Multiple Introductions and Antigenic Mismatch with Vaccines May Contribute to Increased Predominance of G12P[8] Rotaviruses in the United States

Rotavirus A Infection Prevalence and Spatio-Temporal Genotype Shift among Under-Five Children in Amhara National Regional State, Ethiopia: A Multi-Center Cross-Sectional Study

Background: Globally, rotavirus (RV) A (RVA) is the most common cause of severe and sometimes fatal diarrhea in young children. It is also the major cause of acute gastroenteritis among children in Ethiopia. Currently, the WHO has prequalified four RVA vaccines for universal childhood immunization. Ethiopia introduced the monovalent Rotarix vaccine into its national immunization program in 2013. Since then, only a few studies on the burden and genotype distribution of RVA infection post-vaccine introduction have been conducted (mostly at sentinel surveillance sites). Therefore, this study aimed to assess RVA prevalence and genotype distribution among children under five years in Ethiopia (February 2021-December 2022). Methods: This multi-center hospital-based cross-sectional study involved 537 diarrheic children under-five years old. Rotavirus A detection was conducted using a one-step reverse-transcriptase polymerase chain reaction (RT-PCR). Genotyping was conducted by Sanger sequencing of the VP7 (complete) and VP4 (partial) genes. Descriptive analysis and Pearson's chi-squared test were carried out using SPSS version 29. Phylogenetic analysis with 1000 bootstrap replicates was performed using MEGA version 11 software. Statistical significance was set at p < 0.05 for all analyses. Results: The prevalence of RVA infection among diarrheic children was 17.5%. The most prevalent G-types identified were G3 (37%), the previously uncommon G12 (28%), and G1 (20%). The predominant P-types were P[8] (51%), P[6] (29%), and P[4] (14%). The three major G/P combinations observed were G3P[8] (32.8%), G12P[6] (28.4%), and G1P[8] (19.4%). Phylogenetic analysis revealed clustering of Ethiopian strains with the globally reported strains. Many strains exhibited amino acid differences in the VP4 (VP8* domain) and VP7 proteins compared to vaccine strains, potentially affecting virus neutralization. Conclusions: Despite the high RVA vaccination rate, the prevalence of RVA infection remains significant among diarrheic children in Ethiopia. There is an observable shift in circulating RVA genotypes from G1 to G3, alongside the emergence of unusual G/P genotype combinations such as G9P[4]. Many of these circulating RVA strains have shown amino acid substitutions that may allow for neutralization escape. Therefore, further studies are warranted to comprehend the emergence of these unusual RVA strains and the diverse factors influencing the vaccine's diminished effectiveness in developing countries.

Immunogenicity of a Rotavirus VP8* Multivalent Subunit Vaccine in Mice

Rotavirus remains a significant public health threat, especially in low-income countries, where it is the leading cause of severe acute childhood gastroenteritis, contributing to over 128,500 deaths annually. Although the introduction of the Rotarix and RotaTeq vaccines in 2006 marked a milestone in reducing mortality rates, approximately 83,158 preventable deaths persisted, showing ongoing challenges in vaccine accessibility and effectiveness. To address these issues, a novel subcutaneous vaccine formulation targeting multiple rotavirus genotypes has been developed. This vaccine consists of nine VP8* proteins from nine distinct rotavirus genotypes and sub-genotypes (P[4], P[6], P[8]LI, P[8]LIII, P[8]LIV, P[9], P[11], P[14], and P[25]) expressed in E. coli. Two groups of mice were immunized either with a single immunogen, the VP8* from the rotavirus Wa strain (P[8]LI), or with the nonavalent formulation. Preliminary results from mouse immunization studies showed promising outcomes, eliciting antibody responses against six of the nine immunogens. Notably, significantly higher antibody titers against VP8* P[8]LI were observed in the group immunized with the nonavalent vaccine compared to mice specifically immunized against this genotype alone. Overall, the development of parenteral vaccines targeting multiple rotavirus genotypes represents a promising strategy in mitigating the global burden of rotavirus-related morbidity and mortality, offering new avenues for disease prevention and control.

Driving forces of continuing evolution of rotaviruses

Rotaviruses are non-enveloped double-stranded RNA virus that causes acute diarrheal diseases in children (< 5 years). More than 90% of the global rotavirus infection in humans was caused by Rotavirus group A. Rotavirus infection has caused more than 200000 deaths annually and predominantly occurs in the low-income countries. Rotavirus evolution is indicated by the strain dynamics or the emergence of the unprecedented strain. The major factors that drive the rotavirus evolution include the genetic shift that is caused by the reassortment mechanism, either in the intra- or the inter-genogroup. However, other factors are also known to have an impact on rotavirus evolution. This review discusses the structure and types, epidemiology, and evolution of rotaviruses. This article also reviews other supplemental factors of rotavirus evolution, such as genetic reassortment, mutation rate, glycan specificity, vaccine introduction, the host immune responses, and antiviral drugs.

Human Rotaviruses of Multiple Genotypes Acquire Conserved VP4 Mutations during Serial Passage

Human rotaviruses exhibit limited tropism and replicate poorly in most cell lines. Attachment protein VP4 is a key rotavirus tropism determinant. Previous studies in which human rotaviruses were adapted to cultured cells identified mutations in VP4. However, most such studies were conducted using only a single human rotavirus genotype. In the current study, we serially passaged 50 human rotavirus clinical specimens representing five of the genotypes most frequently associated with severe human disease, each in triplicate, three to five times in primary monkey kidney cells then ten times in the MA104 monkey kidney cell line. From 13 of the 50 specimens, we obtained 25 rotavirus antigen-positive lineages representing all five genotypes, which tended to replicate more efficiently in MA104 cells at late versus early passage. We used Illumina next-generation sequencing and analysis to identify variants that arose during passage. In VP4, variants encoded 28 mutations that were conserved for all P[8] rotaviruses and 12 mutations that were conserved for all five genotypes. These findings suggest there may be a conserved mechanism of human rotavirus adaptation to MA104 cells. In the future, such a conserved adaptation mechanism could be exploited to study human rotavirus biology or efficiently manufacture vaccines.

