaccine sales (10,333 per 100,000). In the 10 countries combined, the rate of private sector sales during 2010–2011 (after the A(H1N1)2009pdm pandemic) exceeded 2008 pre-pandemic levels. Five countries (Indonesia, Malaysia, Singapore, Thailand and Vietnam) had guidelines for influenza vaccination but only two were consistent with global guidelines. Four recommended vaccination for health care workers, four for elderly persons, three for young children, three for persons with underlying disease, and two for pregnant women. Conclusions The rate of vaccine sales in Southeast Asia remains low, but there was a positive impact in sales after the A(H1N1)2009pdm pandemic. Low adherence to global vaccine guidelines suggests that more work is needed in the policy arena.

The Effect of Influenza Vaccination on Birth Outcomes in a Cohort of Pregnant Women in Lao PDR, 2014–2015

BACKGROUND Some studies suggest that maternal influenza vaccination can improve birth outcomes. However, there are limited data from tropical settings, particularly Southeast Asia. We conducted an observational study in Laos to assess the effect of influenza vaccination in pregnant women on birth outcomes. METHODS We consented and enrolled a cohort of pregnant woman who delivered babies at 3 hospitals during April 2014-February 2015. We collected demographic and clinical information on mother and child. Influenza vaccination status was ascertained by vaccine card. Primary outcomes were the proportion of live births born small for gestational age (SGA) or preterm and mean birth weight. Multivariate models controlled for differences between vaccinated and unvaccinated women and influenza virus circulation. RESULTS We enrolled 5103 women (2172 [43%] were vaccinated). Among the 4854 who had a live birth, vaccinated women were statistically significantly less likely than unvaccinated women to have an infant born preterm during the period of high influenza virus circulation (risk ratio [RR] = 0.56, 95% confidence interval [CI], .45-.70), and the effect remained after adjusting for covariates (adjusted RR, 0.69; 95% CI, .55-.87). There was no effect of vaccine on mean birth weight. Vaccinated mothers had a statistically significant elevated risk of having an infant born SGA (adjusted RR, 1.25; 95% CI, 1.11–1.41). CONCLUSIONS In this observational study, we found indirect evidence of influenza vaccine safety during pregnancy, and women who received vaccine had a reduced risk of delivering a preterm infant during times of high influenza virus circulation. Vaccination may prevent 1 in 5 preterm births that occur during periods of high influenza circulation.

Chronic Hepatitis B Prevalence among Children and Mothers: Results from a Nationwide, Population-Based Survey in Lao People's Democratic Republic

Background Hepatitis B is regarded as a serious public health issue in Lao Peoples Democratic Republic (Lao PDR), a Southeast Asian country. However, disease epidemiology among the general population is not well known, and thus a nationwide cross-sectional survey for hepatitis B surface antigen (HBsAg) prevalence in children and their mothers was conducted. Methods and findings We applied three-stage cluster sampling using probability proportionate to size. After randomly selecting child (5 to 9 years old) and mother (15 to 45 years old) pairs from the selected villages, questionnaires and HBsAg rapid tests were conducted. Data from 965 child and mother pairs were analyzed. Multivariate logistic regression analyses were used to investigate the independent association of individual background characteristics for the odds of being HBsAg positive. In total, 17 children and 27 mothers were HBsAg positive. HBsAg prevalence was estimated to be 1.7% (95% confidence interval: 0.8%-2.6%) in children, and 2.9% (95% confidence interval: 1.7%–4.2%) in their mothers after taking sampling design and weight of each sample into account. Mothers infection status was positively associated with HBsAg positivity in children (p<0.001), whereas other potential risk factors, such as ethnicity, proximity to health centers, and history of surgery, were not. There were no significant associations between mothers HBsAg status and history of surgery, and other sociodemographic factors. Conclusions Despite the slow implementation of the hepatitis B vaccination program, HBsAg prevalence among children and their mothers was not high in Lao PDR compared to reports from neighboring countries. The reasons for the differences in prevalence among these countries are unclear. We recommend that prevalence surveys be conducted in populations born before and after the implementation of a hepatitis B vaccination program to better understand the epidemiology of hepatitis B.

Integration of deworming into an existing immunisation and vitamin A supplementation campaign is a highly effective approach to maximise health benefits with minimal cost in Lao PDR

Infection with soil-transmitted helminths (STH) is a major public health problem in many developing countries, with pregnant women and children particularly at risk. Preventive chemotherapy, which is the intervention currently recommended by the WHO against the main helminth infections including those caused by STHs, aims at reducing morbidity through periodical administration of anthelminthic drugs either alone or in combination. The Expanded Programme on Immunization is one of the most widely implemented health programmes in the world and has well established access to children and women. The present study investigated the cost of the provision of anthelminthic drugs during existing immunisation campaigns. In Lao PDR, use of this integrated approach compared with implementation of the vertical deworming campaign alone allowed a reduction of the individual cost of deworming by 10 times (from US

Introducing seasonal influenza vaccine in low-income countries: an adverse events following immunization survey in the Lao People's Democratic Republic.

0.23 in the vertical deworming campaign to US

Determination of factors affecting the vaccination status of children aged 12–35 months in Lao People’s Democratic Republic

0.03 in the integrated campaign). When drug cost was excluded, the cost of deworming an individual was US

Seroprevalence of chronic hepatitis B, as determined from dried blood spots, among children and their mothers in central Lao People's Democratic Republic: a multistage, stratified cluster sampling survey.

0.007, implying that deworming 100 children would cost less than US

The Lao Experience in Deploying Influenza A(H1N1)pdm09 Vaccine: Lessons Made Relevant in Preparing for Present Day Pandemic Threats.

1 if drug donation was in place. The burden posed on health workers by the integration process was perceived as minimal and manageable. Moreover, delivery of anthelminthic drugs during immunisation campaigns enabled campaign teams to observe drug intake directly, which assured safety. These findings prove that integration is an opportunity to maximise health benefits through the delivery of multiple health products and the attainment of high coverage.

Immunity levels to poliovirus in Lao children and adults before the vaccine-derived poliovirus outbreak: A retrospective study

In 2012, Lao PDR introduced seasonal influenza vaccine in pregnant women, persons aged ≥50 years, persons with chronic diseases, and healthcare personnel. We assessed adverse events following immunization (AEFI).

Evaluation of nationwide supplementary immunization in Lao People's Democratic Republic: Population-based seroprevalence survey of anti-measles and anti-rubella IgG in children and adults, mathematical modelling and a stability testing of the vaccine.

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.