Clinical profile, referral trends, and real-world application of vibration-controlled transient elastography in children with non-alcoholic fatty liver disease in Singapore.

Background and Aim: Pediatric non-alcoholic fatty liver disease (NAFLD) is a progressive disorder that is increasing in incidence globally. The study aims to describe the clinical profile and longitudinal outcome, including the utility of vibration-controlled transient elastography (VCTE), in children with NAFLD at a single tertiary liver unit in Singapore. Methods: Retrospective review of patients aged 0-18 years referred for NAFLD from 2003 to 2020 was conducted. Diagnosis was based on persistent elevation of alanine transaminase ≥2× the upper limit of normal in at-risk patients, and/or radiologic detection of hepatic steatosis, with the exclusion of other etiologies. VCTE-derived liver stiffness measurements (LSMs) ≤7.0 , 7.1-9.0, and ≥9.1 kPa were used to differentiate normal (F0-F1), significant fibrosis (F2), and advanced fibrosis (F3-F4), respectively. Results: The study included 210 patients (72.4% male, mean age 11.6 years). New cases increased from 1.7/1000 referrals in 2003-2008 to 12.7 and 24.5/1000 referrals in 2009-2014 and 2015-2020, respectively. Significant proportion had dyslipidemia (41.4%), impaired glucose tolerance/diabetes (IGT/DM, 26.7%), and hypertension (17.1%). Only 6.2% had resolution of NAFLD after a mean follow-up of 3.7 years. Based on VCTE (n = 65), 41.5% had normal LSM, while 26.2% and 32.3% had increased likelihood of significant and advanced fibrosis, respectively. Age ≥16 years (odds ratio [OR] 8.9), IGT/DM (OR 6.5), and aspartate transaminase >70 U/L (OR 11.0) were independent risk factors associated with increased likelihood of advanced fibrosis. Conclusion: Incidence of pediatric NAFLD has increased dramatically in Singapore. Based on LSM estimation, pediatric NAFLD may be associated with an increased risk of developing advanced fibrosis by late adolescence.

Demographics, aetiology and outcome of paediatric acute liver failure in Singapore.

Introduction: The aetiology of paediatric acute liver failure (PALF) varies widely according to age, and geographic and socioeconomic factors. This study aimed to examine the epidemiology, aetiology and outcome of PALF in Singapore at a single centre. Methods: A retrospective review was performed of patients aged 0-18 years who were diagnosed with PALF from 2007 to 2019. PALF was defined by: absence of chronic liver disease; biochemical evidence of acute liver injury; and coagulopathy, non-correctible by vitamin K, defined as prothrombin time (PT) ≥20 seconds or international normalised ratio (INR) ≥2.0 regardless of hepatic encephalopathy (HE) or PT ≥15 seconds or INR ≥1.5 in the presence of HE. Results: 34 patients were included. Median age at diagnosis was 10 months (range 7 days to 156 months). The top three causes of PALF were indeterminate (41.2%), metabolic (26.5%) and infectious (26.5%) aetiologies. A metabolic disorder was the most frequent aetiology in infants <12 months (38.9%), whereas an indeterminate cause was the most common in children >12 months (50%). No cases of viral hepatitis A or B presenting with PALF were detected. Overall spontaneous recovery rate (survival without liver transplantation [LT]) was 38.2%, and overall mortality rate was 47.1%. Six patients underwent living-donor LT, and the post-transplant survival at one year was 83.3%. Conclusion: The aetiologic spectrum of PALF in Singapore is similar to that in developed Western countries, with indeterminate aetiology accounting for the majority. PALF is associated with poor overall survival; hence, timely LT for suitable candidates is critical to improve survival outcomes.

Somatic genetic rescue of a germline ribosome assembly defect.