Detection and diversity of gastrointestinal viruses in wastewater from Caracas, Venezuela, 2021-2022

Gastrointestinal viruses (GIV) are an important cause of childhood morbidity and mortality, particularly in developing countries. Their epidemiological impact in Venezuela during the COVID-19 pandemic remains unclear. GIV can also be detected in domestic sewage. Ninety-one wastewater samples from urban areas of Caracas collected over 12 months and concentrated by polyethylene-glycol-precipitation, were analyzed by multiplex reverse-transcription-PCR for rotavirus/calicivirus/astrovirus and enterovirus/klassevirus/cosavirus, and monoplex-PCR for adenovirus and Aichi virus. The overall frequency of virus detection was 46.2%, fluctuating over months, and peaking in the rainy season. Adenoviruses circulated throughout the year, especially type F41, and predominated (52.7%) over caliciviruses (29.1%) that peaked in the rainy months, rotaviruses (9.1%), cosaviruses (5.5%), astroviruses and enteroviruses (1.8%). Aichi-virus and klassevirus were absent. Rotavirus G9/G12, and P[4]/P[8]/P[14] predominated. The occurrence of GIV in wastewater reflects transmission within the population of Caracas and the persistence of a potential public health risk that needs to be adequately monitored.

Characterization of Rotavirus Strains Responsible for Breakthrough Diarrheal Diseases among Zambian Children Using Whole Genome Sequencing

The occurrence of rotavirus (RV) infection among vaccinated children in high-burden settings poses a threat to further disease burden reduction. Genetically altered viruses have the potential to evade both natural infection and vaccine-induced immune responses, leading to diarrheal diseases among vaccinated children. Studies characterizing RV strains responsible for breakthrough infections in resource-limited countries where RV-associated diarrheal diseases are endemic are limited. We aimed to characterize RV strains detected in fully vaccinated children residing in Zambia using next-generation sequencing. We conducted whole genome sequencing on Illumina MiSeq. Whole genome assembly was performed using Geneious Prime 2023.1.2. A total of 76 diarrheal stool specimens were screened for RV, and 4/76 (5.2%) were RV-positive. Whole genome analysis revealed RVA/Human-wt/ZMB/CIDRZ-RV2088/2020/G1P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2 and RVA/Human-wt/ZMB/CIDRZ-RV2106/2020/G12P[4]-I1-R2-C2-M2-A2-N1-T2-E1-H2 strains were mono and multiple reassortant (exchanged genes in bold) respectively, whilst RVA/Human-wt/ZMB/CIDRZ-RV2150/2020/G12P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 was a typical Wa-like strain. Comparison of VP7 and VP4 antigenic epitope of breakthrough strains and Rotarix strain revealed several amino acid differences. Variations in amino acids in antigenic epitope suggested they played a role in immune evasion of neutralizing antibodies elicited by vaccination. Findings from this study have the potential to inform national RV vaccination strategies and the design of highly efficacious universal RV vaccines.

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.

Genome analyses of species A rotavirus isolated from various mammalian hosts in Northern Ireland during 2013-2016

Rotavirus group A (RVA) is the most important cause of acute diarrhoea and severe dehydration in young mammals. Infection in livestock is associated with significant mortality and economic losses and, together with wildlife reservoirs, acts as a potential source of zoonotic transmission. Therefore, molecular surveillance of circulating RVA strains in animal species is necessary to assess the risks posed to humans and their livestock. An RVA molecular epidemiological surveillance study on clinically diseased livestock species revealed high prevalence in cattle and pigs (31 per cent and 18 per cent, respectively) with significant phylogenetic diversity including a novel and divergent ovine artiodactyl DS-1-like constellation G10-P[15]-I2-R2-C2-M2-A11-N2-T6-E2-H3. An RVA gene reassortment occurred in an RVA asymptomatic pig and identified as a G5-P[13] strain, and a non-structural protein (NSP)2 gene had intergenomically reassorted with a human RVA strain (reverse zoonosis) and possessed a novel NSP4 enterotoxin E9 which may relate to the asymptomatic RVA infection. Analysis of a novel sheep G10-P[15] strain viral protein 4 gene imparts a putative homologous intergenic and interspecies recombination event, subsequently creating the new P[15] divergent lineage. While surveillance across a wider range of wildlife and exotic species identified generally negative or low prevalence, a novel RVA interspecies transmission in a non-indigenous pudu deer (zoo origin) with the constellation of G6-P[11]12-R2-C2-M2-A3-N2-T6-E2-H3 was detected at a viral load of 11.1 log10 copies/gram. The detection of novel emerging strains, interspecies reassortment, interspecies infection, and recombination of RVA circulating in animal livestock and wildlife reservoirs is of paramount importance to the RVA epidemiology and evolution for the One Health approach and post-human vaccine introduction era where highly virulent animal RVA genotypes have the potential to be zoonotically transmitted.

