Seroprevalence of Antibodies to Measles, Mumps, and Rubella among Thai Population: Evaluation of Measles/MMR Immunization Programme

Stored serum specimens, from four regions of Thailand, of healthy children attending well baby clinics and of healthy people with acute illnesses visiting outpatient clinics were randomly sampled and tested for IgG antibody to measles, mumps, and rubella (MMR). The immunity patterns of rubella and mumps fitted well with the history of rubella and MMR vaccination, seroprotective rates being over 85% among those aged over seven years. A high proportion of younger children acquired the infection before the age of vaccination. MMR vaccination should preferably be given to children at an earlier age. For measles, 73% seroprotective rates among children, aged 8-14 years, who should have received two doses of measles/MMR vaccine, were lower than expected. This finding was consistent with the age-group reported in outbreaks of measles in Thailand. The apparent ineffectiveness (in relation to measles) of MMR immunization of 1st grade students warrants further studies

Economic evaluation of rotavirus vaccination:an important step of the introduction to the national immunization program in Thailand

Introduction World Health Organization recommends rotavirus vaccine for all national immunization programs (NIPs). To provide country-specific evidence, we conducted economic evaluation of a monovalent rotavirus vaccination using specific data of the pilot phase in Thailand. Method A Markov model was adopted to compare the 2020 birth cohort once receiving rotavirus vaccination versus no vaccination from healthcare and societal perspective over five years. Data on disease burden, vaccine effectiveness, costs, and utilities were taken from a cohort study in two provinces of Thailand. Sensitivity analyses were performed to test the robustness of the results. Results Rotavirus vaccination would reduce rotavirus diarrhea and costs of illness by 48% and 71%, respectively, over the first five years of life. At USD 13 per dose, vaccine was cost-effective with the ICERs of USD 4,114 and USD 1,571per QALY gained from healthcare and societal perspective, respectively. Results were sensitive to incidence and vaccine cost. The budget for vaccine purchasing was estimated at USD13 million per year. Conclusion Incorporating rotavirus vaccination into the NIP substantially reduced health and cost outcomes and was cost-effective for both perspectives. However, the government needs to negotiate vaccine price prior to program implementation to achieve favorable budget impact

Leptospirosis: Skin Wounds and Control Strategies, Thailand, 1999

After an outbreak of leptospirosis in workers who participated in cleaning a pond during September 1999 in Thailand, a serologic survey was conducted. Among a cohort of 104 persons from one village who participated in pond cleaning activity, 43 (41.3%) were seropositive for immunoglobulin M antibodies against Leptospira, indicating recent infection. Only 17 (39.5%) of 43 seropositive persons reported a recent febrile illness; the remaining seropositive persons were considered asymptomatic, suggesting that asymptomatic leptospirosis infection may be common where leptospirosis is endemic. Multivariable logistic regression indicated that wearing long pants or skirts was independently protective against leptospirosis infection (ORadjusted = 0.217), while the presence of more than two wounds on the body was independently associated with infection (ORadjusted = 3.97). Educational efforts should be enhanced in areas where leptospirosis is endemic to encourage the use of protective clothing. In addition wound management and avoidance of potentially contaminated water when skin wounds are present should be included in health education programs

Deliberations of the Strategic Advisory Group of Experts on Immunization on the use of CYD-TDV dengue vaccine.

The Strategic Advisory Group of Experts (SAGE) on Immunization advises WHO on global policies for vaccines. In April, 2016, SAGE issued recommendations on the use of the first licenced dengue vaccine, CYD-TDV. In November, 2017, a retrospective analysis of clinical trial data, stratifying participants according to their dengue serostatus before the first vaccine dose, showed that although in high seroprevalence settings the vaccine provides overall population benefit, there was an excess risk of severe dengue in seronegative vaccinees. SAGE's working group on dengue vaccines met to discuss the new data and mainly considered two vaccination strategies: vaccination of populations with dengue seroprevalence rates above 80% or screening of individuals before vaccination, and vaccinating only seropositive individuals. We report on the deliberations that informed the recommendation of the pre-vaccination screening strategy, in April, 2018. Important research and implementation questions remain for CYD-TDV, including the development of a highly sensitive and specific rapid diagnostic test to determine serostatus, simplified immunisation schedules, and assessment of the need for booster doses

Economic burden of rotavirus diarrhea in Thailand:Report from a pilot study on rotavirus vaccination

BACKGROUND: Rotavirus diarrhea is the leading cause of morbidity and mortality in young children in both developed and developing countries. Hospitalization costs are a significant burden of both governments and households. The objective of this study was to estimate the economic burden associated with the hospitalization of children with non-rotavirus and rotavirus diarrhea in two provinces in Thailand. METHOD: A prospective incidence-based cost-of-illness study was conducted on children under five years old with acute diarrhea who had been admitted to public hospitals in two provinces during October 2012 and June 2013. Caregivers were interviewed to estimate costs from a societal perspective at 2014 values. Stool samples were examined for rotavirus antigens. Multivariate regression analysis was used to assess the relationship of predictor variables to costs. Annual economic burden of rotavirus hospitalization was estimated by multiplying the number of hospitalized children and the hospitalization cost per episode. The costs were converted to international dollars (I$) using purchasing power parity (PPP) (1 USD = 12.36 baht for the year 2014). RESULTS: Seven hundred and eighty-eight cases of acute diarrhea were included in the analysis. Of the total, one hundred and ninety-seven (25%) were detected as being rotavirus positive. Total societal costs of inpatient care per episode were 822.68 USD (10,165 Baht). The average costs of children with and without rotavirus were 903.39 USD (11,162 Baht) and 795.40 USD (9,827 Baht), respectively. Based on the multiple regression analysis, rotavirus infection, severity, and younger age were significantly associated with the higher costs. CONCLUSION: Diarrhea, rotavirus diarrhea in particular, represents of a substantial economic burden in the society in Thailand. The accurate estimates that societal costs of the rotavirus diarrhea hospitalizations provide valuable input for considering a preventive program

