Distribution of rotavirus strains and strain-specific effectiveness of the rotavirus vaccine after its introduction: a systematic review and meta-analysis

Effectiveness of monovalent rotavirus vaccine against hospital-attended rotavirus gastroenteritis among children in Uganda

BACKGROUND

The underlying causes for lower rotavirus vaccine effectiveness (VE) in high-child-mortality settings are not well understood. Uganda introduced the human monovalent G1P[8] rotavirus vaccine (Rotarix) in June 2018. We determined the effectiveness of Rotarix against rotavirus diarrhea requiring hospital care among Ugandan children.

METHODS

We compared the vaccination status of children with laboratory-confirmed rotavirus (cases) and non-rotavirus (controls) diarrhea who were age-eligible to receive Rotarix and admitted to 3 hospitals in Uganda October 2018-December 2022. VE ([1-odds ratio of vaccination among cases and controls] x 100]) was calculated using unconditional logistic regression adjusting for age, birth month-year, and hospital.

RESULTS

Among 187 cases and 622 controls, respectively, 93 % (173/187) and 93 % (579/622) had received ≥1 doses of Rotarix. Adjusted full-series (2 dose) VE against rotavirus diarrhea was 29 % (95 % confidence interval: -37 %-63 %) in children 4-59 months of age. Two-dose VE was 62 % (9 %-84 %) in infants 4-11 months of age and - 69 % (-401 %-43 %) in children 12-59 months of age (P = 0.20). VE against strains partially-heterotypic to the vaccine strain (including G3P[8], the most common curculating genotype) was 59 % (1 %-83 %).

CONCLUSIONS

Routine Rotarix vaccination was effective in preventing hospital visits for rotavirus diarrhea among Ugandan infants, although protection was not sustained after the first year of life. Protection was demonstrated against partially heterotypic rotavirus strains. These results support the continued use of rotavirus vaccines in Uganda. Additional studies are needed to understand the lower rotavirus VE seen in Uganda and other high-mortality settings.

Study of rotavirus genotypes G and P in one Egyptian center-cross-sectional study

BACKGROUND

Rotavirus-associated gastroenteritis is a common health problem in children, different variations of rotavirus genotypes differ according to geographic locations and the practice of wide-scale vaccination. Therefore, the present study aimed to detect both the G and P genotypes of rotavirus in children ≤ 5 years old in one center in Egypt as a cross-sectional study, to correlate the genotypes with various demographic and clinical data in infected children and to evaluate the common mixed genotypes G and P in infected children.

METHOD

The cross-sectional study included children with acute gastroenteritis ≤ 5 years old from January 2023 till March 2024 recruited from Mansoura University Children's Hospital, Egypt based upon laboratory diagnosis by exclusion of bacterial and protozoa pathogens. The stool samples were obtained from each child and subjected to detection of rotavirus antigen by enzyme-linked immunosorbent assay (ELISA) followed by genotypes identification of G and P genotypes by nested polymerase chain reaction (PCR).

RESULT

A nested PCR study for rotavirus genotypes revealed that G1 was the most common genotype (24.7%) followed by G2 (21.1%), G3 (20%), G9 (20%), and G4 (14.1%). The genotyping of the P genotype revealed that P9 was the commonest genotype (24.7%), followed by P4 (21.2%), P10 (20%), P8 (17.6%) and P6 (16.5%). The commonest combined genotypes of G and P were G1P4 (85.7%), G3P8(88.2%), followed by G2P6 (77.8%) and G9P9(76.5%) and G4P9 (66.7%) followed by G4P10 (33.3%), G9P10(23.5%), G2P10(22.2%), G1P10 (14.3%), G3P10(11.8%). The distribution was significant (P = 0.001). The positive rotavirus antigen was more frequently detected in females (55.3%) than males (44.7%, Odd ratio 0.2, 95% CI 0.22-0.71, P = 0.001). There was a significant association between the summer season and positive rotavirus antigen (P = 0.001) and rural residence of the patients (Odd ratio 6,9 95%CI 3,5-13.5, P = 0.001). The significant associated clinical sign with positive rotavirus antigen was fever (Odd ratio 3,3, 95%CI 1,8-6.05, P = 0.001). The genotypes G and P were significantly associated with positive rotavirus antigen as all cases positive by antigen had been detected by nested PCR with the commonest genotypes G4 (24.7%, P = 0.001) and genotype P9 (24.7%, P = 0.001).

CONCLUSION

The present study highlights the common genotypes of rotavirus at one center in Egypt, G1, G2, and G3 were the commonest G genotypes. As regard genotype P the commonest genotypes were P9, P4, and P10. The commonest combined genotypes were G1P4, G3P8, G2P6. There was no effect of the practice of rotavirus vaccination at limited rates at private health sections as the rotavirus is still a major pathogen of acute gastroenteritis in children. There is a need for the inclusion of rotavirus vaccination in the national program of children vaccination in Egypt.

Effectiveness and impact of monovalent rotavirus vaccination in Afghanistan: a test-negative case-control analysis

BACKGROUND

Afghanistan introduced monovalent rotavirus vaccine (Rotarix) into its national immunisation schedule in January, 2018. While post-licensure studies have shown substantial declines in rotavirus gastroenteritis cases and deaths globally, there is little evidence of rotavirus vaccine effectiveness and impact from low-income countries in Asia. We aimed to evaluate the effectiveness of the Rotarix vaccine and the impact of Rotarix vaccine on rotavirus gastroenteritis hospitalisations (ie, hospital admissions) among children younger than 5 years in Afghanistan.

METHODS

We used a test-negative case-control design embedded in an active sentinel surveillance platform to evaluate vaccine effectiveness. Children born on or after Jan 1, 2018, who had documentation of their rotavirus vaccination status and who were admitted for acute gastroenteritis at one of four sentinel hospitals from May, 2018 to December, 2021 were eligible to be included. We used an unconditional logistic regression model to estimate vaccine effectiveness and 95% CIs for a complete series of doses compared with no rotavirus vaccine doses among patients admitted with acute gastroenteritis. Vaccine effectiveness against hospitalisation was calculated as (1 - [odds of being vaccinated in cases] / [odds of being vaccinated in controls]) × 100%. We compared pre-vaccine (2013-15) and post-vaccine (2019-21) surveillance data from two sites to calculate vaccine impact.

FINDINGS

The vaccine effectiveness analysis included 1172 cases and 2173 controls. Approximately 2108 (63·0%) of 3345 cases and controls were male, 1237 (37·0%) were female, and 2171 (65·0%) were aged 6-11 months. Two doses of Rotarix were 45% (95% CI 22-62) effective against rotavirus hospitalisation in children aged 6-59 months, adjusting for age, severity, admission year, and rotavirus season. Rotavirus positivity decreased from 51% pre-vaccine to 39% post-vaccine, resulting in a 39% adjusted reduction in rotavirus positivity among children younger than 5 years admitted with acute gastroenteritis.

INTERPRETATION

Rotarix showed moderate effectiveness in preventing rotavirus gastroenteritis hospitalisations, consistent with findings in other low-income countries. These findings support the continued administration of the rotavirus vaccine in Afghanistan.

FUNDING

Gavi, the Vaccine Alliance.

TRANSLATION

For the Dari translation of the abstract see Supplementary Materials section.

Rotavirus Genotypes in the Postvaccine Era: A Systematic Review and Meta-analysis of Global, Regional, and Temporal Trends by Rotavirus Vaccine Introduction

BACKGROUND

Even moderate differences in rotavirus vaccine effectiveness against nonvaccine genotypes may exert selective pressures on circulating rotaviruses. Whether this vaccine effect or natural temporal fluctuations underlie observed changes in genotype distributions is unclear.

METHODS

We systematically reviewed studies reporting rotavirus genotypes from children <5 years of age globally between 2005 and 2023. We compared rotavirus genotypes between vaccine-introducing and nonintroducing settings globally and by World Health Organization (WHO) region, calendar time, and time since vaccine introduction.

RESULTS

Crude pooling of genotype data from 361 studies indicated higher G2P[4], a nonvaccine genotype, prevalence in vaccine-introducing settings, both globally and by WHO region. This difference did not emerge when examining genotypes over time in the Americas, the only region with robust longitudinal data. Relative to nonintroducing settings, G2P[4] detections were more likely in settings with recent introduction (eg, 1-2 years postintroduction adjusted odds ratio [aOR], 4.39; 95% confidence interval [CI], 2.87-6.72) but were similarly likely in settings with more time elapsed since introduction, (eg, 7 or more years aOR, 1.62; 95% CI, .49-5.37).

CONCLUSIONS

When accounting for both regional and temporal trends, there was no substantial evidence of long-term vaccine-related selective pressures on circulating genotypes. Increased prevalence of G2P[4] may be transient after rotavirus vaccine introduction.

Prevalence and genetic diversity of rotavirus among children under 5 years of age in China: a meta-analysis

Background

This meta-analysis was performed to assess the prevalence and circulating strains of rotavirus (RV) among Chinese children under 5 years of age after the implantation of the RV vaccine.

Material and methods

Studies published between 2019 and 2023, focused on RV-based diarrhea among children less than 5 years were systematically reviewed using PubMed, Embase, Web of Science, CNKI, Wanfang and SinoMed Data. We synthesized their findings to examine prevalence and genetic diversity of RV after the RV vaccine implementation using a fixed-effects or random-effects model.