Two dimensional (2D) materials and biomaterials for water desalination; structure, properties, and recent advances

BACKGROUND

An efficient solution to the global freshwater dilemma is desalination. MXene, Molybdenum Disulfide (MoS₂), Graphene Oxide, Hexagonal Boron Nitride, and Phosphorene are just a few examples of two-dimensional (2D) materials that have shown considerable promise in the development of 2D materials for water desalination. However, other promising materials for desalinating water are biomaterials. The benefits of bio-materials are their wide distribution, lack of toxicity, and superior capacity for water desalination.

METHODS

For the rational use of water and the advancement of sustainable development, it is of the utmost importance to research 2D-dimensional materials and biomaterials that are effective for water desalination. The scientific community has concentrated on wastewater remediation using bio-derived materials, such as nanocellulose, chitosan, bio-char, bark, and activated charcoal generated from plant sources, among the various endeavors to enhance access to clean water. Moreover, the 2D-materials and biomaterials may have ushered in a new age in the production of desalination materials and created a promising future.

RESULTS

The present review article focuses on and reviews the progress of 2D materials and biomaterials for water desalination. Their properties, surface, and structure, combined with water desalination applications, are highlighted. Further, the practicability and potential future directions of 2D materials and biomaterials are proposed. Thus, the current work provides information and discernments for developing novel 2D materials and biomaterials for wastewater desalination. Moreover, it aims to promote the contribution and advancement of materials for water desalination, fabrication, and industrial production.

Complete genome analyses of G12P[8] rotavirus strains from hospitalized children in Surabaya, Indonesia, 2017-2018

Rotavirus A (RVA) is a major viral cause of acute gastroenteritis (AGE) worldwide. G12 RVA strains have emerged globally since 2007. There has been no report of the whole genome sequences of G12 RVAs in Indonesia. We performed the complete genome analysis by the next-generation sequencing of five G12 strains from hospitalized children with AGE in Surabaya from 2017 to 2018. All five G12 strains were Wa-like strains (G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1) and were clustered into lineage-III of VP7 gene phylogenetic tree. STM430 sample was observed as a mixed-infection between G12 and G1 strains: G12/G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. A phylogenetic tree analysis revealed that all five Indonesian G12 strains (SOEP379, STM371, STM413, STM430, and STM433) were genetically close to each other in all 11 genome segments with 98.0%-100% nucleotide identities, except VP3 and NSP4 of STM430, suggesting that these strains have originated from a similar ancestral G12 RVA. The VP3 and NSP4 genome segments of STM430-G12P[8] were separated phylogenetically from those of the other four G12 strains, probably due to intra-genotype reassortment between the G12 and G1 Wa-like strains. The change from G12P[6] lineage-II in 2007 to G12P[8] lineage-III 2017-2018 suggests the evolution and diversity of G12 RVAs in Indonesia over the past approximately 10 years.

Full genotype constellations analysis of unusual DS-1-like G12P[6] and G6P[8] rotavirus strains detected in Brazil, 2019

Rotavirus A (RVA) is a major cause of acute gastroenteritis (AGE) in children worldwide. We report unusual RVA G12P[6] and G6P[8] strains isolated from fecal samples from Brazilian children hospitalized for AGE. The characterized RVA have genome segments backbone: G12-P[6]/ G6-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 of DS-1-like genogroup. Our study describes the first identification of G6P[8], a DS-1-like genogroup strain. Nucleotide analysis of VP7 and VP4 genes revealed that all G12 Brazilian strains clustered into the sub-lineages IIIB, mostly associated with P[6] lineage I. Additionally, our G6 lineage I strains were closely related to German G6 genotypes, bound with P[8] lineage III, differing from both vaccine strains. The comparative sequence analysis of our strains with vaccine strains revealed amino acid substitutions located in immunodominant regions of VP7 and VP4 proteins. Continuous monitoring of RVA genotypes is essential to evaluate the impact of vaccination on the dynamic nature of RVA evolution.

Rotavirus Strain Trends in United States, 2009-2016: Results from the National Rotavirus Strain Surveillance System (NRSSS)

Before the introduction of vaccines, group A rotaviruses (RVA) were the leading cause of acute gastroenteritis in children worldwide. The National Rotavirus Strain Surveillance System (NRSSS) was established in 1996 by the Centers for Disease Control and Prevention (CDC) to perform passive RVA surveillance in the USA. We report the distribution of RVA genotypes collected through NRSSS during the 2009-2016 RVA seasons and retrospectively examine the genotypes detected through the NRSSS since 1996. During the 2009-2016 RVA seasons, 2134 RVA-positive fecal specimens were sent to the CDC for analysis of the VP7 and VP4 genes by RT-PCR genotyping assays and sequencing. During 2009-2011, RVA genotype G3P[8] dominated, while G12P[8] was the dominant genotype during 2012-2016. Vaccine strains were detected in 1.7% of specimens and uncommon/unusual strains, including equine-like G3P[8] strains, were found in 1.9%. Phylogenetic analyses showed limited VP7 and VP4 sequence variation within the common genotypes with 1-3 alleles/lineages identified per genotype. A review of 20 years of NRSSS surveillance showed two changes in genotype dominance, from G1P[8] to G3P[8] and then G3P[8] to G12P[8]. A better understanding of the long-term effects of vaccine use on epidemiological and evolutionary dynamics of circulating RVA strains requires continued surveillance.