Indirect somatic genetic rescue (SGR) of a germline mutation is thought to be rare in inherited Mendelian disorders. Here, we establish that acquired mutations in the EIF6 gene are a frequent mechanism of SGR in Shwachman-Diamond syndrome (SDS), a leukemia predisposition disorder caused by a germline defect in ribosome assembly. Biallelic mutations in the SBDS or EFL1 genes in SDS impair release of the anti-association factor eIF6 from the 60S ribosomal subunit, a key step in the translational activation of ribosomes. Here, we identify diverse mosaic somatic genetic events (point mutations, interstitial deletion, reciprocal chromosomal translocation) in SDS hematopoietic cells that reduce eIF6 expression or disrupt its interaction with the 60S subunit, thereby conferring a selective advantage over non-modified cells. SDS-related somatic EIF6 missense mutations that reduce eIF6 dosage or eIF6 binding to the 60S subunit suppress the defects in ribosome assembly and protein synthesis across multiple SBDS-deficient species including yeast, Dictyostelium and Drosophila. Our data suggest that SGR is a universal phenomenon that may influence the clinical evolution of diverse Mendelian disorders and support eIF6 suppressor mimics as a therapeutic strategy in SDS.

Analysis of Cholangitis Rates with Extended Perioperative Antibiotics and Adjuvant Corticosteroids in Biliary Atresia.

PURPOSE: There is no consensus regarding adjuvant therapies following Kasai portoenterostomy (KP) for biliary atresia (BA). This study aimed to analyze the effect of extended perioperative intravenous antibiotics (PI-Abx) and adjuvant corticosteroid on cholangitis and jaundice clearance rates in the 3 years post-KP in children with BA. METHODS: Data of patients who underwent KP between 1999-2018 at a single center were retrospectively analyzed. Group A (1999-2010) received PI-Abx for 5 days, Group B (2010-2012) received PI-Abx for 5 days plus low-dose prednisolone (2 mg/kg), and Group C (2012-2017) received PI-Abx for 14 days plus high-dose prednisolone (5 mg/kg). RESULTS: Fifty-four patients were included with groups A, B, and C comprising 25, 9, and 20 patients, respectively. The number of episodes of cholangitis was 1.0, 1.6, and 1.3 per patient (p=NS) within the first year and 1.8, 2.3, and 1.7 (p=NS) over 3 years in Groups A, B, and C, respectively. The jaundice clearance rate at 6 months was 52%, 78%, and 50% (p=NS), and the 3-year native liver survival (NLS) rate was 76%, 100%, and 80% (p=NS) in Groups A, B, and C, respectively. A near-significant association was observed between the incidence of cholangitis within the first year and decompensated liver cirrhosis/death at 3 years post KP (p=0.09). Persistence of jaundice at 6 months was significantly associated with decompensated cirrhosis/death at 3 years (p<0.001). CONCLUSION: The extended duration of PI-Abx and adjuvant corticosteroids was not associated with improved rates of cholangitis, jaundice clearance, or NLS in patients with BA.

Hepatocellular Carcinoma in the Absence of Cirrhosis in a Child With Inactive Chronic Hepatitis B Infection.

Chronic hepatitis B infection has been identified as an important risk factor for developing hepatocellular carcinoma (HCC) especially in the presence of hepatitis and liver cirrhosis. However, here we describe an unusual case of a child with chronic hepatitis B infection who developed HCC in the absence of active hepatitis or cirrhosis. This case serves to highlight the importance of regular HCC surveillance for all children with chronic hepatitis B, regardless of presence or absence of hepatitis or cirrhosis.

Heterozygous missense variant in EIF6 gene: A novel form of Shwachman-Diamond syndrome?

Shwachman-Diamond syndrome (SDS) is a rare multisystem ribosomal biogenesis disorder characterized by exocrine pancreatic insufficiency, hematologic abnormalities and bony abnormalities. About 90% of patients have biallelic mutations in SBDS gene. Three additional genes-EFL1, DNAJC21 and SRP54 have been reported in association with a SDS phenotype. However, the cause remains unknown for ~10% of patients. Herein, we report a 6-year-old Chinese boy, who presented in the neonatal period with pancytopenia, liver transaminitis with hepatosplenomegaly and developmental delay, and subsequently developed pancreatic insufficiency complicated by malabsorption and poor growth. Exome sequencing identified a novel de novo heterozygous variant in EIF6 (c.182G>T, p.Arg61Leu). EIF6 protein inhibits ribosomal maturation and is removed in the late steps of ribosomal maturation by SBDS and EFL1 protein. Given the interaction of EIF6 with SBDS and EFL1, we postulate heterozygous variants in EIF6 as a novel cause of Shwachman-Diamond-like phenotype. We compared the phenotype of our patient with those in patients with mutation in SBDS, EFL1, DNAJC21, and SRP54 genes to support this association. Identification of more cases of this novel phenotype would strengthen the association with the genetic etiology.