Results

Seventeen studies met the inclusion criteria for this meta-analysis. The overall prevalence of RV was found to be 19.00%. The highest infection rate was noted in children aged 12-23months (25.79%), followed by those aged 24-35 months (23.91%), and 6-11 months (22.08%). The serotype G9 emerged as the most predominant RV genotype, accounting for 85.48% of infections, followed by G2 (7.70%), G8 (5.74%), G1 (4.86%), and G3 (3.21%). The most common P type was P[8], representing 64.02% of RV cases. Among G-P combinations, G9P[8] was the most frequent, responsible for 78.46% of RV infections, succeeded by G8P[8] (31.22%) and G3P[8] (8.11%).

Conclusion

Despite the variation of serotypes observed in China, the G1, G2, G3, G8 and G9 serotypes accounted for most RV strains. The genetic diversity analysis highlights the dynamic nature of RV genotypes, necessitating ongoing surveillance to monitor changes in strain distribution and inform future vaccine strategies.

Equine Rotavirus A under the One Health Lens: Potential Impacts on Public Health

Group A rotaviruses are a well-known cause of viral gastroenteritis in infants and children, as well as in many mammalian species and birds, affecting them at a young age. This group of viruses has a double-stranded, segmented RNA genome with high genetic diversity linked to point mutations, recombination, and, importantly, reassortment. While initial molecular investigations undertaken in the 1900s suggested host range restriction among group A rotaviruses based on the fact that different gene segments were distributed among different animal species, recent molecular surveillance and genome constellation genotyping studies conducted by the Rotavirus Classification Working Group (RCWG) have shown that animal rotaviruses serve as a source of diversification of human rotavirus A, highlighting their zoonotic potential. Rotaviruses occurring in various animal species have been linked with contributing genetic material to human rotaviruses, including horses, with the most recent identification of equine-like G3 rotavirus A infecting children. The goal of this article is to review relevant information related to rotavirus structure/genomic organization, epidemiology (with a focus on human and equine rotavirus A), evolution, inter-species transmission, and the potential zoonotic role of equine and other animal rotaviruses. Diagnostics, surveillance and the current status of human and livestock vaccines against RVA are also reviewed.

Rotavirus in developing countries: molecular diversity, epidemiological insights, and strategies for effective vaccination

Rotavirus (RV) causes the loss of numerous children's lives worldwide each year, and this burden is particularly heavy in low- and lower-middle-income countries where access to healthcare is limited. RV epidemiology exhibits a diverse range of genotypes, which can vary in prevalence and impact across different regions. The human genotypes that are most commonly recognized are G1P[8], G2P[4], G3P[8], G4P[8], G8P[8], G9P[8], and G12P[8]. The diversity of rotavirus genotypes presents a challenge in understanding its global distribution and developing effective vaccines. Oral, live-attenuated rotavirus vaccines have undergone evaluation in various contexts, encompassing both low-income and high-income populations, demonstrating their safety and effectiveness. Rotavirus vaccines have been introduced and implemented in over 120 countries, offering an opportunity to assess their effectiveness in diverse settings. However, these vaccines were less effective in areas with more rotavirus-related deaths and lower economic status compared to wealthier regions with fewer rotavirus-related deaths. Despite their lower efficacy, rotavirus vaccines significantly decrease the occurrence of diarrheal diseases and related mortality. They also prove to be cost-effective in regions with a high burden of such diseases. Regularly evaluating the impact, influence, and cost-effectiveness of rotavirus vaccines, especially the newly approved ones for worldwide use, is essential for deciding if these vaccines should be introduced in countries. This is especially important in places with limited resources to determine if a switch to a different vaccine is necessary. Future research in rotavirus epidemiology should focus on a comprehensive understanding of genotype diversity and its implications for vaccine effectiveness. It is crucial to monitor shifts in genotype prevalence and their association with disease severity, especially in high-risk populations. Policymakers should invest in robust surveillance systems to monitor rotavirus genotypes. This data can guide vaccine development and public health interventions. International collaboration and data sharing are vital to understand genotype diversity on a global scale and facilitate the development of more effective vaccines.

Impact of rotavirus vaccination on diarrheal disease burden of children in South America

INTRODUCTION

Rotavirus is a leading cause of severe diarrheal disease and death in children under five years of age worldwide. Vaccination is one of the most important public health interventions to reduce this significant burden.

AREAS COVERED

This literature review examined vaccination coverage, hospitalization rate, mortality, genotypic distribution, immunogenicity, cost-effectiveness, and risk versus benefit of rotavirus vaccination in children in South America. Nine out of twelve countries in South America currently include a rotavirus vaccine in their national immunization program with coverage rates in 2022 above 90%.

EXPERT OPINION

Introduction of the rotavirus vaccination has led to a marked reduction in hospitalizations and deaths from diarrheal diseases in children under 5 years, particularly infants under 1 year, in several South American countries. In Brazil, hospitalizations decreased by 59% and deaths by 21% (30-38% in infants). In Peru, hospitalizations in infants fell by 46% and deaths by 37% (56% in infants). Overall, data suggest that rotavirus vaccination has reduced rotavirus deaths by 15-50% in various South American countries. There is some evidence that immunity wanes after the age of 1-year old. Ongoing surveillance of vaccine coverage and changes in morbidity and mortality is important to maximize protection against this disease.

Lactobacillus acidophilus Expressing Murine Rotavirus VP8 and Mucosal Adjuvants Induce Virus-Specific Immune Responses

Rotavirus diarrhea-associated illness remains a major cause of global death in children under five, attributable in part to discrepancies in vaccine performance between high- and low-middle-income countries. Next-generation probiotic vaccines could help bridge this efficacy gap. We developed a novel recombinant Lactobacillus acidophilus (rLA) vaccine expressing rotavirus antigens of the VP8* domain from the rotavirus EDIM VP4 capsid protein along with the adjuvants FimH and FliC. The upp-based counterselective gene-replacement system was used to chromosomally integrate FimH, VP8Pep (10 amino acid epitope), and VP8-1 (206 amino acid protein) into the L. acidophilus genome, with FliC expressed from a plasmid. VP8 antigen and adjuvant expression were confirmed by flow cytometry and Western blot. Rotavirus naïve adult BALB/cJ mice were orally immunized followed by murine rotavirus strain ECWT viral challenge. Antirotavirus serum IgG and antigen-specific antibody-secreting cell responses were detected in rLA-vaccinated mice. A day after the oral rotavirus challenge, fecal antigen shedding was significantly decreased in the rLA group. These results indicate that novel rLA constructs expressing VP8 can be successfully constructed and used to generate modest homotypic protection from rotavirus challenge in an adult murine model, indicating the potential for a probiotic next-generation vaccine construct against human rotavirus.

Rotavirus genotypes in children under five years hospitalized with diarrhea in low and middle-income countries: Results from the WHO-coordinated Global Rotavirus Surveillance Network

Rotavirus is the most common pathogen causing pediatric diarrhea and an important cause of morbidity and mortality in low- and middle-income countries. Previous evidence suggests that the introduction of rotavirus vaccines in national immunization schedules resulted in dramatic declines in disease burden but may also be changing the rotavirus genetic landscape and driving the emergence of new genotypes. We report genotype data of more than 16,000 rotavirus isolates from 40 countries participating in the Global Rotavirus Surveillance Network. Data from a convenience sample of children under five years of age hospitalized with acute watery diarrhea who tested positive for rotavirus were included. Country results were weighted by their estimated rotavirus disease burden to estimate regional genotype distributions. Globally, the most frequent genotypes identified after weighting were G1P[8] (31%), G1P[6] (8%) and G3P[8] (8%). Genotypes varied across WHO Regions and between countries that had and had not introduced rotavirus vaccine. G1P[8] was less frequent among African (36 vs 20%) and European (33 vs 8%) countries that had introduced rotavirus vaccines as compared to countries that had not introduced. Our results describe differences in the distribution of the most common rotavirus genotypes in children with diarrhea in low- and middle-income countries. G1P[8] was less frequent in countries that had introduced the rotavirus vaccine while different strains are emerging or re-emerging in different regions.

Prevalence and genetic diversity of rotavirus in Bangladesh during pre-vaccination period, 1973-2023: a meta-analysis

Introduction

Rotavirus infection is a major cause of mortality among children under 5 years in Bangladesh. There is lack of integrated studies on rotavirus prevalence and genetic diversity during 1973 to 2023 in Bangladesh.

Methods

This meta-analysis was conducted to determine the prevalence, genotypic diversity and seasonal distribution of rotavirus during pre-vaccination period in Bangladesh. This study included published articles on rotavirus A, rotavirus B and rotavirus C. We used Medline, Scopus and Google Scholar for published articles. Selected literatures were published between 1973 to 2023.

Results

This study detected 12431 research articles published on rotavirus. Based on the inclusion criteria, 29 of 75 (30.2%) studies were selected. Molecular epidemiological data was taken from 29 articles, prevalence data from 29 articles, and clinical symptoms from 19 articles. The pooled prevalence of rotavirus was 30.1% (95% CI: 22%-45%, p = 0.005). Rotavirus G1 (27.1%, 2228 of 8219) was the most prevalent followed by G2 (21.09%, 1733 of 8219), G4 (11.58%, 952 of 8219), G9 (9.37%, 770 of 8219), G12 (8.48%, 697 of 8219), and G3 (2.79%, 229 of 8219), respectively. Genotype P[8] (40.6%, 2548 of 6274) was the most prevalent followed by P[4] (12.4%, 777 of 6274) and P[6] (6.4%, 400 of 6274), respectively. Rotavirus G1P[8] (19%) was the most frequent followed by G2P [4] (9.4%), G12P[8] (7.2%), and G9P[8], respectively. Rotavirus infection had higher odds of occurrence during December and February (aOR: 2.86, 95% CI: 2.43-3.6, p = 0.001).