Whole genome analysis of rotavirus strains circulating in Benin before vaccine introduction, 2016-2018

Species A Rotaviruses (RVA) still play a major role in causing acute diarrhea in children under five years old worldwide. Currently, an 11-gene classification system is used to designate the full genotypic constellations of circulating strains. Viral proteins and non-structural proteins in the order VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5/6 are represented by the genotypes Gx-P[x]-Ix-Rx-Cx-Mx-Ax-Nx-Tx-Ex-Hx, respectively. In Benin, ROTAVAC® vaccine was introduced into the Expanded Programme on Immunization in December 2019. To monitor circulating RVA strains for changes that may affect vaccine performance, in-depth analysis of strains prior to vaccine introduction are needed. Here we report, the whole-gene characterization (11 ORFs) for 72 randomly selected RVA strains of common and unusual genotypes collected in Benin from the 2016-2018 seasons. The sequenced strains were 15 G1P[8], 20 G2P[4], 5 G9P[8], 14 G12P[8], 9 G3P[6], 2 G1P[6], 3 G2P[6], 2 G9P[4], 1 G12P[6], and 1 G1G9P[8]/P[4]. The study strains exhibited two genetic constellations designed as Wa-like G1/G9/G12-P[6]/P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 and DS-1-like G2/G3/G12-P[4]/P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Genotype G9P[4] strains possessed a DS-1-like genetic constellation with an E6 NSP4 gene, G9-P[4]-I2-R2-C2-M2-A2-N2-T2-E6-H2. The mixed genotype showed both Wa-like and DS-1-like profiles with a T6 NSP3 gene G1/G9P[8]/[4]-I1/I2-R1/R2-C1/C2-M1/M2-A1/A2-N1/N2-T1/T6-E1/E6-H1/H2. At the allelic level, the analysis of the Benin strains, reference strains (with known alleles), vaccine strains (with known alleles) identified 2-13 and 1-17 alleles for DS-1-like and Wa-like strains, respectively. Most of the study strains clustered into previously defined alleles, but we defined 3 new alleles for the VP7 (G3=1 new allele and G12=2 new alleles) and VP4 (P[4]=1 new allele and P[6]=2 new alleles) genes which formed the basis of the VP7 and VP4 gene clusters, respectively. For the remaining 9 genes, 0-6 new alleles were identified for both Wa-like and DS-1-like strains. This analysis of whole genome sequences of RVA strains circulating in Benin described genetic point mutations and reassortment events as well as novel alleles. Further detailed studies on these new alleles are needed and these data can also provide a baseline for studies on RVA in the post-vaccination period.

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.

Monoreassortant rotaviruses of multiple G types are differentially neutralized by sera from infants vaccinated with ROTARIX® and RotaTeq®

Rotavirus is a leading cause of pediatric diarrheal mortality. The rotavirus outer capsid consists of VP7 and VP4 proteins, which respectively determine viral G and P type and are primary targets of neutralizing antibodies. To elucidate VP7-specific neutralizing antibody responses, we engineered monoreassortant rotaviruses each containing a human VP7 segment from a sequenced clinical specimen or a vaccine strain in an identical genetic background. We quantified replication and neutralization of engineered viruses using sera from infants vaccinated with monovalent ROTARIX® or multivalent RotaTeq® vaccines. Immunization with RotaTeq® induced broader neutralizing antibody responses than ROTARIX®. Inclusion of a single dose of RotaTeq® in the schedule enhanced G-type neutralization breadth of vaccinated infant sera. Cell type-specific differences in infectivity, replication, and neutralization were detected for some monoreassortant viruses. These findings suggest that rotavirus VP7, independent of VP4, can contribute to cell tropism and the breadth of vaccine-elicited neutralizing antibody responses.

Infection status and circulating strains of rotaviruses in Chinese children younger than 5-years old from 2011 to 2018: systematic review and meta-analysis

To evaluate rotavirus (RV) disease burden and circulating strains of RV among Chinese children younger than 5-years old who had diarrhea from 2011 to 2018. PubMed, Web of Science, Embase, CNKI and WANFANG databases were systematically searched to identify studies that reported RV prevalence in mainland China. After data extraction, a fixed-effects model or a random-effects model was applied to estimate RV positivity and proportions of G and P types. Statistical analysis was conducted using R software. We initially reviewed 1323 studies, and identified 69 studies that were eligible. The overall proportion of RV gastroenteritis (RVGE) among children under 5-years old who presented with diarrhea and sought medical care was 34.0% (95% CI: 31.3, 36.8), and RV positivity was higher among inpatients (39.7%) than outpatients (23.9%). Western areas of China had the highest proportion of RVGE (42.7%), and RV positivity was highest for children who were 6 months-old to 2 years-old. The most prevalent G types were G3 (26.1%), G9 (17.5%), and G1 (12.8%), the most prevalent P type was P[8] (56.8%) and the most prevalent G-P combination was G9P[8] (20.9%). RV continues to be a main cause of acute gastroenteritis in Chinese children who are younger than 5 years old. Following the introduction of an RV vaccine in 2011, monitoring of the disease burden of RV diarrhea and circulating strains in China remain important for assessments of vaccine efficacy.

Novel antigen panel for modern broad-spectrum recombinant rotavirus A vaccine

Purpose

Recombinant rotavirus A vaccines are being developed as an alternative to existing live oral attenuated vaccines. One of the main problems in the production of such vaccines is the genetic diversity of the strains that are in circulation. The goal of this study was to create an antigen panel for modern broad-spectrum recombinant rotavirus A vaccine.

Materials and Methods

The antigens of rotavirus were cloned and expressed in Escherichia coli. Antigenic specificity was investigated by Western blot analysis, which was performed using commercial polyclonal antisera to several RVA strains. Phylogenetic analysis was based on the amino acid sequences of the VP8^* protein fragment of human RVA isolates representing genotypes P[4], P[6], and P[8].

