Age-specific prevalence of IgG against measles/rubella and the impact of routine and supplementary immunization activities: A multistage random cluster sampling study with mathematical modelling.

BACKGROUND: Vietnam continues to have measles and rubella outbreaks following supplementary immunization activities (SIA) and routine immunization despite both having high reported coverage. To evaluate immunization activities, age-specific immunity against measles and rubella, and the number of averted Congenital Rubella Syndrome (CRS) cases, must be estimated. METHODS: Dried blood spots were collected from 2091 randomly selected individuals aged 1-39 years. Measles and rubella virus-specific immunoglobulin G (IgG) were measured by enzyme immunoassay. Results were considered positive at ≥120 mIU/mL for measles and ≥10 IU/mL for rubella. The number of CRS cases averted by immunization since 2014 were estimated using mathematical modelling. RESULTS: Overall IgG seroprevalence was 99.7% (95%CI: 99.2-99.9) for measles and 83.6% (95%CI: 79.3-87.1) for rubella. Rubella IgG seroprevalence was higher among age groups targeted in the SIA than in non-targeted young adults (95.4% [95%CI: 92.9-97.0] vs 72.4% [95%CI: 63.1-80.1]; P < 0.001). The estimated number of CRS cases averted in 2019 by immunization activities since 2014 ranged from 126 (95%CI: 0-460) to 883 (95%CI: 0-2271) depending on the assumed postvaccination reduction in the force of infection. CONCLUSIONS: The results suggest the SIA was effective, while young adults born before 1998 who remain unprotected for rubella require further vaccination.

Estimates of the global burden of Congenital Rubella Syndrome, 1996-2019.

OBJECTIVES: Many countries introduced rubella-containing vaccination (RCV) after 2011, following changes in recommended World Health Organization (WHO) vaccination strategies and external support. We evaluated the impact of these introductions. METHODS: We estimated the country-specific, region-specific, and global Congenital Rubella Syndrome (CRS) incidence during 1996-2019 using mathematical modeling, including routine and campaign vaccination coverage and seroprevalence data. RESULTS: In 2019, WHO African and Eastern Mediterranean regions had the highest estimated CRS incidence (64 [95% confidence intervals (CI): 24-123] and 27 [95% CI: 4-67] per 100,000 live births respectively), where nearly half of births occur in countries that have introduced RCV. Other regions, where >95% of births occurred in countries that had introduced RCV, had a low estimated CRS incidence (<1 [95% CI: <1 to 8] and <1 [95% CI: <1 to 12] per 100,000 live births in South-East Asia [SEAR] and the Western Pacific [WPR] respectively, and similarly in Europe and the Americas). The estimated number of CRS births globally declined by approximately two-thirds during 2010-2019, from 100,000 (95% CI: 54,000-166,000) to 32,000 (95% CI: 13,000-60,000), representing a 73% reduction since 1996, largely following RCV introductions in WPR and SEAR, where the greatest reductions occurred. CONCLUSIONS: Further reductions can occur by introducing RCV in remaining countries and maintaining high RCV coverage.

Comparison of population-based measles-rubella immunoglobulin G antibody prevalence between 2014 and 2019 in Lao People's Democratic Republic: Impacts of the national immunization program.

OBJECTIVES: We evaluated the effectiveness of the Lao People's Democratic Republic's measles-rubella immunization program using the seroprevalence from two cross-sectional surveys. METHODS: The nationwide surveys occurred in 2014 and 2019 using a multistage cluster sampling, both requiring samples from 2184 individuals from 52 randomly selected villages. Immunoglobulin G titers, measured using enzyme-linked immunosorbent assay, were considered positive at ≥120 mIU/ml (measles) and ≥10 IU/ml (rubella). We calculated the vaccination-related reduction in the force of rubella infection and the number of congenital rubella syndrome cases averted in 2019. RESULTS: We collected 2135 (women: 55.2%, mean age: 23.2 years) and 2001 (52.7%, 23.1 years) samples in 2014 and 2019, respectively. During 2014-2019, immunoglobulin G prevalence increased from 83.9% (95% confidence interval [CI]: 83.8-84.0) to 98.3% (97.7-98.8) for measles and from 75.4% (75.3-75.5) to 87.8% (86.4-89.2) for rubella. The most plausible reduction in the average force of rubella infection was 100% (95% CI: 28-100) since vaccination started, averting 78 (95% CI: 42-128) congenital rubella syndrome cases in 2019. CONCLUSION: This is the first population-based study for measles and rubella at two different time points in developing countries. Measles and rubella seroprevalence increased significantly during 2014-2019, greatly exceeding the immunity thresholds for their elimination.