Real-World Effectiveness of COVID-19 Vaccines against Severe Outcomes during the Period of Omicron Predominance in Thailand: A Test-Negative Nationwide Case–Control Study

Due to the widespread Omicron variant of SARS-CoV-2 in Thailand, the effectiveness of COVID-19 vaccines has become a major issue. The primary objective of this study is to examine the real-world effectiveness of COVID-19 vaccines based on secondary data acquired under normal circumstances in a real-world setting, to protect against treatment with invasive ventilation of pneumonia during January to April 2022, a period when Omicron was predominant. We conducted a nationwide test-negative case–control study. The case and control were matched with a ratio of 1:4 in terms of age, date of specimen collection, and hospital collection specimen and the odds ratio was calculated using conditional logistic regression. Overall, there was neither a distinction between mix-and-match regimens and homologous mRNA regimens against severe symptoms, nor was there a decline of the protective effect over the study period. The third and fourth dose boosters with ChAdOx1 nCoV-19 or mRNA vaccines provided high levels of protection against severe outcomes, approximately 87% to 100%, whereas two doses provided a moderate degree (70%). Thus, this study concludes that current national vaccine strategies provide favourable protective benefits against the Omicron variant. All Thais should receive at least two doses, while high-risk or vulnerable groups should be administered at least three doses

Real-World Effectiveness of Mix-and-Match Vaccine Regimens against SARS-CoV-2 Delta Variant in Thailand: A Nationwide Test-Negative Matched Case-Control Study

The objective of this study is to explore the real-world effectiveness of various vaccine regimens to tackle the epidemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant in Thailand during September–December 2021. We applied a test-negative case control study, using nationwide records of people tested for SARS-CoV-2. Each case was matched with two controls with respect to age, detection date, and specimen collection site. A conditional logistic regression was performed. Results were presented in the form vaccine effectiveness (VE) and 95% confidence interval. A total of 1,460,458 observations were analyzed. Overall, the two-dose heterologous prime-boost, ChAdOx1 + BNT162b2 and CoronaVac + BNT162b2, manifested the largest protection level (79.9% (74.0–84.5%) and 74.7% (62.8–82.8%)) and remained stable over the whole study course. The three-dose schedules (CoronaVac + CoronaVac + ChAdOx1, and CoronaVac + CoronaVac + BNT162b2) expressed very high degree of VE estimate (above 80.0% at any time interval). Concerning severe infection, almost all regimens displayed very high VE estimate. For the two-dose schedules, heterologous prime-boost regimens seemed to have slightly better protection for severe infection relative to homologous regimens. Campaigns to expedite the rollout of third-dose booster shot should be carried out. Heterologous prime-boost regimens should be considered as an option to enhance protection for the entire population

Reassortment of Human and Animal Rotavirus Gene Segments in Emerging DS-1-Like G1P[8] Rotavirus Strains.

The emergence and rapid spread of novel DS-1-like G1P[8] human rotaviruses in Japan were recently reported. More recently, such intergenogroup reassortant strains were identified in Thailand, implying the ongoing spread of unusual rotavirus strains in Asia. During rotavirus surveillance in Thailand, three DS-1-like intergenogroup reassortant strains having G3P[8] (RVA/Human-wt/THA/SKT-281/2013/G3P[8] and RVA/Human-wt/THA/SKT-289/2013/G3P[8]) and G2P[8] (RVA/Human-wt/THA/LS-04/2013/G2P[8]) genotypes were identified in fecal samples from hospitalized children with acute gastroenteritis. In this study, we sequenced and characterized the complete genomes of strains SKT-281, SKT-289, and LS-04. On whole genomic analysis, all three strains exhibited unique genotype constellations including both genogroup 1 and 2 genes: G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 for strains SKT-281 and SKT-289, and G2-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 for strain LS-04. Except for the G genotype, the unique genotype constellation of the three strains (P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2) is commonly shared with DS-1-like G1P[8] strains. On phylogenetic analysis, nine of the 11 genes of strains SKT-281 and SKT-289 (VP4, VP6, VP1-3, NSP1-3, and NSP5) appeared to have originated from DS-1-like G1P[8] strains, while the remaining VP7 and NSP4 genes appeared to be of equine and bovine origin, respectively. Thus, strains SKT-281 and SKT-289 appeared to be reassortant strains as to DS-1-like G1P[8], animal-derived human, and/or animal rotaviruses. On the other hand, seven of the 11 genes of strain LS-04 (VP7, VP6, VP1, VP3, and NSP3-5) appeared to have originated from locally circulating DS-1-like G2P[4] human rotaviruses, while three genes (VP4, VP2, and NSP1) were assumed to be derived from DS-1-like G1P[8] strains. Notably, the remaining NSP2 gene of strain LS-04 appeared to be of bovine origin. Thus, strain LS-04 was assumed to be a multiple reassortment strain as to DS-1-like G1P[8], locally circulating DS-1-like G2P[4], bovine-like human, and/or bovine rotaviruses. Overall, the great genomic diversity among the DS-1-like G1P[8] strains seemed to have been generated through reassortment involving human and animal strains. To our knowledge, this is the first report on whole genome-based characterization of DS-1-like intergenogroup reassortant strains having G3P[8] and G2P[8] genotypes that have emerged in Thailand. Our observations will provide important insights into the evolutionary dynamics of emerging DS-1-like G1P[8] strains and related reassortant ones