Results

A universal panel of antigens was established, including consensus and conserved sequences of structural proteins VP8^*, VP5^*, and VP7, which are the main targets of neutralizing antibodies. For the first time, a consensus approach was used in the design of extended antigens based on VP8^* (genotypes P[4], P[6], and P[8]) and VP5^* (genotype P[8]) proteins' fragments. In addition, a gene coding the protein (ep-875) containing several copies of conserved short neutralizing epitopes of VP8^*, VP7, and VP5^* was created. Western blot analysis demonstrated that three synthetic VP8^*-based antigens were not recognized by commercial antiserum against rotavirus strains isolated more than 35 years ago, but the specific activity of the VP5^* and ep-875 antigens was confirmed. The problems of serological mismatch of vaccine strains and antigens with currently circulating strains are discussed.

Conclusion

Five antigens representing sequences of structural proteins belonging to different genotypes can be used in various combinations (from mono- to pentavalent mixtures) for the development of an effective broad-spectrum rotavirus vaccine.

Rotavirus vaccination in Japan: Efficacy and safety of vaccines, changes in genotype, and surveillance efforts

In Japan, a monovalent rotavirus vaccine (RV1) and a pentavalent rotavirus vaccine (RV5) were launched as voluntary vaccinations in November 2011 and July 2012, respectively. Rotavirus (RV) vaccine coverage in Japan increased from 30.0% in 2012 to 78.4% in 2019. The number of RV gastroenteritis hospitalizations decreased after 2014 in Japan, and is expected to decrease further following the introduction of RV vaccines into the national immunization program in October 2020. The incidence rates of intussusception (IS) among children aged <1 year were 102.8 and 94.0 per 100,000 person-years in the pre-vaccine (2007-2011) and post-vaccine (2012-September 2014) eras, respectively. IS incidence did not increase following RV vaccine introduction in Japan. The efficacy and safety of RV vaccination were both documented in Japan. To reduce the risk of IS following RV vaccination, it is important that children receive a first dose of RV vaccine at age <15 weeks, preferably at age 2 months. Some strains that have emerged since RV vaccine introduction, such as DS-1-like G1P[8], eG3, and G8P[8], have spread nationwide. These three emerging genotypes did not affect the severity of the RV infection. Continuous city-level surveillance, using analysis of all 11 RV genome segments, is necessary to elucidate the genetic characteristics of prevalent RV strains. These efforts would also clarify the influence of vaccination on genetic changes of RV strains and the emergence of new genotypes.

Comparative genomic analysis of genogroup 1 and genogroup 2 rotaviruses circulating in seven US cities, 2014-2016

For over a decade, the New Vaccine Surveillance Network (NVSN) has conducted active rotavirus (RVA) strain surveillance in the USA. The evolution of RVA in the post-vaccine introduction era and the possible effects of vaccine pressure on contemporary circulating strains in the USA are still under investigation. Here, we report the whole-gene characterization (eleven ORFs) for 157 RVA strains collected at seven NVSN sites during the 2014 through 2016 seasons. The sequenced strains included 52 G1P[8], 47 G12P[8], 18 G9P[8], 24 G2P[4], 5 G3P[6], as well as 7 vaccine strains, a single mixed strain (G9G12P[8]), and 3 less common strains. The majority of the single and mixed strains possessed a Wa-like backbone with consensus genotype constellation of G1/G3/G9/G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1, while the G2P[4], G3P[6], and G2P[8] strains displayed a DS-1-like genetic backbone with consensus constellation of G2/G3-P[4]/P[6]/P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Two intergenogroup reassortant G1P[8] strains were detected that appear to be progenies of reassortment events between Wa-like G1P[8] and DS-1-like G2P[4] strains. Two Rotarix^® vaccine (RV1) and two RV5 derived (vd) reassortant strains were detected. Phylogenetic and similarity matrices analysis revealed 2-11 sub-genotypic allelic clusters among the genes of Wa- and DS-1-like strains. Most study strains clustered into previously defined alleles. Amino acid (AA) substitutions occurring in the neutralization epitopes of the VP7 and VP4 proteins characterized in this study were mostly neutral in nature, suggesting that these RVA proteins were possibly under strong negative or purifying selection in order to maintain competent and actual functionality, but fourteen radical (AA changes that occur between groups) AA substitutions were noted that may allow RVA strains to gain a selective advantage through immune escape. The tracking of RVA strains at the sub-genotypic allele constellation level will enhance our understanding of RVA evolution under vaccine pressure, help identify possible mechanisms of immune escape, and provide valuable information for formulation of future RVA vaccines.

Exploring rotavirus proteome to identify potential B- and T-cell epitope using computational immunoinformatics

Rotavirus is the most common cause of acute gastroenteritis in infants and children worldwide. The functional correlation of B- and T-cells to long-lasting immunity against rotavirus infection in the literature is limited. In this work, a series of computational immuno-informatics approaches were applied and identified 28 linear B-cells, 26 conformational B-cell, 44 T_C cell and 40 T_H cell binding epitopes for structural and non-structural proteins of rotavirus. Further selection of putative B and T cell epitopes in the multi-epitope vaccine construct was carried out based on immunogenicity, conservancy, allergenicity and the helical content of predicted epitopes. An in-silico vaccine constructs was developed using an N-terminal adjuvant (RGD motif) followed by T_C and T_H cell epitopes and B-cell epitope with an appropriate linker. Multi-threading models of multi-epitope vaccine construct with B- and T-cell epitopes were generated and molecular dynamics simulation was performed to determine the stability of designed vaccine. Codon optimized multi-epitope vaccine antigens was expressed and affinity purified using the E. coli expression system. Further the T cell epitope presentation assay using the recombinant multi-epitope constructs and the T cell epitope predicted and identified in this study have not been investigated. Multi-epitope vaccine construct encompassing predicted B- and T-cell epitopes may help to generate long-term immune responses against rotavirus. The computational findings reported in this study may provide information in developing epitope-based vaccine and diagnostic assay for rotavirus-led diarrhea in children's.