The determinants of immunization coverage among children aged between 12 and 35 months: a nationwide cross-sectional study in Lao People's Democratic Republic.

BACKGROUND: Immunization is one of the most important public health interventions for reducing morbidity and mortality in children. However, factors contributing to low immunization coverage are not fully understood in the Lao People's Democratic Republic (Lao PDR). Therefore, this study aimed to identify factors associated with full immunization coverage among children between 12 and 35 months, providing up-to-date information for immunization programs in Lao PDR. METHODS: We analyzed the subpopulation of a nationwide cross-sectional survey using a multistage cluster sampling procedure to evaluate the measles and rubella seroepidemiology. In addition, we categorized children aged between 12 and 35 months into two groups: "fully immunized" children with a birth dose of Bacillus Calmette and Guérin vaccine, hepatitis B vaccine (Hep B), one and three doses for the measles-containing vaccine (MCV) and pentavalent vaccine and pneumococcal conjugate vaccine (PCV) and "partially immunized" children who missed any dose of vaccine. Immunization coverage was calculated as the ratio of "fully immunized" to the total. We compared the groups' demographic characteristics and health service utilization as independent variables. Multivariate logistic regression was used to assess the relationship between immunization coverage, various demographic factors, and health service utilization. RESULTS: Overall, 256 of the 416 targeted pairs were included in the analysis. In total, 67.6% of the children were fully immunized. Childbirth at hospitals or health facilities (adjusted odds ratio: 9.75, 95% confidence interval: 5.72-16.62, p < 0.001) was the predictor of full immunization coverage. The 83 children in the partially immunized groups were attributed to Hep B at birth (46, 55.4%), three doses of PCV (34, 41.0%), and the first dose of the MCV (27, 32.5%). CONCLUSION: Our study elucidated that the immunization status among children aged between 12 and 35 months in Lao PDR is satisfactory in improving access to healthcare by strengthening communication with residents regarding health service utilization, and expanding mobile outreach services may play a pivotal role in this endeavor. Further research is warranted to evaluate efforts to increase immunization coverage and target populations with limited access to healthcare.

Impact of hepatitis B vaccination programs in Vietnam evaluated by estimating HBsAg prevalence.

Background: Vietnam introduced a 3-dose hepatitis B (HBV) immunization program comprising 1 dose immediately after birth and 2 or 3 in infancy in the past 20 years, but the impact of the vaccine has not been systematically evaluated. Thus, we conducted this survey aiming to estimate the age-specific chronic HBV prevalence in the general population and to evaluate HBV immunization effectiveness. Methods: Population-based, four-stage cluster sampling was used in the South Central Coast region of Vietnam. The point-of-care Determine rapid test was used to assess hepatitis B surface antigen (HBsAg) positivity. Results: A total of 2,075 samples were included in the study. HBsAg prevalence was significantly higher among adults aged 20-39 years than in the population aged 1-19 years (8.0% [95% confidence interval 5.0-12.0] vs. 2.0% [95% confidence interval 1.0-6.0], p<0.01). HBsAg prevalence decreased after implementation of the 3-dose vaccination schedule during infancy from 1997 to 2002, whereas the change in prevalence after implementation of the birth dosing was not significant. A slight increase in HBsAg prevalence was observed for the cohort born in 2011, 2012, and 2013, when there was a vaccine shortage and media reports of immunization resistance. Conclusions: This is the first population-based assessment of the introduction of the HBV vaccine in Vietnam performed by estimating the HBsAg prevalence across a wide range of ages. The results showed that the HBV immunization policy effectively reduces HBsAg prevalence in general, although birth dosing of the vaccine and low immunization coverage should be carefully monitored.

Prevalence of hepatitis B and C virus infections in Lao People's Democratic Republic: The first national population-based cross-sectional survey.