Discussion

This is the first meta-analysis including all the studies on prevalence, molecular epidemiology, and genetic diversity of rotavirus from 1973 to 2023, pre-vaccination period in Bangladesh. This study will provide overall scenario of rotavirus genetic diversity and seasonality during pre-vaccination period and aids in policy making for rotavirus vaccination program in Bangladesh. This work will add valuable knowledge for vaccination against rotavirus and compare the data after starting vaccination in Bangladesh.

Elucidating the conformational dynamics of histo-blood group antigens and their interactions with the rotavirus spike protein through computational lens

In the present study, we investigated the conformational dynamics of histo-blood group antigens (HBGAs) and their interactions with the VP8* domain of four rotavirus genotypes (P[4], P[6], P[19], and P[11]) utilizing all-atom molecular dynamics simulations in explicit water. Our study revealed distinct changes in the dynamic behavior of the same glycan due to linkage variations. We observed that LNFPI HBGA having a terminal β linkage shows two dominant conformations after complexation, whereas only one was obtained for LNFPI with a terminal α linkage. Interestingly, both variants displayed a single dominant structure in the free state. Similarly, LNT and LNnT show a shift in their dihedral linkage profile between their two terminal monosaccharides because of a change in the linkage from β(1-3) to β(1-4). The molecular mechanics generalized Born surface area (MM/GBSA) calculations yielded the highest binding affinity for LNFPI(β)/P[6] (-13.93 kcal/mol) due to the formation of numerous hydrogen bonds between VP8* and HBGAs. LNnT binds more strongly to P[11] (-12.88 kcal/mol) than LNT (-4.41 kcal/mol), suggesting a single change in the glycan linkage might impact its binding profile significantly. We have also identified critical amino acids and monosaccharides (Gal and GlcNAc) that contributed significantly to the protein-ligand binding through the per-residue decomposition of binding free energy. Moreover, we found that the interaction between the same glycan and different protein receptors within the same rotavirus genogroup influenced the micro-level dynamics of the glycan. Overall, our study helps a deeper understanding of the H-type HBGA and rotavirus spike protein interaction.Communicated by Ramaswamy H. Sarma.

Corrected and republished from: "VP4 Is a Determinant of Alpha-Defensin Modulation of Rotaviral Infection"

IMPORTANCE

Rotavirus is a leading cause of severe diarrhea in young children. Like other fecal-oral pathogens, rotaviruses encounter abundant, constitutively expressed defensins in the small intestine. These peptides are a vital part of the vertebrate innate immune system. By investigating the impact that defensins from multiple species have on the infectivity of different strains of rotavirus, we show that some rotaviral infections can be inhibited by defensins. We also found that rotaviruses may have evolved resistance to defensins in the intestine of their host species, and some even appropriate defensins to increase their infectivity. Because rotaviruses infect a broad range of animals and rotaviral infections are highly prevalent in children, identifying immune defenses against infection and how they vary across species and among viral genotypes is important for our understanding of the evolution, transmission, and zoonotic potential of these viruses as well as the improvement of vaccines.

Association between Immunogenicity of a Monovalent Parenteral P2-VP8 Subunit Rotavirus Vaccine and Fecal Shedding of Rotavirus following Rotarix Challenge during a Randomized, Double-Blind, Placebo-Controlled Trial

A correlate of protection for rotavirus (RV) has not been consistently identified. Shedding of RV following an oral rotavirus vaccine (ORV) challenge has been investigated as a potential model to assess protection of parenteral RV vaccines. We previously showed that shedding of a challenge ORV dose was significantly reduced among recipients of a parenteral monovalent RV subunit vaccine (P2-VP8-P[8]) compared to placebo recipients. This secondary data analysis assessed the association between fecal shedding of RV, as determined by ELISA one week after receipt of a Rotarix challenge dose at 18 weeks of age, and serum RV-specific antibody responses, one and six months after vaccination with the third dose of the P2-VP8-P[8] vaccine or placebo. We did not find any association between serum RV-specific immune responses measured one month post-P2-VP8-P[8] vaccination and fecal shedding of RV post-challenge. At nine months of age, six months after the third P2-VP8-P[8] or placebo injection and having received three doses of Rotarix, infants shedding RV demonstrated higher immune responses than non-shedders, showing that RV shedding is reflective of vaccine response following ORV. Further evaluation is needed in a larger sample before fecal shedding of an ORV challenge can be used as a measure of field efficacy in RV vaccine trials.

Effectiveness of Pentavalent Rotavirus Vaccine in Shanghai, China: A Test-Negative Design Study

OBJECTIVE

To evaluate vaccine effectiveness (VE) of a live oral pentavalent rotavirus vaccine (RotaTeq, RV5) among young children in Shanghai, China, via a test-negative design study.

STUDY DESIGN

We consecutively recruited children visiting a tertiary children's hospital for acute diarrhea from November 2021 to February 2022. Information on clinical data and rotavirus vaccination was collected. Fresh fecal samples were obtained for rotavirus detection and genotyping. To evaluate VE of RV5 against rotavirus gastroenteritis among young children, unconditional logistic regression models were conducted to compare ORs for vaccination between rotavirus-positive cases and test-negative controls.

RESULTS

A total of 390 eligible children with acute diarrhea were enrolled, including 45 (11.54%) rotavirus-positive cases and 345 (88.46%) test-negative controls. After excluding 4 cases (8.89%) and 55 controls (15.94%) who had received the Lanzhou lamb rotavirus vaccine, 41 cases (12.39%) and 290 controls (87.61%) were included for the evaluation of RV5 VE. After adjustment for potential confounders, the 3-dose RV5 vaccination showed 85% (95% CI, 50%-95%) VE against mild to moderate rotavirus gastroenteritis among children aged 14 weeks to ≤4 years and 97% (95% CI, 83%-100%) VE among children aged 14 weeks to ≤2 years with genotypes G8P8, G9P8, and G2P4 represented 78.95%, 18.42%, and 2.63% of circulation strains, respectively.

CONCLUSIONS

A 3-dose vaccination of RV5 is highly protective against rotavirus gastroenteritis among young children in Shanghai. The G8P8 genotype prevailled in Shanghai after RV5 introduction.

Molecular epidemiology of rotavirus among children in Western Canada: Dynamic changes in genotype prevalence in four consecutive seasons

Rotavirus molecular surveillance remains important in the postvaccine era to monitor the changes in transmission patterns, identify vaccine-induced antigenic changes and discover potentially pathogenic vaccine-related strains. The Canadian province of Alberta introduced rotavirus vaccination into its provincial vaccination schedule in June 2015. To evaluate the impact of this program on stool rotavirus positivity rate, strain diversity, and seasonal trends, we analyzed a prospective cohort of children with acute gastroenteritis recruited between December 2014 and August 2018. We identified dynamic changes in rotavirus positivity and genotype trends during pre- and post-rotavirus vaccine introduction periods. Genotypes G9P[8], G1P[8], G2P[4], and G12P[8] predominated consecutively each season with overall lower rotavirus incidence rates in 2016 and 2017. The demographic and clinical features of rotavirus gastroenteritis were comparable among wild-type rotaviruses; however, children with G12P[8] infections were older (p < 0.001). Continued efforts to monitor changes in the molecular epidemiology of rotavirus using whole genome sequence characterization are needed to further understand the impact of the selection pressure of vaccination on rotavirus evolution.

Circulation of Vaccine-derived Rotavirus G1P[8] in a Vulnerable Child Cohort in Rio de Janeiro

BACKGROUND

The expansion of rotavirus (RV) immunization in several countries reduced the burden of acute diarrheal disease (ADD) and diarrhea-associated mortality. Although community transmission of live attenuated monovalent rotavirus vaccine (G1P[8] RV1) virus has been demonstrated in children and household contacts, fecal shedding of these strains in neonates and infants under six weeks of age has never been demonstrated. The objective of the study was to assess ADD and rotavirus vaccine strain shedding before and after immunization through 24 months of age.

METHODS

This was a prospective cohort study in a low-resource community in which stool samples were collected from neonates from 15 to 45 days of age every 2 weeks, after both doses of G1P[8] RV1, and in subsequent ADD episodes until 2 years of age. RV was detected and genotyped in stool samples by RT-PCR.

RESULTS

We enrolled 242 participants who were followed for an average of 23 months. The specific prevalence of G1P[8] RV1 virus was 3.3% in neonates and infants less than six weeks of age, 50% after the first dose, and 25.6% after the second dose. Among the 70 participants with ADD, G1P[8] RV1 virus was identified in only one participant (1.4% prevalence).

CONCLUSIONS

In vaccinated children, there were no breakthrough infections with G1P[8] RV1 and ADD was rare supporting high vaccine effectiveness. We observed G1P[8] RV1 virus shedding among neonates and infants before the first vaccine dose, providing evidence of transmission of the vaccine strain from immunized children to those who are not yet vaccinated.

Established and new rotavirus vaccines: a comprehensive review for healthcare professionals

Robust scientific evidence related to two rotavirus (RV) vaccines available worldwide demonstrates their significant impact on RV disease burden. Improving RV vaccination coverage may result in better RV disease control. To make RV vaccination accessible to all eligible children worldwide and improve vaccine effectiveness in high-mortality settings, research into new RV vaccines continues. Although current and in-development RV vaccines differ in vaccine design, their common goal is the reduction of RV disease risk in children <5 years old for whom disease burden is the most significant. Given the range of RV vaccines available, informed decision-making is essential regarding the choice of vaccine for immunization. This review aims to describe the landscape of current and new RV vaccines, providing context for the assessment of their similarities and differences. As data for new vaccines are limited, future investigations will be required to evaluate their performance/added value in a real-world setting.