Reverse Genetics Approach for Developing Rotavirus Vaccine Candidates Carrying VP4 and VP7 Genes Cloned from Clinical Isolates of Human Rotavirus

Species A rotaviruses (RVs) are a leading cause of severe acute gastroenteritis in infants and children younger than 5 years. Currently available RV vaccines were adapted from wild-type RV strains by serial passage of cultured cells or by reassortment between human and animal RV strains. These traditional methods require large-scale screening and genotyping to obtain vaccine candidates. Reverse genetics is a tractable, rapid, and reproducible approach to generating recombinant RV vaccine candidates carrying any VP4 and VP7 genes that provide selected antigenicity. Here, we developed a vaccine platform by generating recombinant RVs carrying VP4 (P[4] and P[8]), VP7 (G1, G2, G3, G8, and G9), and/or VP6 genes cloned from human RV clinical samples using the simian RV SA11 strain (G3P[2]) as a backbone. Neutralization assays using monoclonal antibodies and murine antisera revealed that recombinant VP4 and VP7 monoreassortant viruses exhibited altered antigenicity. However, replication of VP4 monoreassortant viruses was severely impaired. Generation of recombinant RVs harboring a chimeric VP4 protein for SA11 and human RV gene components revealed that the VP8* fragment was responsible for efficient infectivity of recombinant RVs. Although this system must be improved because the yield of vaccine viruses directly affects vaccine manufacturing costs, reverse genetics requires less time than traditional methods and enables rapid production of safe and effective vaccine candidates.IMPORTANCE Although vaccines have reduced global RV-associated hospitalization and mortality over the past decade, the multisegmented genome of RVs allows reassortment of VP4 and VP7 genes from different RV species and strains. The evolutionary dynamics of novel RV genotypes and their constellations have led to great genomic and antigenic diversity. The reverse genetics system is a powerful tool for manipulating RV genes, thereby controlling viral antigenicity, growth capacity, and pathogenicity. Here, we generated recombinant simian RVs (strain SA11) carrying heterologous VP4 and VP7 genes cloned from clinical isolates and showed that VP4- or VP7-substituted chimeric viruses can be used for antigenic characterization of RV outer capsid proteins and as improved seed viruses for vaccine production.

The origins of G12P[6] rotavirus strains detected in Lebanon

The G12 rotaviruses are an increasingly important cause of severe diarrhoea in infants and young children worldwide. Seven human G12P[6] rotavirus strains were detected in stool samples from children hospitalized with gastroenteritis in Lebanon during a 2011-2013 surveillance study. Complete genomes of these strains were sequenced using VirCapSeq-VERT, a capture-based high-throughput viral-sequencing method, and further characterized based on phylogenetic analyses with global RVA and vaccine strains. Based on the complete genomic analysis, all Lebanese G12 strains were found to have Wa-like genetic backbone G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. Phylogenetically, these strains fell into two clusters where one of them might have emerged from Southeast Asian strains and the second one seems to have a mixed backbone between North American and Southeast Asian strains. Further analysis of these strains revealed high antigenic variability compared to available vaccine strains. To our knowledge, this is the first report on the complete genome-based characterization of G12P[6] emerging in Lebanon. Additional studies will provide important insights into the evolutionary dynamics of G12 rotaviruses spreading in Asia.

Genomic analysis of group A rotavirus G12P[8] including a new Japanese strain revealed evidence for intergenotypic recombination in VP7 and VP4 genes

Group A rotavirus is a leading cause of severe acute gastroenteritis worldwide. In this study, the first complete coding sequences of 11 RNA segments of human group A rotavirus G12P[8] in Japan were determined by an unbiased viral metagenomics. Its genomic constellation (VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes) was identified as G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. When performing the genetic analysis, we discovered an intergenotypic recombination event in the pig group A rotavirus G12P[8] strain BUW-14-A008. The novel recombination was found between two different genotypes G12 and G3 in the VP7 gene, and P[8] and P[13] in the VP4 gene.

Multiple Introductions and Predominance of Rotavirus Group A Genotype G3P[8] in Kilifi, Coastal Kenya, 4 Years after Nationwide Vaccine Introduction

Globally, rotavirus group A (RVA) remains a major cause of severe childhood diarrhea, despite the use of vaccines in more than 100 countries. RVA sequencing for local outbreaks facilitates investigation into strain composition, origins, spread, and vaccine failure. In 2018, we collected 248 stool samples from children aged less than 13 years admitted with diarrheal illness to Kilifi County Hospital, coastal Kenya. Antigen screening detected RVA in 55 samples (22.2%). Of these, VP7 (G) and VP4 (P) segments were successfully sequenced in 48 (87.3%) and phylogenetic analysis based on the VP7 sequences identified seven genetic clusters with six different GP combinations: G3P[8], G1P[8], G2P[4], G2P[8], G9P[8] and G12P[8]. The G3P[8] strains predominated the season (n = 37, 67.2%) and comprised three distinct G3 genetic clusters that fell within Lineage I and IX (the latter also known as equine-like G3 Lineage). Both the two G3 lineages have been recently detected in several countries. Our study is the first to document African children infected with G3 Lineage IX. These data highlight the global nature of RVA transmission and the importance of increasing global rotavirus vaccine coverage.