Conjugated hyperbilirubinemia presenting in first fourteen days in term neonates.

AIM: To describe the etiology and characteristics of early-onset conjugated hyperbilirubinemia (ECHB) presenting within 14 d of life in term neonates. METHODS: Retrospective review was performed of term infants up to 28-d-old who presented with conjugated hyperbilirubinemia (CHB) at a tertiary center over a 5-year period from January 2010 to December 2014. CHB is defined as conjugated bilirubin (CB) fraction greater than 15% of total bilirubin and CB greater or equal to 25 µmol/L. ECHB is defined as CHB detected within 14 d of life. "Late-onset" CHB (LCHB) is detected at 15-28 d of life and served as the comparison group. RESULTS: Total of 117 patients were recruited: 65 had ECHB, 52 had LCHB. Neonates with ECHB were more likely to be clinically unwell (80.0% vs 42.3%, P < 0.001) and associated with non-hepatic causes (73.8% vs 44.2%, P = 0.001) compared to LCHB. Multifactorial liver injury (75.0%) and sepsis (17.3%) were the most common causes of ECHB in clinically unwell infants, majority (87.5%) had resolution of CHB with no progression to chronic liver disease. Inborn errors of metabolism were rare (5.8%) but associated with high mortality (100%) in our series. In the subgroup of clinically well infants (n = 13) with ECHB, biliary atresia (BA) was the most common diagnosis (61.5%), all presented initially with normal stools and decline in total bilirubin but with persistent CHB. CONCLUSION: Secondary hepatic injury is the most common reason for ECHB. BA presents with ECHB in well infants without classical symptoms of pale stools and deep jaundice.

Serologic Responses After Hepatitis B Vaccination in Preterm Infants Born to Hepatitis B Surface Antigen-Positive Mothers: Singapore Experience.

BACKGROUND: The Advisory Committee on Immunization Practices (ACIP) recommends a 4-dose vaccination schedule for preterm low birth weight infants (<2 kg) and a 3-dose vaccination schedule for preterm infants (≥2 kg) born to hepatitis B surface antigen (HBsAg)-positive mothers. However, data remain limited for these high-risk infants, and the optimal dosing schedule in Asia is not well established. AIM: The aim of this study was to evaluate the serologic vaccine responses in preterm infants born to HBsAg-positive mothers using current vaccination guidelines. METHODS: Preterm babies of gestation less than 37 completed weeks born to HBsAg-positive mothers were prospectively recruited during 6 years (June 2009 to December 2015) and retrospectively recruited via convenience sampling in 2 years (June 2013 to April 2015) in 2 tertiary pediatric centers. The preterm infants were given 4 or 3 vaccine doses as per ACIP 2005 guidelines. Vaccine response was defined as achieving hepatitis B surface antibody values of >10 IU/L [Abbott Architect (Abbott Laboratories, Chicago, IL)] at 9 months of chronologic age. RESULTS: A total of 24 preterm infants were recruited. Four had a birth weight <2 kg. Of 23 surviving infants, all were negative for HBsAg. One baby (4.5%) did not achieve adequate vaccine response. All 4 infants with birth weight <2 kg achieved seroprotective values. CONCLUSION: The current ACIP-recommended vaccination schedule results in adequate antibody responses in preterm infants of HBsAg-positive mothers.

Seventeen years of Kasai portoenterostomy for biliary atresia in a single Southeast Asian paediatric centre.

AIM: Biliary atresia (BA) has preponderance in Asian populations with Kasai portoenterostomy (KP) regarded as the first-line standard of care. Yet reports from Southeast Asia remain scant. This study reviews the demographics, short- and medium-term outcomes for our cohort, and evaluates prognostic factors for outcome. METHODS: All patients diagnosed with BA between January 1997 and December 2013 were included. Clinical data were obtained from medical records. Jaundice clearance was defined as total bilirubin < 20 µmol/L within 6 months after KP. Two-year and 5-year native liver survival (NLS) were determined. Prognostic factors examined included gender, ethnicity, associated anomalies, age at KP, post-KP cholangitis and clearance of jaundice within 6 months. RESULTS: Of 58 patients studied, 31(53.4%) were male. Median age at time of KP was 53 days (range: 28-127). Ethnic distribution showed 32 (55.2%) Chinese, 16 (27.6%) Malays and 10 (17.2%) others. Twenty-one (36.2%) patients achieved jaundice clearance by 6 months. Two-year NLS rate was 36 out of 50 (72%), while 5-year NLS rate was 16 out of 35 (45.7%). Only clearance of jaundice within 6 months had a significant association with NLS (P = 0.006). All other factors showed no significant impact on outcome. CONCLUSIONS: Our short- and medium-term outcomes after KP for BA are comparable with those reported by most international centres. However, prognostic factors such as age at KP, cholangitis episodes and associated anomalies did not show significant correlation; only clearance of jaundice within 6 months was significantly predictive of NLS.