Rotavirus genotypes and clinical outcome of natural infection based on vaccination status in the post-vaccine era

Rotavirus (RV) is a leading cause of gastroenteritis in children. In Japan, Rotarix (RV1; GlaxoSmithKline), which is a monovalent vaccine derived from human RV (G1P[8]), has been introduced since November 2011, and RotaTeq (RV5; MSD) which is an pentavalent, human-bovine mono-reassortant vaccine (G1, G2, G3, G4, and P1A[8]), has been introduced since July 2012. Long-term follow-up on vaccine efficacy and RV genotypical change should be carried out in order to control RV infection. The RV gastroenteritis (RVGE) outbreak occurred during the 2018/2019 season in Aichi prefecture, Japan. Therefore, the molecular epidemiology of RV among three different groups of RVGE, which were outpatients who received RV1, those who received RV5, and those without vaccination, was explored. Clinical features of RVGE patients were compared among the three patient groups. Children less than 15 years of age with gastroenteritis who visited any of seven pediatric practices between January and June 2019 were enrolled in the study. G, P, and E genotypes were determined by direct sequencing of reverse transcription-polymerase chain reaction products amplified from stool samples. Among 110 patients, there were 27, 28, and 55 in the RV1-vaccinated, RV5-vaccinated, and unvaccinated groups, respectively. The most frequent genotype was G8P[8] (92/110 patients, 83.6%). Genotype distributions did not significantly differ among the three patient groups (P = .125). Mean Vesikari score was significantly lower among RV1-vaccinated (7.1) and RV5-vaccinated patients (6.4) than among unvaccinated patients (10.2) (P < .001). Even in RVGE patients treated in an outpatient clinic, RV vaccine reduced the severity of the disease in this cohort.

Genetic heterogeneity of group A rotaviruses: a review of the evolutionary dynamics and implication on vaccination

INTRODUCTION

Human rotavirus remains a major etiology of acute gastroenteritis among under 5-year children worldwide despite the availability of oral vaccines. The genetic instability of rotavirus and the ability to form different combinations from the different G- and P-types reshapes the antigenic landscape of emerging strains which often display limited or no antigen identities with the vaccine strain. As evidence also suggests, the selection of the antigenically distinct novel or rare strains and their successful spread in the human population has raised concerns regarding undermining the effectiveness of vaccination programs.

AREAS COVERED

We review aspects related to current knowledge about genetic and antigenic heterogeneity of rotavirus, the mechanism of genetic diversity and evolution, and the implication of genetic change on vaccination.

EXPERT OPINION

Genetic changes in the segmented genome of rotavirus can alter the antigenic landscape on the virion capsid and further promote viral fitness in a fully vaccinated population. Against this background, the potential risk of the appearance of new rotavirus strains over the long term would be better predicted by a continued and increased close monitoring of the variants across the globe to identify any change associated with disease dynamics.

Rotavirus epidemiology and genotype distribution in hospitalised children, Greece, 2008 to 2020: A prospective multicentre study

BackgroundTwo rotavirus (RV) vaccines were licensed in Greece in late 2006 and included in the national immunisation programme in 2012.AimTo study the epidemiology and genotype distribution of RV in children during the post-vaccination period and assess the impact of increased vaccination coverage.MethodsIn a prospective multicentre hospital-based study, hospitalised children (≤ 16 years) with an RV-positive faecal sample were recruited. Epidemiological and genotyping analyses were performed; periods of low (2008-12) and moderate (2012-20) RV vaccination coverage were compared. Statistical analysis was performed with a chi-squared or Mann-Whitney U test and logistic regression.ResultsA total of 3,874 children (55.6% male; n = 2,153) with median age of 1.4 years (IQR: 0.5-3.3) were studied during 2008-20. Most RV-infected children were aged ≤ 3 years (72.2%) and hospitalised during December-May (69.1%). Common RV genotypes (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], G12P[8]) were detected in 92.2% of samples; G-P combinations with prevalence above 1% were G4P[8] (44.1%), G1P[8] (25.4%), G2P[4] (14.9%), G9P[8] (3.5%), G12P[8] (2.2%), G3P[8] (2.1%), other (4.3%) and mixed (3.5%). Of all samples, 97.6% were homotypic or partially heterotypic to vaccines' genotypes. With moderate vaccination coverage, the seasonal peak was detected earlier, children were older and partially or fully heterotypic genotypes were increased (p < 0.001).ConclusionsIn the era of moderate RV vaccination coverage in Greece, epidemiology of RV in hospitalised children seemed to change. However, most circulating genotypes remain homotypic or partially heterotypic to RV vaccines. Continuous epidemiological surveillance and genotyping are important to monitor possible changes arising from RV vaccines' implementation.

Rotavirus epidemiology and genotype distribution in hospitalised children, Greece, 2008 to 2020: A prospective multicentre study

BackgroundTwo rotavirus (RV) vaccines were licensed in Greece in late 2006 and included in the national immunisation programme in 2012.AimTo study the epidemiology and genotype distribution of RV in children during the post-vaccination period and assess the impact of increased vaccination coverage.MethodsIn a prospective multicentre hospital-based study, hospitalised children (≤ 16 years) with an RV-positive faecal sample were recruited. Epidemiological and genotyping analyses were performed; periods of low (2008-12) and moderate (2012-20) RV vaccination coverage were compared. Statistical analysis was performed with a chi-squared or Mann-Whitney U test and logistic regression.ResultsA total of 3,874 children (55.6% male; n = 2,153) with median age of 1.4 years (IQR: 0.5-3.3) were studied during 2008-20. Most RV-infected children were aged ≤ 3 years (72.2%) and hospitalised during December-May (69.1%). Common RV genotypes (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], G12P[8]) were detected in 92.2% of samples; G-P combinations with prevalence above 1% were G4P[8] (44.1%), G1P[8] (25.4%), G2P[4] (14.9%), G9P[8] (3.5%), G12P[8] (2.2%), G3P[8] (2.1%), other (4.3%) and mixed (3.5%). Of all samples, 97.6% were homotypic or partially heterotypic to vaccines' genotypes. With moderate vaccination coverage, the seasonal peak was detected earlier, children were older and partially or fully heterotypic genotypes were increased (p < 0.001).ConclusionsIn the era of moderate RV vaccination coverage in Greece, epidemiology of RV in hospitalised children seemed to change. However, most circulating genotypes remain homotypic or partially heterotypic to RV vaccines. Continuous epidemiological surveillance and genotyping are important to monitor possible changes arising from RV vaccines' implementation.

Characterization of Rotavirus Infection in Hospitalized Children under 5 with Acute Gastroenteritis 5 Years after Introducing the Rotavirus Vaccines in South Korea

We herein characterized rotavirus infection in hospitalized children under 5 years of age with gastroenteritis after introducing rotavirus vaccines in South Korea from 20 February 2012, to 31 March 2013. Enzyme-linked fluorescent immunoassay was performed to detect rotavirus antigens. G and P genotyping was performed using nested multiplex PCR. For the failed PCR samples, sequencing was conducted. We performed a test-negative case-control study to estimate vaccine effectiveness. Vaccine effectiveness was measured using a multivariate logistic regression model. Rotavirus was detected in 16 (13.2%) of the 121 patients, with a seasonal peak in April 2012. The dominant genotypes detected were G3P[8] (33.3%) and G4P[6] (26.7%), and vaccine effectiveness against rotavirus hospitalization was 84.9% [95% CI: 23.2−97.0] in the complete vaccinated group. A higher prevalence of rotavirus infection was observed among children with siblings than those without siblings (p < 0.001). Also, the presence of siblings was significantly associated with a history of nonvaccination (p < 0.001). In conclusion, the prevalence of rotavirus followed a decreasing trend, and there was no evidence of emergences of nonvaccine-type strains. Vaccine effectiveness against rotavirus hospitalization was 84.9%. Although children with siblings were more susceptible to rotavirus infection, they were less likely to receive vaccination against rotavirus.

Maintaining Momentum for Rotavirus Immunization in Africa during the COVID-19 Era: Report of the 13th African Rotavirus Symposium

The 13th African Rotavirus Symposium was held as a virtual event hosted by the University of Nairobi, Kenya and The Kenya Paediatric Association on 3rd and 4th November 2021. This biennial event organized under the auspices of the African Rotavirus Network shapes the agenda for rotavirus research and prevention on the continent, attracting key international and regional opinion leaders, researchers, and public health scientists. The African Rotavirus Network is a regional network of institutions initially established in 1999, and now encompassing much of the diarrheal disease and rotavirus related research in Africa, in collaboration with the World Health Organization African Regional Office (WHO-AFRO), Ministries of Health, and other partners. Surges in SARS-CoV2 variants and concomitant travel restrictions limited the meeting to a webinar platform with invited scientific presentations and scientific presentations from selected abstracts. The scientific program covered updates on burden of diarrheal diseases including rotavirus, the genomic characterization of rotavirus strains pre- and post-rotavirus vaccine introduction, and data from clinical evaluation of new rotavirus vaccines in Africa. Finally, 42 of the 54 African countries have fully introduced rotavirus vaccination at the time of the meeting, including the two recently WHO pre-qualified vaccines from India. Nonetheless, the full benefit of rotavirus vaccination is yet to be realized in Africa where approximately 80% of the global burden of rotavirus mortality exists.

Human rotavirus VP4 and VP7 genetic diversity and detection of GII norovirus in Ibadan as Nigeria introduces rotavirus vaccine

Objective

This cross-sectional study investigated the circulating strains of rotavirus and screened for noravirus in Ibadan, Nigeria as the country introduces the rotavirus vaccine into its national immunization program.