Product review of the rotavirus vaccines ROTASIIL, ROTAVAC, and Rotavin-M1

Rotavirus is the leading cause of severe dehydrating gastroenteritis and death due to diarrhea among children under 5, causing over 180,000 under-5 deaths annually. Safe, effective rotavirus vaccines have been available for over a decade and are used in over 98 countries. In addition to the globally available, WHO-prequalified ROTARIX (GSK) and RotaTeq (Merck), several new rotavirus vaccines have attained national licensure - ROTAVAC (Bharat Biotech) and ROTASIIL (Serum Institute of India), licensed and manufactured in India and now WHO-prequalified, and Rotavin-M1 (PolyVac), licensed and manufactured in Vietnam. In this review, we summarize the available clinical trial and post-introduction evidence for these three new orally administered rotavirus vaccines. All three vaccines have demonstrated safety and efficacy against rotavirus diarrhea, although publicly available preclinical data are limited in some cases. This expanding product landscape presents a range of options to optimize immunization programs, and new presentations of each vaccine are currently under development.

Comparative Analysis of G1P[8] Rotaviruses Identified Prior to Vaccine Implementation in Pakistan With Rotarix™ and RotaTeq™ Vaccine Strains

Group A rotavirus (RVA) is the leading cause of severe childhood diarrhea globally, even with all effective interventions, particularly in developing countries. Among the diverse genotypes of RVA, G1P[8] is a common genotype that has continued to pervade around the world, including Pakistan. Two universally accepted rotavirus vaccines-Rotarix™ and RotaTeq™ contain the genotype G1P[8]. The current work was aimed at identifying differences between antigenic epitopes of Pakistan’s G1P[8] strains and those of the two licensed vaccines. We sequenced 6 G1P[8] rotavirus strains previously reported in Rawalpindi, Islamabad, Pakistan in 2015 and 2016 for their outer capsid genes (VP7 and VP4). Phylogenetic analysis was then conducted in order to classify their specific lineages and to detect their association with strains isolated throughout world. Compared with the Rotarix™ and RotaTeq™ vaccine strains (G1-lineage II, P[8]-lineage III), our study G1-lineage I, P[8]-lineage IV strains showed 3 and 5 variations in the VP7 epitopes, respectively, and 13 and 11 variations in the VP4 epitopes, respectively. The G1 lineage II strains showed no single amino acid change compared to Rotarix™ (lineage II), but exhibited changes at 2 positions compared to RotaTeq™ (lineage III). So, this has been proposed that these G1 strains exist in our natural setting, or that they may have been introduced in Pakistan from other countries of the world. The distinct P[8]-lineage IV (OP354-like) strains showed twelve and thirteen amino acid variations, with Rotarix™ and RotaTeq™ (lineages II and III) strains, respectively. Such findings have shown that the VP4-P[8] component of the G1P[8] strains circulating in Pakistan differs considerably from that of the vaccine viruses compared to that of the VP7-G1. To monitor the long-term effects of vaccines on the emergence of G1P[8] strains with different lineages, routine and successful monitoring of these strains will be crucial.

Surveillance of Human Rotavirus in Wuhan, China (2011-2019): Predominance of G9P[8] and Emergence of G12

Rotaviruses are a major etiologic agent of gastroenteritis in infants and young children worldwide. To learn the shift of genotypes and genetic characteristics of Rotavirus A (RVA) causing diarrhea in children and adults, a hospital-based surveillance of rotavirus was conducted in Wuhan, China from June 2011 through May 2019, and representative virus strains were phylogenetically analyzed. Among a total of 6733 stool specimens collected from both children and adults with acute gastroenteritis, RVA was detected in 25.5% (1125/4409) and 12.3% (285/2324) of specimens, respectively. G9P[⁸] was the most common genotype (74.5%), followed by G1P[⁸] (8.7%), G2P[⁴] (8.4%), and G3P[⁸] (7.3%), with G9P[⁸] increasing rapidly during the study period. The predominant genotype shifted from G1P[⁸] to G9P[⁸] in 2012-2013 epidemic season. G12P[⁶] strain RVA/Human-wt/CHN/Z2761/2019/G12P[⁶] was detected in April 2019 and assigned to G12-P[⁶]-I1-R1-C1-M1-A1-N1-T2-E1-H1 genotypes. Phylogenetic analysis revealed that VP7, VP4, VP6, VP3, NSP1, NSP2, and NSP5 genes of Z2761 clustered closely with those of Korean G12P[⁶] strain CAU_214, showing high nucleotide identities (98.0-98.8%). The NSP3 gene of Z2761 was closely related to those of G2P[⁴] and G12P[⁶] rotaviruses in Asia. All the eleven gene segments of Z2761 kept distance from those of cocirculating G9P[⁸], G1P[⁸], and G3P[⁸] strains detected in Wuhan during this study period. This is the first identification of G12 rotavirus in China. It is deduced that Z2761 is a reassortant having DS-1-like NSP3 gene in the background of G12P[⁶] rotavirus genetically close to CAU_214.