Population-based seroprevalence of chronic hepatitis B and C infections has not been examined in Lao People's Democratic Republic (PDR). Therefore, this study aimed to estimate the seroprevalence of these infections in the general population of Lao PDR and perform subgroup analysis. A nationwide seroprevalence survey was conducted in Lao PDR in June 2019 using the multistage cluster sampling method. Dried blood spot samples were collected onto WhatmanTM 903 filter paper by finger prick. A chemiluminescent microparticle immunoassay was used to measure the levels of hepatitis B surface antigen (HBsAg) and hepatitis C antibody (HCV-Ab). Samples in which the HBsAg level was above 0.05 IU/ml and HCV-Ab was above the signal/cutoff ratio of 1.0 were considered positive based on comparisons with the relative light unit value of a calibration sample. A total of 1,927 samples (male: 47.3%, mean age: 23.0 years) were included in the analysis. The prevalence was estimated to be 4.2% (95% confidence interval [CI]: 2.7-6.3) for HBsAg and 1.6% (95% CI: 0.5-5.3) for HCV-Ab. Multivariable analysis revealed that those aged 20-24 years (adjusted odds ratio (AOR): 2.3, 95% CI: 1.1-4.6), those aged 25-29 years (AOR: 2.7, 95% CI: 1.3-5.6), those from the Northern region (AOR: 2.8, 95% CI: 1.2-6.6), and those who were Khmu (AOR: 3.6, 95% CI: 2.0-6.8) or Hmong (AOR: 5.0, 95% CI: 3.3-7.5) were significantly more likely to be positive for HBsAg. Although there were no statistically significant differences in the HCV-Ab prevalence according to each variable, males (2.9%, 95% CI: 0.7-10.7), those aged ≥40 years (6.1%, 95% CI: 2.1-16.8), and those from the Southern region (3.3%, 95% CI: 0.6-15.3) tended to have a higher prevalence. This novel population-based survey found differences in the prevalence of chronic hepatitis B and hepatitis C virus infections in Lao PDR according to sex, age group, region, and ethnicity; however, the results of this study should be confirmed in future studies, and relevant responses tailored for each target also need to be determined to control the transmission of hepatitis B and C infections.

Comparison between a rapid diagnostic test and dried blood spot-based immunoassay for hepatitis B surface antigen testing: Performance and cost implications in a population-based serosurvey in Vietnam.

OBJECTIVES: This study aimed to determine the agreement between a rapid diagnostic test (RDT) and a dried blood spot (DBS)-based electrochemiluminescence immunoassay (ECLIA) of hepatitis B surface antigen and to compare the costs of conducting serosurveys using RDTs and DBS in a field setting. METHODS: A serosurvey was conducted in the South Central Coast region of Vietnam in May 2019. Participants aged 1-39 years were recruited using a four-stage random sampling method and tested for hepatitis B surface antigen using an RDT kit (Alere Determine) and a DBS-based ECLIA. The agreement between the RDT and the DBS-based ECLIA was assessed using cross-tabulation and Cohen kappa. Cost data were categorized by input (personnel, transportation, field consumables, laboratory consumables, and capital item/overhead) and survey phase (survey preparation, data/biospecimen collection, laboratory testing, and coordination). RESULTS: A total of 2072 participants were analyzed. There was a 99% agreement between the RDT and the DBS-based ECLIA results, with a Cohen kappa of 0.9. The estimated cost of conducting a serosurvey by DBS was UD $75,291, whereas RDT was $53,182. CONCLUSION: RDTs and DBS-based ECLIA provide test results with high agreements. RDTs are a better option in terms of cost, whereas the DBS-based ECLIA may be useful when evaluating multiple infectious diseases.

Public knowledge, practices, and awareness of antibiotics and antibiotic resistance in Myanmar: The first national mobile phone panel survey.