Incidence of rotavirus gastroenteritis by age in African, Asian and European children: Relevance for timing of rotavirus vaccination.

Variability in rotavirus gastroenteritis (RVGE) epidemiology can influence the optimal vaccination schedule. We evaluated regional trends in the age of RVGE episodes in low- to middle- versus high-income countries in three continents. We undertook a post-hoc analysis based on efficacy trials of a human rotavirus vaccine (HRV; Rotarix™, GSK Vaccines), in which 1348, 1641, and 5250 healthy infants received a placebo in Europe (NCT00140686), Africa (NCT00241644), and Asia (NCT00197210, NCT00329745). Incidence of any/severe RVGE by age at onset was evaluated by active surveillance over the first two years of life. Severity of RVGE episodes was assessed using the Vesikari-scale. The incidence of any RVGE in Africa was higher than in Europe during the first year of life (≤2.78% vs. ≤2.03% per month), but much lower during the second one (≤0.86% versus ≤2.00% per month). The incidence of severe RVGE in Africa was slightly lower than in Europe during the first year of life. Nevertheless, temporal profiles for the incidence of severe RVGE in Africa and Europe during the first (≤1.00% and ≤1.23% per month) and second (≤0.53% and ≤1.13% per month) years of life were similar to those of any RVGE. Any/severe RVGE incidences peaked at younger ages in Africa vs. Europe. In high-income Asian regions, severe RVGE incidence (≤0.31% per month) remained low during the study. The burden of any RVGE was higher earlier in life in children from low- to middle- compared with high-income countries. Differing rotavirus vaccine schedules are likely warranted to maximize protection in different settings.

Efficacy, Immunogenicity and Safety of a Human Rotavirus Vaccine RIX4414 in Singaporean Infants.

INTRODUCTION: This was the first study conducted to evaluate the efficacy of 2 oral doses of the human rotavirus vaccine, RIX4414 in Singaporean infants during the first 3 years of life. MATERIALS AND METHODS: Healthy infants, 11 to 17 weeks of age were enrolled in this randomised (1:1), double-blinded, placebo-controlled study to receive 2 oral doses of RIX4414 vaccine/placebo following a 0-, 1-month schedule. Vaccine efficacy against severe rotavirus (RV) gastroenteritis (Vesikari score ≥11) caused by wild-type RV strains from a period starting from 2 weeks post-Dose 2 until 2 and 3 years of age was calculated with 95% confidence interval (CI). Immunogenicity and safety of the vaccine were also assessed. RESULTS: Of 6542 infants enrolled, 6466 were included in the efficacy analysis and a subset of 100 infants was included in the immunogenicity analysis. Fewer severe RV gastroenteritis episodes were reported in the RIX4414 group when compared to placebo at both 2 and 3 year follow-up periods. Vaccine efficacy against severe RV gastroenteritis at the respective time points were 93.8% (95% CI, 59.9 to 99.9) and 95.2% (95% CI, 70.5 to 99.9). One to 2 months post-Dose 2 of RIX4414, 97.5% (95% CI, 86.8 to 99.9) of infants seroconverted for anti-RV IgA antibodies. The number of serious adverse events recorded from Dose 1 until 3 years of age was similar in both groups. CONCLUSION: Two oral doses of RIX4414 vaccine was immunogenic and provided high level of protection against severe RV gastroenteritis in Singaporean children, during the first 3 years of life when the disease burden is highest.

Prolonged hepatitis and jaundice: a rare complication of paediatric Epstein-Barr virus infection.