Methods

Sixty-five stool samples were collected from children younger than 5 years with clinically diagnosed diarrhea and screened for the presence of rotavirus and norovirus using RT-PCR. Rotavirus-positive samples were further analyzed to determine the G and P genotypes using semi-nested multiplex PCR.

Results

The rates of rotavirus and norovirus positivity were 30.8% and 10.8%, respectively, whereas the rate of rotavirus and norovirus mixed infection was 4.6%. G1 was the predominant VP7 genotype, followed by G2, G9, and G1G2G9, whereas the predominant VP4 genotype was P[4], followed by P[6], P[8], and P[9]. The mixed P types P[4]P[8] and P[4]P[6] were also detected. G1P[4] was the most common VP4 and VP7 combination, followed by G2P[4], G1[P6], G1P[8], G2P[6], G2P[9], G9P[6], G2G9P[4], G2P[4]P[6], G1P[4]P[8], G2G9P[8], G1G2G9P[8], and G1[non-typable] P[non-typable], which were detected in at least 5% of the samples. Four samples had a combination of non-typable G and P types.

Conclusions

It is essential to monitor the circulation of virus strains prior to and during the implementation of the immunization program.

Impact and effectiveness of monovalent rotavirus vaccine in Tajik children

BACKGROUND

In 2015, Tajikistan became the second country in Central Asia to introduce rotavirus vaccine into its national immunization program. Before vaccine introduction, rotavirus was estimated to cause > 40% of pediatric diarrhea hospitalizations in Tajikistan. We aimed to assess the impact of rotavirus vaccine introduction on rotavirus disease burden and estimate rotavirus vaccine effectiveness (VE).

METHODS

Using surveillance data from 2013 through 2019, we examined trends in monthly hospital admissions among children < 5 years old, before and after rotavirus vaccine introduction. Poisson regression was used to quantify decreases. VE was estimated using a test-negative case control design, with data from admissions during 2017 - 2019. Immunization records were obtained from clinics.

RESULTS

Among enrolled children, rotavirus positivity declined from 42% to 25% in the post-vaccine introduction period, a decrease of 41% (95% Confidence Interval [CI]: 36 - 45%). Declines were greatest in children < 12 months of age. Estimated VE of a complete course of rotavirus vaccine was 55% (95% CI: 21 - 73%) among children 5 - 59 months of age and 64% (95% CI: 36 - 80%) among children 5 - 23 months of age. VE point estimates were higher among children receiving both doses of rotavirus vaccine non-concurrently with OPV and among children receiving their first dose of rotavirus vaccine at 4 - 11 months of age, but CIs were wide and overlapping.

CONCLUSIONS

Our data demonstrate that rotavirus vaccine introduction was associated with a substantial reduction in pediatric rotavirus hospitalization burden in Tajikistan, and that rotavirus vaccination is effective in Tajik children.

Rotavirus Infection in Children <5 Years of Age in Suzhou, China, 2013-2019: Disease Burden, Genotype Distribution and Seasonality

BACKGROUND

This study aimed to determine the disease burden and strain distribution of rotavirus in children with diarrhea <5 years old in Suzhou, China.

METHODS

The study was conducted among children with diarrhea <5 years old at Suzhou University Affiliated Children's Hospital from 2013 to 2019. Rotavirus antigen was detected in clinical laboratory and then sent to Suzhou Centers for Disease Control and Prevention for further molecular analysis. Group A rotavirus (RVA) was detected through enzyme-linked immunosorbent assays, and G-genotype and P-genotype of RVA were tested using reverse transcription-polymerase chain reaction.

RESULTS

Of a total of 198,130 children with diarrhea, 70,813 (35.7%) were positive for RVA; RVA-related diarrhea was detected in 7798 (20.7%, n = 7798/37,710) inpatients and 63,015 (39.3%, n = 63,015/160,420) outpatients. Most children (92.0%, n = 65,171/70,813) positive for RVA were found as children <3 years old. Children 12-35 months old were reported as the highest prevalence among all age groups. The seasonal peak of RVA was in the autumn and winter. Among all 673 RVA strains genotyped, the G9P[8] strain was reported to be persistently predominant in the pediatric population from 2013 to 2019.

CONCLUSIONS

The burden of diarrhea disease due to rotavirus infection remains high in Suzhou.

Genotype Distribution and Evolutionary Analysis of Rotavirus Associated with Acute Diarrhea Outpatients in Hubei, China, 2013–2016

Group A human rotaviruses (RVAs) annually cause the deaths of 215,000 infants and young children. To understand the epidemiological characteristics and genetic evolution of RVAs, we performed sentinel surveillance on RVA prevalence in a rotavirus-surveillance network in Hubei, China. From 2013 to 2016, a total of 2007 fecal samples from hospital outpatients with acute gastroenteritis were collected from four cities of Hubei Province. Of the 2007 samples, 153 (7.62%) were identified positive for RVA by real-time RT-PCR. RVA infection in Hubei mainly occurred in autumn and winter. The highest detection rate of RVA infection was in 1–2 years old of outpatients (16.97%). No significant difference of RVA positive rate was observed between females and males. We performed a phylogenetic analysis of the G/P genotypes based on the partial VP7/VP4 gene sequences of RVAs. G9P[8] was the most predominant strain in all four years but the prevalence of G2P[4] genotype increased rapidly since 2014. We reconstructed the evolutionary time scale of RVAs in Hubei, and found that the evolutionary rates of the G9, G2, P[8], and P[4] genotypes of RVA were 1.069 ​× ​10⁻³, 1.029 ​× ​10⁻³, 1.283 ​× ​10⁻³ and 1.172 ​× ​10⁻³ nucleotide substitutions/site/year, respectively. Importantly, using a molecular clock model, we showed that most G9, G2, P[8], and P[4] genotype strains dated from the recent ancestor in 2005, 2005, 1993, and 2013, respectively. The finding of the distribution of RVAs in infants and young children in Hubei Province will contribute to the understanding of the epidemiological characteristics and genetic evolution of RVAs in China.

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A four-year study of sentinel surveillance program of RVAs was performed in Hubei, China.

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The key population of rotavirus infection is 1–2 years old of outpatients with acute gastroenteritis.

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G9P[8] was the most predominant strain between 2013 and 2016.

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The estimating time to the most recent common ancestor for the G9 genotype based on partial VP7 gene was 46 years.

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RVA distribution in Hubei Province contributes to the understanding of the epidemiological characteristics of RVAs in China.

Evolutionary changes between pre- and post-vaccine South African group A G2P[4] rotavirus strains, 2003-2017

The transient upsurge of G2P[4] group A rotavirus (RVA) after Rotarix vaccine introduction in several countries has been a matter of concern. To gain insight into the diversity and evolution of G2P[4] strains in South Africa pre- and post-RVA vaccination introduction, whole-genome sequencing was performed for RVA positive faecal specimens collected between 2003 and 2017 and samples previously sequenced were obtained from GenBank (n=103; 56 pre- and 47 post-vaccine). Pre-vaccine G2 sequences predominantly clustered within sub-lineage IVa-1. In contrast, post-vaccine G2 sequences clustered mainly within sub-lineage IVa-3, whereby a radical amino acid (AA) substitution, S15F, was observed between the two sub-lineages. Pre-vaccine P[4] sequences predominantly segregated within sub-lineage IVa while post-vaccine sequences clustered mostly within sub-lineage IVb, with a radical AA substitution R162G. Both S15F and R162G occurred outside recognised antigenic sites. The AA residue at position 15 is found within the signal sequence domain of Viral Protein 7 (VP7) involved in translocation of VP7 into endoplasmic reticulum during infection process. The 162 AA residue lies within the hemagglutination domain of Viral Protein 4 (VP4) engaged in interaction with sialic acid-containing structure during attachment to the target cell. Free energy change analysis on VP7 indicated accumulation of stable point mutations in both antigenic and non-antigenic regions. The segregation of South African G2P[4] strains into pre- and post-vaccination sub-lineages is likely due to erstwhile hypothesized stepwise lineage/sub-lineage evolution of G2P[4] strains rather than RVA vaccine introduction. Our findings reinforce the need for continuous whole-genome RVA surveillance and investigation of contribution of AA substitutions in understanding the dynamic G2P[4] epidemiology.

VP4 Is a Determinant of Alpha-Defensin Modulation of Rotaviral Infection

Fecal-oral pathogens encounter constitutively expressed enteric alpha-defensins in the intestine during replication and transmission. Alpha-defensins can be potently antiviral and antibacterial; however, their primary sequences, the number of isoforms, and their activity against specific microorganisms often vary greatly between species, reflecting adaptation to species-specific pathogens. Therefore, alpha-defensins might influence not only microbial evolution and tissue tropism within a host but also species tropism and zoonotic potential. To investigate these concepts, we generated a panel of enteric and myeloid alpha-defensins from humans, rhesus macaques, and mice and tested their activity against group A rotaviruses, an important enteric viral pathogen of humans and animals. Rotaviral adaptation to the rhesus macaque correlated with resistance to rhesus enteric, but not myeloid, alpha-defensins and sensitivity to human alpha-defensins. While mouse rotaviral infection was increased in the presence of mouse enteric alpha-defensins, two prominent genotypes of human rotaviruses were differentially sensitive to human enteric alpha-defensins. Furthermore, the effects of cross-species alpha-defensins on human and mouse rotaviruses did not follow an obvious pattern. Thus, exposure to alpha-defensins may have shaped the evolution of some, but not all, rotaviruses. We then used a genetic approach to identify the viral attachment and penetration protein, VP4, as a determinant of alpha-defensin sensitivity. Our results provide a foundation for future studies of the VP4-dependent mechanism of defensin neutralization, highlight the species-specific activities of alpha-defensins, and focus future efforts on a broader range of rotaviruses that differ in VP4 to uncover the potential for enteric alpha-defensins to influence species tropism. IMPORTANCE Rotavirus is a leading cause of severe diarrhea in young children. Like other fecal-oral pathogens, rotaviruses encounter abundant, constitutively expressed defensins in the small intestine. These peptides are a vital part of the vertebrate innate immune system. By investigating the impact that defensins from multiple species have on the infectivity of different strains of rotavirus, we show that some rotaviral infections can be inhibited by defensins. We also found that some, but not all, rotaviruses may have evolved resistance to defensins in the intestine of their host species, and some even appropriate defensins to increase their infectivity. Because rotaviruses infect a broad range of animals and rotaviral infections are highly prevalent in children, identifying immune defenses against infection and how they vary across species and among viral genotypes is important for our understanding of the evolution, transmission, and zoonotic potential of these viruses as well as the improvement of vaccines.