In 2017, the Myanmar National Action Plan for Containment of Antimicrobial Resistance (AMR) (2017-2022) was endorsed by the Ministry of Health and Sports, Myanmar; one of its objectives was to increase public awareness of AMR to accelerate appropriate antibiotic use. This survey aimed to assess the public knowledge, practices and awareness concerning antibiotics and AMR awareness among adults in Myanmar. We conducted a nationwide cross-sectional mobile phone panel survey in January and February 2020. Participants were randomly selected from the mobile phone panel in each of three groups stratified by gender, age group, and residential area urbanity; they were interviewed using a structured questionnaire. Collected data were weighted based on the population of each stratum from the latest national census and analyzed using descriptive and inferential statistics. Two thousand and forty-five adults from 12 regions and states participated in this survey. Overall, 89.5% of participants had heard about antibiotics; however, only 0.9% provided correct answers to all five questions about antibiotics, whereas 9.7% provided all incorrect answers. More than half of participants (58.5%) purchased antibiotics without a prescription, mainly from medical stores or pharmacies (87.9%); this was more frequent in age group (18-29 years) and those in rural areas (p = 0.004 and p < 0.001, respectively). Only 56.3% were aware of antibiotic resistance and received their information from medical professionals (46.3%), family members or friends (38.9%), or the media (26.1%). Less than half (42.4%) knew that antibiotics were used in farm animals. Most did not know that using antibiotics in farm animals could develop resistance (73.2%) and is banned for the purposes of growth stimulation (64.1%). This survey identifies considerable gaps in the knowledge, practices, and awareness about antibiotics among the general population in Myanmar. Continuous public education and awareness campaigns must be urgently conducted to fulfill these gaps, which would aid in promoting antibiotic stewardship, leading to combating AMR in Myanmar.

Effectiveness of immunization activities on measles and rubella immunity among individuals in East Sepik, Papua New Guinea: A cross-sectional study.

Objectives: This study aimed to assess measles and rubella immunity by measuring virus-specific immunoglobulin G (IgG) prevalence among individuals and evaluate the effectiveness of recent supplementary immunization activities (SIAs) by comparing the antibody positivity rates of the SIA target age groups in 2015 with those in 2019 as measles and rubella are endemic in Papua New Guinea. Methods: A cross-sectional study. The measles- and rubella-specific IgG levels of patients aged ≥1 year at two clinics in East Sepik province, Papua New Guinea were assessed with commercially available virus-specific IgG EIA kits. Results: In total, 297 people participated in the study and 278 samples with sufficient volume, relevant information, and age inclusion criteria were analyzed. The overall IgG prevalence rates were 62.6% for measles and 82.0% for rubella. The age groups targeted in the 2019 SIAs had a higher IgG prevalence than those targeted in the 2015 SIAs for both the infectious diseases. Moreover, the IgG prevalence for rubella was higher than measles in these groups. Conclusions: The anti-measles and anti-rubella IgG prevalence in the target groups were lower than those required for herd immunity. The immunization program should be emphasized to eliminate measles and rubella. Further population-based studies are warranted.

Vaccine temperature management in Lao People's Democratic Republic: A nationwide cross-sectional study.

OBJECTIVE: The objective of the study was to evaluate the duration and frequency of vaccine exposure to suboptimal temperatures during transit from the central vaccine storage in the capital to health centers in Lao PDR. METHODS: Temperature data loggers traveled from the capital to the health centre storages (146) with the vaccines to monitor the vaccine temperature nationwide. One health centre per district was selected using a simple random sampling method for the first round of temperature monitoring. One health centre was selected from every forty-nine high risk districts monitor the trend of vaccine temperature at the health centre storage and during outreach sessions in several districts. Vaccines and temperature data loggers were transported using the normal vaccination transportation. FINDINGS: Overall, the vaccines were exposed to temperatures >8 °C for an average of 1648 min, equivalent to 9.0% of the observational period, and to temperatures <0 °C for an average of 184 min, equivalent to 1.35% of the study period. The proportion of exposure to temperatures >8 °C was the highest during the transit from the capital to the province. The proportion of exposure to temperatures <0 °C was the highest during storage at district level. Examined by region, vaccines in the northern provinces had higher risk of exposure to temperatures >8 °C; however, the risk of exposure to temperatures <0 °C was scattered nationwide. Moreover, some health centers showed fluctuations in storage temperature. CONCLUSIONS: Challenges associated with cold chain management, and the resulting deterioration of vaccines, might account for outbreaks of vaccine-preventable diseases. The government should examine and invest in suitable technologies and approaches to ensure consistency in cold chain management.

The necessity of continuous international cooperation for establishing the coronavirus disease 2019 diagnostic capacity despite the challenges of fighting the outbreak in home countries.