We herein report the case of a 14-year-old girl with Epstein-Barr virus (EBV) infectious mononucleosis who developed prolonged hepatitis and jaundice. At presentation, she had tender hepatomegaly with a markedly deranged liver function test. Abdominal ultrasonography showed hepatomegaly and a thickened gallbladder wall. During the subsequent 11 weeks, her transaminases showed two further peaks, which corresponded with clinical deterioration. Her highest alanine transaminase level was 1,795 µ/L and total bilirubin level was 154 µmol/L. She recovered fully with conservative management. EBV-related liver involvement is typically mild and self-limiting. We believe that tender hepatomegaly and gallbladder thickening may be important predictors of significant liver involvement. Although multiple transaminase peaks may occur, we do not consider this an indication for antiviral or immunosuppressive therapy. In the absence of strong evidence supporting the use of any specific therapy, we recommend a conservative approach for an immunocompetent patient.

Incidence of intussusception in Singaporean children aged less than 2 years: a hospital-based prospective study.

BACKGROUND: Continuous surveillance for intussusception (IS) is important for monitoring the safety of second-generation rotavirus vaccines. The present study aimed to assess the incidence of IS in Singaporean children aged < 2 years. METHODS: This was a prospective, hospital-based, multi-center surveillance conducted in seven hospitals - two public hospitals and five private medical centers between May 2002 and June 2010 in Singapore. Diagnosis of IS (definite, probable, possible, suspected) was based on the case definition developed by the Brighton Collaboration. Children < 2 years of age who were diagnosed with IS were enrolled in this study. Incidence of IS was calculated per 100,000 child-year with its 95% confidence interval. RESULTS: Of the 178 children enrolled, 167 children with definite IS cases were considered for final analyses; 11 were excluded (six diagnosed as probable IS and four diagnosed as suspected IS; one child's parents withdrew consent). Mean age of children with definite IS was 11.6 ± 6 months; 67.7% were males. The overall incidence of IS was 28.9 (95% CI: 23.0-34.8) and 26.1 (95% CI: 22.2-30.0) per 100,000 child-year in children < 1 year and < 2 years of age, respectively. The majority of IS cases (20 [12.0%]) were reported in children aged 6 months. Most children (98.2% [164/167]) recovered, two (1.2%) children recovered with sequelae and one (0.6%) child died of septic shock. CONCLUSIONS: The incidence of IS remained low and stable in Singaporean children aged < 2 years during the study period (May 2002 to June 2010). TRIAL REGISTRATION: NCT01177839.

A hospital-based surveillance of rotavirus gastroenteritis in children <5 years of age in Singapore.

BACKGROUND: In Singapore, 2 rotavirus vaccines were licensed in October 2005 and July 2007, respectively, for vaccinating infants aged ≥ 6 weeks against rotavirus gastroenteritis. These vaccines are optional and are not included in the National Childhood Immunization Program. This study aimed to determine the incidence of rotavirus gastroenteritis-associated hospitalizations among children <5 years of age. METHODS: Children <5 years, who were hospitalized for acute gastro enteritis, were enrolled between September 2005 and April 2008. Stool samples were tested for the presence and serotyping of rotavirus. Incidence and proportion of gastroenteritis and rotavirus gastroenteritis cases were calculated with 95% confidence intervals. RESULTS: Among 1976 children included in the according-to-protocol cohort, 781 were rotavirus positive with a median age of 24 months (range: 0-59 months). The overall incidence of rotavirus gastroenteritis hospitalizations during the entire study period in children <5 years of age was 4.6 (95% confidence interval: 4.3-4.9) per 1000 person-years with the highest number of cases observed in children 13-24 months of age (26.5%). G1P[8] (18.3%) and G9P[8] (9.9%) were the most common rotavirus types. Rotavirus gastroenteritis hospitalizations peaked between January and March. CONCLUSION: Rotavirus infection was the primary cause of acute gastro enteritis hospitalizations among children <5 years of age, constituting nearly one-third of gastroenteritis hospitalizations in Singapore. The predominant strain observed in Singapore was G1P[8]. Results of this study suggest the need for implementation of rotavirus vaccination into National Childhood Immunization Program in Singapore.

Cap polyposis: a rare cause of rectal bleeding in children.