Rotavirus vaccines: progress and new developments

INTRODUCTION

Rotavirus is the primary cause of severe acute gastroenteritis among children under the age of five globally, leading to 128,500 to 215,000 vaccine-preventable deaths annually. There are six licensed oral, live-attenuated rotavirus vaccines: four vaccines pre-qualified for global use by WHO, and two country-specific vaccines. Expansion of rotavirus vaccines into national immunization programs worldwide has led to a 59% decrease in rotavirus hospitalizations and 36% decrease in diarrhea deaths due to rotavirus in vaccine-introducing countries.

AREAS COVERED

This review describes the current rotavirus vaccines in use, global coverage, vaccine efficacy from clinical trials, and vaccine effectiveness and impact from post-licensure evaluations. Vaccine safety, particularly as it relates to the risk of intussusception, is also summarized. Additionally, an overview of candidate vaccines in the pipeline is provided.

EXPERT OPINION

Considerable evidence over the past decade has demonstrated high effectiveness (80-90%) of rotavirus vaccines at preventing severe rotavirus disease in high-income countries, although the effectiveness has been lower (40-70%) in low-to-middle-income countries. Surveillance and research should continue to explore modifiable factors that influence vaccine effectiveness, strengthen data to better evaluate newer rotavirus vaccines, and aid in the development of future vaccines that can overcome the limitations of current vaccines.

Understanding Rotavirus Vaccine Efficacy and Effectiveness in Countries with High Child Mortality

Rotavirus claims thousands of lives of children globally every year with a disproportionately high burden in low- and lower-middle income countries where access to health care is limited. Oral, live-attenuated rotavirus vaccines have been evaluated in multiple settings in both low- and high-income populations and have been shown to be safe and efficacious. However, the vaccine efficacy observed in low-income settings with high rotavirus and diarrheal mortality was significantly lower than that seen in high-income populations where rotavirus mortality is less common. Rotavirus vaccines have been introduced and rolled out in more than 112 countries, providing the opportunity to assess effectiveness of the vaccines in these different settings. We provide an overview of the efficacy, effectiveness, and impact of rotavirus vaccines, focusing on high-mortality settings and identify the knowledge gaps for future research. Despite lower efficacy, rotavirus vaccines substantially reduce diarrheal disease and mortality and are cost-effective in countries with high burden. Continued evaluation of the effectiveness, impact, and cost-benefit of rotavirus vaccines, especially the new candidates that have been recently approved for global use, is a key factor for new vaccine introductions in countries, or for a switch of vaccine product in countries with limited resources.

Effect of rotavirus genetic diversity on vaccine impact

Group A rotaviruses (RVAs) are the leading cause of gastroenteritis, causing 0.2 million deaths and several million hospitalisations globally each year. Four rotavirus vaccines (Rotarix^TM , RotaTeq^TM , Rotavac^® and ROTASIIL^® ) have been pre-qualified by the World Health Organization (WHO), but the two newly pre-qualified vaccines (Rotavac^® and ROTASIIL^® ) are currently only in use in Palestine and India, respectively. In 2009, WHO strongly proposed that rotavirus vaccines be included in the routine vaccination schedule of all countries around the world. By the end of 2019, a total of 108 countries had administered rotavirus vaccines, and 10 countries have currently been approved by Gavi for the introduction of rotavirus vaccine in the near future. With 39% of global coverage, rotavirus vaccines have had a substantial effect on diarrhoeal morbidity and mortality in different geographical areas, although efficacy appears to be higher in high income settings. Due to the segmented RNA genome, the pattern of RVA genotypes in the human population is evolving through interspecies transmission and/or reassortment events for which the vaccine might be less effective in the future. However, despite the relative increase in some particular genotypes after rotavirus vaccine use, the overall efficacy of rotavirus mass vaccination worldwide has not been affected. Some of the challenges to improve the effect of current rotavirus vaccines can be solved in the future by new rotavirus vaccines and by vaccines currently in progress.

Rotavirus Vaccine Safety and Effectiveness in Infants With High-Risk Medical Conditions

OBJECTIVES

Rotavirus vaccination has 87% to 100% effectiveness against severe rotavirus acute gastroenteritis (AGE) in healthy infants in high-income countries. Little is known whether infants with medical risk conditions (MRCs) are equally protected and if the vaccine is equally well tolerated. We conducted a quasi-experimental prospective multicenter before-after cohort study to assess the vaccine effectiveness (VE) and safety profile of the human rotavirus vaccine (HRV) among MRC infants that required prolonged or frequent postnatal care.

METHODS

The Netherlands has no national rotavirus immunization program, but HRV was implemented in routine care for MRC infants in 13 Dutch hospitals. Participants in the before and after cohort, HRV unvaccinated and vaccinated, respectively, were followed for occurrence of (rotavirus) AGE. VE of at least 1 dose was estimated by using time-to-event analysis for severe rotavirus AGE. Vaccine-related serious adverse event (AEs) after HRV were retrieved systematically from medical charts. Solicited AEs after vaccinations were prospectively collected and compared between vaccination time points with or without HRV.

RESULTS

In total, 1482 high-risk infants with MRC were enrolled, including 631 in the before and 851 in the after cohorts; 1302 infants were premature (88.3%), 447 were small for gestational age (30.2%), and 251 had at least 1 congenital disorder (17.0%). VE against severe rotavirus AGE was 30% (95% confidence interval [CI]: -36% to 65%). Overall, the observed number of rotavirus hospitalizations was low and not significantly different between the cohorts (2 and 2, respectively). The rate of vaccine-related serious AE was 0.24 per 100 vaccine doses. The adjusted risk ratio for any AE after HRV vaccination compared with other routine vaccinations was 1.09 (95% CI: 1.05 to 1.12) for concomitant administration and 0.91 (95% CI: 0.81 to 0.99) for single HRV administration. Gastrointestinal AEs were 10% more frequent after HRV.

CONCLUSIONS

In contrast to previous findings among healthy term infants, in routine use, HRV offered limited protection to vulnerable medical risk infants. HRV is generally well tolerated in this group in single administration, but when coadministered with routine vaccines, it is associated with higher risk of (mostly gastrointestinal) AE. Our study highlights the importance of studying vaccine performance in subgroups of medically vulnerable infants.

Do Rotavirus Strains Affect Vaccine Effectiveness? A Systematic Review and Meta-analysis

BACKGROUND

Rotavirus causes 215,000 deaths from severe childhood diarrhea annually. Concerns exist that a monovalent vaccine (RV1) and a pentavalent vaccine (RV5) may be less effective against rotavirus strains not contained in the vaccines. We estimated the vaccine effectiveness (VE) of RV1 and RV5 against severe rotavirus gastroenteritis caused by vaccine (homotypic) and nonvaccine (partially and fully heterotypic) strains.

METHODS

After conducting a systematic review, we meta-analyzed 31 case-control studies (N = 27,293) conducted between 2006 and 2020 using a random-effects regression model.

RESULTS

In high-income countries, RV1 VE was 10% lower against partially heterotypic (P = 0.04) and fully heterotypic (P = 0.10) compared with homotypic strains (homotypic VE: 90% [95% confidence intervals (CI): 82-94]; partially heterotypic VE: 79% [95% CI: 71-85]; fully heterotypic VE: 80% [95% CI: 65-88]). In middle-income countries, RV1 VE was 14-16% lower against partially heterotypic (P = 0.06) and fully heterotypic (P = 0.04) compared with homotypic strains (homotypic VE: 81% [95% CI: 69-88]; partially heterotypic VE: 67% [95% CI: 54-76]; fully heterotypic VE: 65% [95% CI: 51-75]). Strain-specific RV5 VE differences were less pronounced, and primarily derived from high-income countries. Limited data were available from low-income countries.

CONCLUSIONS

Vaccine effectiveness of RV1 and RV5 was somewhat lower against nonvaccine than vaccine strains. Ongoing surveillance is important to continue long-term monitoring for strain replacement, particularly in low-income settings where data are limited.

A major decrease of viral acute gastroenteritis in hospitalized Finnish children as rotavirus returns as the most detected pathogen

INTRODUCTION

We assessed the prevalence and circulating genotypes of rotavirus, norovirus and sapovirus in children. The results were compared to previous surveillance studies from 2006-2008, 2009-2011 and 2012-2014 with similar methodology and setting, covering the start of universal vaccination with RotaTeq® in 2009.

METHODS

Stool samples were collected from children aged <16 years with acute gastroenteritis at Tampere University Hospital, Finland, from January 1^st, 2017 to December 31^st, 2018. The samples were analyzed using reverse transcription PCR and positive amplicons were sequenced.