The importance of laboratory diagnostic capacity for effective infectious disease control has been widely recognized in recent years, but many of the countries still struggled to establish it when the newly discovered diseases was happened, such as coronavirus disease 2019 (COVID-19). Even in the country that the laboratory system was highly evaluated by Global Health Security Index like Myanmar, support from external partners is essential to establish the diagnostic capacity for COVID-19. WHO and other contributors, including Japan, have been supporting the establishment of a diagnostic system for SARS-CoV-2 in response to the disease outbreak. The testing laboratory was established in Myanmar on February 20, 2020. The first confirmed diagnosis was reported on March 23, and 15 positive cases as of March 31. Since it is difficult to control the outbreak in a given country without controlling it in the neighboring countries, continuous international cooperation for establishing the coronavirus disease 2019 diagnostic capacity was crucial despite the challenges of fighting the outbreak in home countries.

Estimating the immunogenicity of measles-rubella vaccination administered during a mass campaign in Lao People's Democratic Republic using multi-valent seroprevalence data.

Measles and rubella are important causes of morbidity and mortality globally. Despite high coverage reported for measles vaccination, outbreaks continue to occur in some countries. The reasons for these outbreaks are poorly understood. We apply Bayesian methods to multi-valent seroprevalence data for measles and rubella, collected 2 years and 3 months after a mass measles-rubella vaccination campaign in Lao PDR to estimate the immunogenicity and vaccination coverage. When the vaccination coverage was constrained to exceed 95% or 90%, consistent with officially-reported values, the immunogenicity of the measles vaccine component was unexpectedly low (75% (95% CR: 63-82%) and 79% (CR: 70-87%) respectively. The estimated immunogenicity increased after relaxing constraints on the vaccination coverage, with best-fitting values of 83% (95% CR: 73-91%) and 97% (95% CR: 90-100%) for the measles and rubella components respectively, with an estimated coverage of 83% (95% CR: 80-88%). The findings suggest that, if the vaccine coverage was as high as that reported, continuing measles outbreaks in Lao PDR, and potentially elsewhere, may be attributable to suboptimal immunogenicity attained in mass campaigns. Vaccine management in countries with high reported levels of coverage and ongoing measles outbreaks needs to be reviewed if measles elimination targets are to be achieved.

Seroprevalence of mumps before the introduction of mumps-containing vaccine in Lao PDR: results from a nationwide cross-sectional population-based survey.

OBJECTIVE: Mumps-containing vaccine is currently not a component of the national immunization schedule in Lao People's Democratic Republic (PDR). Mumps itself is not a notifiable disease in the country and the seroprevalence of anti-mumps immunoglobulin G (IgG) in the general population is unknown. In this study, anti-mumps IgG was measured in 2058 blood samples to evaluate population immunity in the country. RESULTS: The seroprevalence of anti-mumps IgG showed a gradual increase with increasing age, starting at 10.6% (95% CI 7.4-13.7) in participants aged 1-2 years, and almost plateaued at about 75% in individuals older than 11-12 years, though it still tended toward a small increase up to 89.6% (95% CI 86.6-92.6) in participants aged 40 years or older. Compared with the results of previous studies, this increase with increasing age is less marked and the plateau of anti-mumps seroprevalence is lower. We attribute this result mainly to the lower population density in Lao PDR.

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.

BACKGROUND: Measles 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 FINDINGS: In 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. CONCLUSIONS: Inconsistent 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.

Determination of factors affecting the vaccination status of children aged 12-35 months in Lao People's Democratic Republic.

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.

Cost-effectiveness analysis of the national decentralization policy of antiretroviral treatment programme in Zambia.

BACKGROUND: In resource-limited settings with a high prevalence of human immunodeficiency virus (HIV) infection such as Zambia, decentralization of HIV/acquired immunodeficiency syndrome (HIV/AIDS) treatment and care with effective use of resources is a cornerstone of universal treatment and care. OBJECTIVES: This research aims to analyse the cost effectiveness of the National Mobile Antiretroviral Therapy (ART) Services Programme in Zambia as a means of decentralizing ART services. METHODS: Cost-effectiveness analyses were performed using a decision analytic model and Markov model to compare the original ART programme, 'Hospital-based ART', with the intervention programme, Hospital-based plus 'Mobile ART', from the perspective of the district government health office in Zambia. The total cost of ART services, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) were examined. RESULTS: The mean annual per-patient costs were 1259.16 USD for the original programme and 2601.02 USD for the intervention programme, while the mean number of QALYs was 6.81 for the original and 7.27 for the intervention programme. The ICER of the intervention programme relative to the original programme was 2965.17 USD/QALY, which was much below the willingness-to-pay (WTP), or three times the GDP per capita (4224 USD), but still over the GDP per capita (1408 USD). In the sensitivity analysis, the ICER of the intervention programme did not substantially change. CONCLUSION: The National Mobile ART Services Programme in Zambia could be a cost-effective approach to decentralizing ART services into rural areas in Zambia. This programme could be expanded to more districts where it has not yet been introduced to improve access to ART services and the health of people living with HIV (PLHIV) in rural areas.