AIM: To evaluate the clinicopathological features and treatment outcomes of cap polyposis in the pediatric population. METHODS: All pediatric patients with histologically proven diagnosis of cap polyposis were identified from our endoscopy and histology database over a 12 year period from 2000-2012 at our tertiary pediatric center, KK Women's and Children's Hospital in Singapore. The case records of these patients were retrospectively reviewed. The demographics, clinical course, laboratory results, endoscopic and histopathological features, treatments, and outcomes were analyzed. The study protocol was approved by the hospital institutional review board. The histological slides were reviewed by a pediatric histopathologist to confirm the diagnosis of cap polyposis. RESULTS: Eleven patients were diagnosed with cap polyposis. The median patient age was 13 years (range 5-17 years); the sample included 7 males and 4 females. All of the patients presented with bloody stools. Seven patients (63%) had constipation, while 4 patients (36%) had diarrhea. All of the patients underwent colonoscopy and polypectomies (excluding 1 patient who refused polypectomy). The macroscopic findings were of polypoid lesions covered by fibrinopurulent exudates with normal intervening mucosa. The rectum was the most common involvement site (n = 9, 82%), followed by the rectosigmoid colon (n = 3, 18%). Five (45%) patients had fewer than 5 polyps, and 6 patients (65%) had multiple polyps. Histological examination of these polyps showed surface ulcerations with a cap of fibrin inflammatory exudate. Four (80%) patients with fewer than 5 polyps had complete resolution of symptoms following the polypectomy. One patient who did not consent to the polypectomy had resolution of symptoms after being treated with sulphasalazine. All 6 patients with multiple polyps experienced recurrence of bloody stools on follow-up (mean = 28 mo). CONCLUSION: Cap polyposis is a rare and under-recognised cause of rectal bleeding in children. Our study has characterized the disease phenotype and treatment outcomes in a pediatric cohort.

Paediatric inflammatory bowel disease in a multiracial Asian country.

INTRODUCTION: This study examined the characteristics and trends in the incidence of inflammatory bowel disease (IBD) among children in Singapore. METHODS: We retrospectively reviewed all patients under 18 years diagnosed with IBD over a 14-year period. Information on demographics, disease presentation, laboratory findings, radiological investigations, and endoscopic and histological findings were obtained from the patients' medical records. RESULTS: 32 patients were diagnosed with IBD, 30 of whom had Crohn's disease and 2 had ulcerative colitis. The incidence of IBD rose from an initial rate of 2.2 per 100,000 patients in the year 2000 to a peak of 11.4 patients per 100,000 patients by 2008. Median age of onset of symptoms was 10.5 years. There were more boys (63%) than girls in the group and a higher representation of Indians (34.4%). The most common presenting symptoms were abdominal pain (87.5%), diarrhoea (75.0%) and weight loss (71.9%). Extraintestinal manifestations such as fever and arthralgia were found in over 50% of patients. The most common physical findings were perianal abnormalities (56.3%), mouth ulcers (37.5%) and growth failure (15.6%). Abnormal laboratory findings such as low albumin, raised erythrocyte sedimentation rate, anaemia, thrombocytosis and high C-reactive protein were found in nearly half of the patients. Endoscopic and histological findings showed that a majority of patients (90.6%) also had evidence of inflammation in the upper gastrointestinal tract. CONCLUSION: Paediatric IBD is on the rise. The higher occurrence in Indians, earlier onset and more florid presentation may suggest different genetic and environmental influences specific to Asian children.

Rotavirus vaccine RIX4414 efficacy sustained during the third year of life: a randomized clinical trial in an Asian population.

RIX4414 (Rotarix™), has shown high efficacy during the first 2-years of life. A 2-year randomized, double-blind, placebo-controlled trial in Singapore, Hong Kong, and Taiwan was extended for another year. Infants (6-17 weeks) received 2-doses (1-2 months apart) of RIX4414 (n=5359) or placebo (n=5349). During the third-year follow-up, 4359 (RIX4414) and 4328 (placebo) infants were monitored. 64 (1.2%) and 2 (0.04%) infants in the placebo and RIX4414 groups, respectively, reported severe rotavirus-gastroenteritis (RVGE), resulting in a vaccine efficacy of 96.9% (95% CI [88.3-99.6]). Efficacy was 100% (67.5-100) in the third-year. RIX4414 was efficacious against G1 (100.0% [84.8-100]) and pooled non-G1 RV types (94.9% [80.2-99.4]). This study shows that the vaccine is highly efficacious, regardless of circulating RV-types, up to the first 3 years of life in affluent Asian urban populations.