RESULTS

A total of 178 stool samples were collected from 214 children. Rotavirus was detected in 56 (32 %), norovirus in 48 (27 %) and sapovirus in 11 (6.3 %) stool samples. Rotavirus G9P[8] and G12P[8] were the most detected genotypes in vaccinated and unvaccinated children. GII.4 comprised 96 % of the norovirus detections.

CONCLUSIONS

The prevalence of all-cause acute gastroenteritis in a hospital-setting has decreased by 51 % from 2012-2014, and by 88 % from 2006-2008. Rotavirus returns as the most common cause of viral acute gastroenteritis in children, but the prevalence remains at a low level. No considerable changes were seen in the genotyping results of norovirus and sapovirus.

Is the Rotavirus Vaccine Really Associated with a Decreased Risk of Developing Celiac and Other Autoimmune Diseases?

This review examines the risk of developing celiac disease (CD) and other autoimmune diseases in individuals receiving the rotavirus (RV) vaccine compared to the normal population. Celiac disease is a malabsorptive, chronic, immune-mediated enteropathy involving the small intestine. The pathogenesis of CD is multifactorial, and mucosal immunity plays an important role in its development. Low mucosal IgA levels significantly increase the risk of developing the disease. Rotavirus is an infectious agent that causes diarrhea, particularly in children aged 0-24 months, and is frequently involved in diarrhea-related deaths in these children. An oral vaccine against RV has been developed. While it is effective on RV infection, it also contributes to increasing mucosal immunity. Studies have indicated that individuals immunized with the RV vaccine are at lower risk of developing CD than unvaccinated individuals. In addition, the mean age for developing CD autoimmunity may be higher in the vaccinated group than in controls receiving placebo. Additional studies that include children immunized with different RV vaccines and unvaccinated children would provide more meaningful results. Although current data suggest a possible association of RV vaccination with a reduced risk of developing CD and other autoimmune diseases, this remains an unanswered question that merits greater international investigation.

Prevalence, Pattern and Genetic Diversity of Rotaviruses among Children under 5 Years of Age with Acute Gastroenteritis in South Africa: A Systematic Review and Meta-Analysis

Rotavirus is the most significant cause of severe acute gastroenteritis among children under 5 years of age, worldwide. Sub-Saharan Africa particularly bears the brunt of the diarrheal deaths. A meta-analysis was conducted on 43 eligible studies published between 1982 and 2020 to estimate the pooled prevalence of rotavirus infection and changes in the main rotavirus strains circulating before and after vaccine introduction among under-five children in South Africa. The pooled national prevalence of rotavirus infection was estimated at 24% (95% CI: 21-27%) for the pre-vaccination period and decreased to 23% (95% CI: 21-25%) in the post-vaccination period. However, an increased number of cases was observed in the KwaZulu-Natal (21-28%) and Western Cape (18-24%) regions post-vaccination. The most dominant genotype combinations in the pre-vaccine era was G1P[8], followed by G2P[4], G3P[8], and G1P[6]. After vaccine introduction, a greater genotype diversity was observed, with G9P[8] emerging as the predominant genotype combination, followed by G2P[4], G12P[8], and G1P[8]. The introduction of the rotavirus vaccine was associated with a reduction in the burden of rotavirus-associated diarrhea in South Africa, although not without regional fluctuation. The observed changing patterns of genotype distribution highlights the need for ongoing surveillance to monitor the disease trend and to identify any potential effects associated with the dynamics of genotype changes on vaccine pressure/failure.

Structural basis of P[II] rotavirus evolution and host ranges under selection of histo-blood group antigens

Group A rotaviruses cause severe gastroenteritis in infants and young children worldwide, with P[II] genogroup rotaviruses (RVs) responsible for >90% of global cases. RVs have diverse host ranges in different human and animal populations determined by host histo-blood group antigen (HBGA) receptor polymorphism, but details governing diversity, host ranges, and species barriers remain elusive. In this study, crystal structures of complexes of the major P[II] genogroup P[4] and P[8] genotype RV VP8* receptor-binding domains together with Lewis epitope-containing LNDFH I glycans in combination with VP8* receptor-glycan ligand affinity measurements based on NMR titration experiments revealed the structural basis for RV genotype-specific switching between ββ and βα HBGA receptor-binding sites that determine RV host ranges. The data support the hypothesis that P[II] RV evolution progressed from animals to humans under the selection of type 1 HBGAs guided by stepwise host synthesis of type 1 ABH and Lewis HBGAs. The results help explain disease burden, species barriers, epidemiology, and limited efficacy of current RV vaccines in developing countries. The structural data has the potential to impact the design of future vaccine strategies against RV gastroenteritis.

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.

Effectiveness of monovalent rotavirus vaccine against hospitalizations due to all rotavirus and equine-like G3P[8] genotypes in Haiti 2014-2019

BACKGROUND

Rotavirus vaccines are effective in preventing severe rotavirus. Haiti introduced 2-dose monovalent (G1P[8]) rotavirus vaccine recommended for infants at 6 and 10 weeks of age in 2014. We calculated the effectiveness of rotavirus vaccine against hospitalization for acute gastroenteritis in Haiti.

METHODS

We enrolled children 6-59 months old admitted May 2014-September 2019 for acute watery diarrhea at any sentinel surveillance hospital. Stool was tested for rotavirus using enzyme immunoassay (EIA) and genotyped with multiplex one-step RT-PCR assay and Sanger sequencing for stratification by genotype. We used a case-negative design where cases were children positive for rotavirus and controls were negative for rotavirus. Only children eligible for vaccination were included and a child was considered vaccinated if vaccine was given ≥ 14 days before enrollment. We used unconditional logistic regression to calculate odds ratios and calculated 2-dose and 1-dose vaccine effectiveness (VE) as (1 - odds ratio) * 100.

RESULTS

We included 129 (19%) positive cases and 543 (81%) negative controls. Among cases, 77 (60%) were positive for equine-like G3P[8]. Two doses of rotavirus vaccine were 66% (95% CI: 44, 80) effective against hospitalizations due to any strain of rotavirus and 64% (95% CI: 33, 81) effective against hospitalizations due to the equine-like G3P[8] genotype.

CONCLUSIONS

These findings are comparable to other countries in the Americas region. To the best of our knowledge, this is the first VE estimate both against the equine-like G3P[8] genotype and from a Caribbean country. Overall, these results support rotavirus vaccine use and demonstrate the importance of complete vaccination.

Association of Rotavirus Vaccines With Reduction in Rotavirus Gastroenteritis in Children Younger Than 5 Years: A Systematic Review and Meta-analysis of Randomized Clinical Trials and Observational Studies

IMPORTANCE

Rotavirus vaccines have been introduced worldwide, and the clinical association of different rotavirus vaccines with reduction in rotavirus gastroenteritis (RVGE) after introduction are noteworthy.

OBJECTIVE

To evaluate the comparative benefit, risk, and immunogenicity of different rotavirus vaccines by synthesizing randomized clinical trials (RCTs) and observational studies.

DATA SOURCES

Relevant studies published in 4 databases: Embase, PubMed, the Cochrane Library, and Web of Science were searched until July 1, 2020, using search terms including "rotavirus" and "vaccin*."

STUDY SELECTION

Randomized clinical trials and cohort and case-control studies involving more than 100 children younger than 5 years that reported the effectiveness, safety, or immunogenicity of rotavirus vaccines were included.

DATA EXTRACTION AND SYNTHESIS

A random-effects model was used to calculate relative risks (RRs), odds ratios (ORs), risk differences, and 95% CIs. Adjusted indirect treatment comparison was performed to assess the differences in the protection of Rotarix and RotaTeq.

MAIN OUTCOMES AND MEASURES

The primary outcomes were RVGE, severe RVGE, and RVGE hospitalization. Safety-associated outcomes involved serious adverse events, intussusception, and mortality.

RESULTS

A meta-analysis of 20 RCTs and 38 case-control studies revealed that Rotarix (RV1) significantly reduced RVGE (RR, 0.316 [95% CI, 0.224-0.345]) and RVGE hospitalization risk (OR, 0.347 [95% CI, 0.279-0.432]) among children fully vaccinated; RotaTeq (RV5) had similar outcomes (RVGE: RR, 0.350 [95% CI, 0.275-0.445]; RVGE hospitalization risk: OR, 0.272 [95% CI, 0.197-0.376]). Rotavirus vaccines also demonstrated higher protection against severe RVGE. Additionally, no significant differences in the protection of RV1 and RV5 against rotavirus disease were noted in adjusted indirect comparisons. Moderate associations were found between reduced RVGE risk and Rotavac (RR, 0.664 [95% CI, 0.548-0.804]), Rotasiil (RR, 0.705 [95% CI, 0.605-0.821]), and Lanzhou lamb rotavirus vaccine (RR, 0.407 [95% CI, 0.332-0.499]). All rotavirus vaccines demonstrated no risk of serious adverse events. A positive correlation was also found between immunogenicity and vaccine protection (eg, association of RVGE with RV1: coefficient, -1.599; adjusted R2, 99.7%).

CONCLUSIONS AND RELEVANCE

The high protection and low risk of serious adverse events for rotavirus vaccines in children who were fully vaccinated emphasized the importance of worldwide introduction of rotavirus vaccination. Similar protection provided by Rotarix and RotaTeq relieves the pressure of vaccines selection for health care authorities.