Longitudinal adherence to antiretroviral drugs for preventing mother-to-child transmission of HIV in Zambia.

BACKGROUND: Adherence to antiretroviral (ARV) drugs is essential for eliminating new pediatric infections of human immunodeficiency virus (HIV). Since the Zambian government revised the national guidelines based on option A (i.e., maternal zidovudine and infant ARV prophylaxis) of the World Health Organization's 2010 guidelines, no studies have assessed adherence to ARVs during pregnancy up to the postpartum period. This study aimed to examine adherence to ARVs and identify the associated risk factors. METHODS: A prospective cohort study was conducted in the Chongwe district from June 2011 to January 2014. Self-reported adherence to ARVs was examined during pregnancy and at one week, six weeks, and 24 weeks postpartum among 321 HIV-positive women. The probability of remaining adherent to ARVs was estimated using the Kaplan-Meier method, and the risk factors for non-adherence were identified using the Cox proportional hazard regressions--treating loss to follow-up as non-adherence. The statuses of HIV in HIV-exposed infants were assessed in January 2014. RESULTS: During the study period, 326 infants were born to HIV-positive women, 262 (80.4%) underwent HIV testing, and 11 (3.4%) had their HIV infection detected at the time that they had the latest HIV testing as of January 2014. The ARV adherence rate was 82.5% during pregnancy, 84.2% at one week postpartum, 81.5% at six weeks postpartum, and 70.5% at 24 weeks postpartum. The probability of remaining adherent to ARVs was 0.61 at day 50, 0.35 at day 100, 0.18 at day 200, and 0.06 at day 300. Attending a referral health center (HC) was a risk factor for non-adherence compared with attending rural HCs that provided HIV care/treatment (adjusted hazard ratio [aHR] 0.71, 95% confidence interval [CI] 0.57-0.88) and those that did not provide HIV care/treatment (aHR 0.58, 95% CI 0.46-0.74). A new diagnosis of HIV infection compared to a known HIV-positive status before pregnancy was another risk factor for non-adherence (aHR 1.24, 95% CI 1.03-1.50). CONCLUSIONS: Maintaining adherence to ARVs through pregnancy to the postpartum period remains a crucial challenge in Zambia. To maximize the treatment benefits, adherence to ARVs and retention in care should be improved at all health facilities.

Health outcomes and cost impact of the new WHO 2013 guidelines on prevention of mother-to-child transmission of HIV in Zambia.

BACKGROUND: Countries are currently progressing towards the elimination of new paediatric HIV infections by 2015. WHO published new consolidated guidelines in June 2013, which now recommend either 'Antiretroviral drugs (ARVs) for women living with HIV during pregnancy and breastfeeding (Option B)' or 'Lifelong antiretroviral therapy (ART) for all pregnant and breastfeeding women living with HIV (Option B+)', while de facto phasing out Option A. This study examined health outcomes and cost impact of the shift to WHO 2013 recommendations in Zambia. METHODS: A decision analytic model was developed based on the national health system perspective. Estimated risk and number of cases of HIV transmission to infants and to serodiscordant partners, and proportions of HIV-infected pregnant women with CD4 count of ≤350 cells/mm3 to initiate ART were compared between 2010 Option A and the 2013 recommendations. Total costs of prevention of mother-to-child transmission of HIV (PMTCT) services per annual cohort of pregnant women, incremental cost-effectiveness ratio (ICER) per infection averted and quality-adjusted life-year (QALY) gained were examined. RESULTS: Our analysis suggested that the shift from 2010 Option A to the 2013 guidelines would result in a 33% reduction of the risk of HIV transmission among exposed infants. The risk of transmission to serodiscordant partners for a period of 24 months would be reduced by 72% with 'ARVs during pregnancy and breastfeeding' and further reduced by 15% with 'Lifelong ART'. The probability of HIV-infected pregnant women to initiate ART would increase by 80%. It was also suggested that while the shift would generate higher PMTCT costs, it would be cost-saving in the long term as it spares future treatment costs by preventing infections in infants and partners. CONCLUSION: The shift to the WHO 2013 guidelines in Zambia would positively impact health of family and save future costs related to care and treatment.