Rotavirus vaccine efficacy up to 2 years of age and against diverse circulating rotavirus strains in Niger: Extended follow-up of a randomized controlled trial

BACKGROUND

Rotavirus vaccination is recommended in all countries to reduce the burden of diarrhea-related morbidity and mortality in children. In resource-limited settings, rotavirus vaccination in the national immunization program has important cost implications, and evidence for protection beyond the first year of life and against the evolving variety of rotavirus strains is important. We assessed the extended and strain-specific vaccine efficacy of a heat-stable, affordable oral rotavirus vaccine (Rotasiil, Serum Institute of India, Pune, India) against severe rotavirus gastroenteritis (SRVGE) among healthy infants in Niger.

METHODS AND FINDINGS

From August 2014 to November 2015, infants were randomized in a 1:1 ratio to receive 3 doses of Rotasiil or placebo at approximately 6, 10, and 14 weeks of age. Episodes of gastroenteritis were assessed through active and passive surveillance and graded using the Vesikari score. The primary endpoint was vaccine efficacy of 3 doses of vaccine versus placebo against a first episode of laboratory-confirmed SRVGE (Vesikari score ≥ 11) from 28 days after dose 3, as previously reported. At the time of the primary analysis, median age was 9.8 months. In the present paper, analyses of extended efficacy were undertaken for 3 periods (28 days after dose 3 to 1 year of age, 1 to 2 years of age, and the combined period 28 days after dose 3 to 2 years of age) and by individual rotavirus G type. Among the 3,508 infants included in the per-protocol efficacy analysis (mean age at first dose 6.5 weeks; 49% male), the vaccine provided significant protection against SRVGE through the first year of life (3.96 and 9.98 cases per 100 person-years for vaccine and placebo, respectively; vaccine efficacy 60.3%, 95% CI 43.6% to 72.1%) and over the entire efficacy follow-up period up to 2 years of age (2.13 and 4.69 cases per 100 person-years for vaccine and placebo, respectively; vaccine efficacy 54.7%, 95% CI 38.1% to 66.8%), but the difference was not statistically significant in the second year of life. Up to 2 years of age, rotavirus vaccination prevented 2.56 episodes of SRVGE per 100 child-years. Estimates of efficacy against SRVGE by individual rotavirus genotype were consistent with the overall protective efficacy. Study limitations include limited generalizability to settings with administration of oral polio virus due to low concomitant administration, limited power to assess vaccine efficacy in the second year of life owing to a low number of events among older children, potential bias due to censoring of placebo children at the time of study vaccine receipt, and suboptimal adapted severity scoring based on the Vesikari score, which was designed for use in settings with high parental literacy.

CONCLUSIONS

Rotasiil provided protection against SRVGE in infants through an extended follow-up period of approximately 2 years. Protection was significant in the first year of life, when the disease burden and risk of death are highest, and against a changing pattern of rotavirus strains during the 2-year efficacy period. Rotavirus vaccines that are safe, effective, and protective against multiple strains represent the best hope for preventing the severe consequences of rotavirus infection, especially in resource-limited settings, where access to care may be limited. Studies such as this provide valuable information for the planning of national immunization programs and future vaccine development.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02145000.

Rotavirus Strain Surveillance in Estonia After Introduction of Rotavirus Universal Mass Vaccination

BACKGROUND

Estonia implemented the rotavirus (RV) vaccine into its national immunization program in July 2014. We aimed to determine circulating RV genotypes and the clinical profile by genotypes from February 1, 2015, to August 30, 2016, among children 0-18 years hospitalized due to rotavirus gastroenteritis (RVGE).

METHODS

During an observational study in 7 Estonian hospitals, we determined the RV genotypes in stool samples of RVGE patients who met predetermined criteria. Shannon's diversity index (H´) and Simpson's index (D) was used to evaluate genotype diversity by season and age and to compare prevaccine period data (2007-2008) for children 0-4 years of age (n = 77) to corresponding data from the postvaccine period (2015-2016, n = 346). The Vesikari Clinical Severity Scoring System was used for clinical profile evaluation.

RESULTS

Stool samples of 479 RVGE patients were genotyped. Seventy-seven percent of RVGE infections were caused by G4P[8] (n = 150, 31%), G1P[8] (n = 100, 21%), G9P[8] (n = 79, 16%), G2P[4] (n = 23, 5%), G4P[4] (n = 17,  4%). The prevailing genotypes varied seasonally. Diversity increased during the postvaccine period among age groups 0-4: H´1.42 (95% CI: 1.2-1.7) in the prevaccine era versus 1.8 (95% CI: 1.7-2) in the postvaccine era (P = 0.008), and D 0.6 (95% CI: 0.5-0.7) versus 0.78 (0.75-0.80) (P = 0.01), respectively. The off-season period presented higher diversity compared with in-seasons. G2P[8], G1P[8], G4P[4], G9P[8], and G8P[8] presented with a different clinical profile compared with others.

CONCLUSION

Since the introduction of universal mass vaccination in Estonia, the circulating RV genotypes have changed compared with those reported in the prevaccine era. Our study adds to knowledge about RV genotype distribution in Europe and expected dynamics after RV universal mass vaccination and provides insight on the clinical profile of prevailing genotypes.

New approach of genetic characterization of group A rotaviruses by the nanopore sequencing method

Nanopore sequencing of virus genomes represented by segmented RNA (e.g. rotaviruses) requires the development of specific approaches. Due to the massive use of rotavirus vaccines, the relevance of monitoring the genetic diversity of circulating strains of group A rotaviruses (RVA) increased. The WHO recommended method of multiplex type-specific PCR does not allow genotyping of all clinically significant strains of RVA and identifying inter-strain differences within the genotype. We have described a new principle of amplification of RVA gene segments using six primers for reverse transcription and one universal primer for PCR for nanopore sequencing. The amplification of RVA genome was tested on clinical samples and three phylogenetically distant laboratory RVA strains, Wa (G1P[8]), DS-1 (G2P[4]) and 568 (G3P[3]). The developed protocol of sample preparation and nanopore sequencing allowed obtaining full-length sequences for gene segments of RVA, including the diagnostically significant segments 9 (VP7), 4 (VP4) and 6 (VP6) with high accuracy and coverage. The accuracy of sequencing of the rotavirus genome exceeded 99.5 %, and the genome coverage varied for different strains from 59.0 to 99.6 % (on average 86 %). The developed approach of nanopore sequencing of RVA genome could be a prospective tool for epidemiological studies and surveillance of rotavirus infection.

Rotavirus Diarrhea in Hospitalized Under-5 Children in Madhya Pradesh, India and the Prevalent Serotypes After Vaccine Introduction

OBJECTIVE

To report epidemiology of rotavirus gastroenteritis among under-five children hospitalized for acute diarrhea after the introduction of vaccine in Madhya Pradesh.

METHODS

Children hospitalized for diarrhea between August 2017 and December 2019 were recruited. Stool sample was collected and shipped to Christian Medical College (CMC), Vellore maintaining proper cold chain. Samples were then screened for rotavirus using enzyme immunoassay (EIA). The samples that were positive for rotavirus were further genotyped by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Of the 794 stool samples collected, 150 (18.8%) samples were positive for rotavirus. Highest positivity was seen in winter months and in children less than 2 y of age. G3P[8] was found to be the most prevalent serotype.

CONCLUSIONS

The study highlights lowering prevalence of rotavirus gastroenteritis in the authors' region post vaccine introduction. It also highlights the change in prevalent serotypes.

Rotavirus Gastroenteritis Hospitalizations Among Under-5 Children in Northern India

OBJECTIVE

To study epidemiological profile, prevalence, and molecular epidemiology of RVGE in hospitalized under-5 children at a tertiary care teaching rural hospital located in sub-Himalayan belt of Northern India.

METHODS

This was a hospital-based surveillance study done over 4 y (2016-2019) including under-5 children hospitalized with acute gastroenteritis (AGE). Demographic and clinical parameters were recorded in a pre-designed performa. After consent, stool samples were collected and sent to Christian Medical College (CMC), Vellore for RV screening by enzyme immunoassay (EIA). Each EIA-positive sample was further subjected to G and P typing using published methods.

RESULTS

Out of total 851 included children, rotavirus gastroenteritis (RVGE) was detected in 23.03% (196/851) cases by EIA. The highest incidence for RVGE-positive cases (40.43%) was observed in 2016 with gradual decline over next 3 y. Maximum cases of diarrhea were observed in 12-23 mo age group along with highest rotavirus detection. G3P[8] was most common genotype (46.94%) found, followed by G1P[8] (13.78%), G2P[4] (4.59%), G1P[6] (8.16%) and G9P[4] (3.57%). Mixed genotype was seen in 13.78% of total cases.

CONCLUSION

This study summarizes the changing trends in the epidemiology of RVGE in Northern India along with the major circulating genotypes postvaccine introduction.

Australian Rotavirus Surveillance Program: Annual Report, 2018

Abstract

This report, from the Australian Rotavirus Surveillance Program and collaborating laboratories Australia-wide, describes the rotavirus genotypes identified in children and adults with acute gastroenteritis during the period 1 January to 31 December 2018. During this period, 690 faecal specimens were referred for rotavirus G- and P- genotype analysis, including 607 samples that were confirmed as rotavirus positive. Of these, 457/607 were wild-type rotavirus strains and 150/607 were identified as rotavirus vaccine-like. Genotype analysis of the 457 wild-type rotavirus samples from both children and adults demonstrated that G3P[8] was the dominant genotype nationally, identified in 52% of samples, followed by G2P[4] (17%). The Australian National Immunisation Program, which previously included both RotaTeq and Rotarix vaccines, changed to Rotarix exclusively on 1 July 2017. Continuous surveillance is needed to identify if the change in vaccination schedule could affect rotavirus genotype distribution and diversity in Australia.