Healthcare provision for HIV co-infected tuberculosis patients in rural Zambia: an observational cohort study at primary care centers.

BACKGROUND: Linkage of healthcare services for tuberculosis (TB) and human immunodeficiency virus (HIV) remains a major challenge in resource-limited settings. Our operational research aimed to evaluate the linkage between TB and HIV services in a rural area of Zambia, and to explore factors associated with the enrolment of TB/HIV co-infected patients in HIV care services. METHODS: All TB patients newly diagnosed as HIV-positive in Chongwe district, Zambia between 2009 and 2010 were included. Data from TB registers and medical records were reviewed. Patient referral to HIV services and provision of antiretroviral therapy (ART) were further examined through HIV registers and records. RESULTS: Of 621 patients (median age 33.0 years, female 42.4%) who started anti-TB treatment, clinic records indicated that 297 patients were newly diagnosed as HIV-positive, and 176 (59.3%) of these were referred to an ART clinic. Analysis of records at the ART clinic found that only 85 (28.6%) of TB/HIV patients had actually been enrolled in HIV care, of whom only 58 (68.2%) had commenced ART. Logistic regression analyses demonstrated the following factors associated with lower enrolment: "male" sex (aOR, 0.45; 95% CI 0.26-0.78), "previous TB treatment" (aOR, 0.29; 95% CI, 0.11-0.75), "registration at sites that did not provide ART services (non-ART site)" (aOR, 0.10; 95% CI, 0.01-0.77) and "death on TB treatment outcome (aOR, 0.20; 95% CI, 0.06-0.65). However, patient registration at TB clinics in 2010 was associated with markedly higher enrolment in HIV care as compared to registration in 2009 (aOR, 2.80; 95% CI, 1.53-5.12). CONCLUSIONS: HIV testing for TB patients has been successfully scaled up. However referrals of co-infected patients still remain a challenge due to poor linkage between TB and HIV healthcare services. Committed healthcare workers, a well-organized health services system and patient education are urgently required to ensure a higher rate of referral of TB/HIV co-infected patients for appropriate care.

Adherence to antiretroviral therapy (ART) during the early months of treatment in rural Zambia: influence of demographic characteristics and social surroundings of patients.

BACKGROUND: Around 70% of those living with HIV in need of treatment accessed antiretroviral therapy (ART) in Zambia by 2009. However, sustaining high levels of adherence to ART is a challenge. This study aimed to identify the predictive factors associated with ART adherence during the early months of treatment in rural Zambia. METHODS: This is a field based observational longitudinal study in Mumbwa district, which is located 150 km west of Lusaka, the capital of Zambia. Treatment naive patients aged over 15 years, who initiated treatment during September-November 2010, were enrolled. Patients were interviewed at the initiation and six weeks later. The treatment adherence was measured according to self-reporting by the patients. Multiple logistic regression analysis was performed to identify the predictive factors associated with the adherence. RESULTS: Of 157 patients, 59.9% were fully adherent to the treatment six weeks after starting ART. According to the multivariable analysis, full adherence was associated with being female [Adjusted Odds Ratio (AOR), 3.3; 95% Confidence interval (CI), 1.2-8.9], having a spouse who were also on ART (AOR, 4.4; 95% CI, 1.5-13.1), and experience of food insufficiency in the previous 30 days (AOR, 5.0; 95% CI, 1.8-13.8). Some of the most common reasons for missed doses were long distance to health facilities (n = 21, 53.8%), food insufficiency (n = 20, 51.3%), and being busy with other activities such as work (n = 15, 38.5%). CONCLUSIONS: The treatment adherence continues to be a significant challenge in rural Zambia. Social supports from spouses and people on ART could facilitate their treatment adherence. This is likely to require attention by ART services in the future, focusing on different social influences on male and female in rural Zambia. In addition, poverty reduction strategies may help to reinforce adherence to ART and could mitigate the influence of HIV infection for poor patients and those who fall into poverty after starting ART.