Rapid generation of rotavirus single-gene reassortants by means of eleven plasmid-only based reverse genetics

Reassortment is an important mechanism in the evolution of group A rotaviruses (RVAs), yielding viruses with novel genetic and phenotypic traits. The classical methods for generating RVA reassortants with the desired genetic combinations are laborious and time-consuming because of the screening and selection processes required to isolate a desired reassortant. Taking advantage of a recently developed RVA reverse genetics system based on just 11 cloned cDNAs encoding the RVA genome (11 plasmid-only system), we prepared a panel of simian SA11-L2 virus-based single-gene reassortants, each containing 1 segment derived from human KU virus of the G1P[8] genotype. It was shown that there was no gene-specific restriction of the reassortment potential. In addition to these 11 single-gene reassortants, a triple-gene reassortant with KU-derived core-encoding VP1–3 gene segments with the SA11-L2 genetic background, which make up a virion composed of the KU-based core, and SA11-L2-based intermediate and outer layers, could also be prepared with the 11 plasmid-only system. Finally, for possible clinical application of this system, we generated a series of VP7 reassortants representing all the major human RVA G genotypes (G1–4, G9 and G12) efficiently. The preparation of each of these single-gene reassortants was achieved within just 2 weeks. Our results demonstrate that the 11 plasmid-only system allows the rapid and reliable generation of RVA single-gene reassortants, which will be useful for basic research and clinical applications.

Overview of the Development, Impacts, and Challenges of Live-Attenuated Oral Rotavirus Vaccines

Safety, efficacy, and cost-effectiveness are paramount to vaccine development. Following the isolation of rotavirus particles in 1969 and its evidence as an aetiology of severe dehydrating diarrhoea in infants and young children worldwide, the quest to find not only an acceptable and reliable but cost-effective vaccine has continued until now. Four live-attenuated oral rotavirus vaccines (LAORoVs) (Rotarix^®, RotaTeq^®, Rotavac^®, and RotaSIIL^®) have been developed and licensed to be used against all forms of rotavirus-associated infection. The efficacy of these vaccines is more obvious in the high-income countries (HIC) compared with the low- to middle-income countries (LMICs); however, the impact is far exceeding in the low-income countries (LICs). Despite the rotavirus vaccine efficacy and effectiveness, more than 90 countries (mostly Asia, America, and Europe) are yet to implement any of these vaccines. Implementation of these vaccines has continued to suffer a setback in these countries due to the vaccine cost, policy, discharging of strategic preventive measures, and infrastructures. This review reappraises the impacts and effectiveness of the current live-attenuated oral rotavirus vaccines from many representative countries of the globe. It examines the problems associated with the low efficacy of these vaccines and the way forward. Lastly, forefront efforts put forward to develop initial procedures for oral rotavirus vaccines were examined and re-connected to today vaccines.

Group A Rotavirus Detection and Genotype Distribution before and after Introduction of a National Immunisation Programme in Ireland: 2015-2019

Immunisation against rotavirus infection was introduced into Ireland in December 2016. We report on the viruses causing gastroenteritis before (2015–2016) and after (2017–2019) implementation of the Rotarix vaccine, as well as changes in the diversity of circulating rotavirus genotypes. Samples from patients aged ≤ 5 years (n = 11,800) were received at the National Virus Reference Laboratory, Dublin, and tested by real-time RT-PCR for rotavirus, Rotarix, norovirus, sapovirus, astrovirus, and enteric adenovirus. Rotavirus genotyping was performed either by multiplex or hemi-nested RT-PCR, and a subset was characterised by sequence analysis. Rotavirus detection decreased by 91% in children aged 0–12 months between 2015/16 and 2018/19. Rotarix was detected in 10% of those eligible for the vaccine and was not found in those aged >7 months. Rotavirus typically peaks in March–May, but following vaccination, the seasonality became less defined. In 2015–16, G1P[8] was the most common genotype circulating; however, in 2019 G2P[4] was detected more often. Following the introduction of Rotarix, a reduction in numbers of rotavirus infections occurred, coinciding with an increase in genotype diversity, along with the first recorded detection of an equine-like G3 strain in Ireland.

Group A rotavirus surveillance before vaccine introduction in Italy, September 2014 to August 2017

Introduction

Group A rotaviruses (RVA) are the leading cause of acute gastroenteritis (AGE) in young children, causing ca 250,000 deaths worldwide, mainly in low-income countries. Two proteins, VP7 (glycoprotein, G genotype) and VP4 (protease-sensitive protein, P genotype), are the basis for the binary RVA nomenclature. Although 36 G types and 51 P types are presently known, most RVA infections in humans worldwide are related to five G/P combinations: G1P[8], G2P[4], G3P[8], G4P[8], G9P[8].

Aim

This study aimed to characterise the RVA strains circulating in Italy in the pre-vaccination era, to define the trends of circulation of genotypes in the Italian paediatric population.

Methods

Between September 2014 and August 2017, after routine screening in hospital by commercial antigen detection kit, 2,202 rotavirus-positive samples were collected in Italy from children hospitalised with AGE; the viruses were genotyped following standard European protocols.

Results

This 3-year study revealed an overall predominance of the G12P[8] genotype (544 of 2,202 cases; 24.70%), followed by G9P[8] (535/2,202; 24.30%), G1P[8] (459/2,202; 20.84%) and G4P[8] (371/2,202; 16.85%). G2P[4] and G3P[8] genotypes were detected at low rates (3.32% and 3.09%, respectively). Mixed infections accounted for 6.49% of cases (143/2,202), uncommon RVA strains for 0.41% of cases (9/2,202).

Conclusions

The emergence of G12P[8] rotavirus in Italy, as in other countries, marks this genotype as the sixth most common human genotype. Continuous surveillance of RVA strains and monitoring of circulating genotypes are important for a better understanding of rotavirus evolution and genotype distribution, particularly regarding strains that may emerge from reassortment events.

Rotavirus symptomatic infection among unvaccinated and vaccinated children in Valencia, Spain

BACKGROUND

Human group A rotavirus is the leading cause of severe acute gastroenteritis in young children worldwide. Immunization programs have reduced the disease burden in many countries. Vaccination coverage in the Autonomous Region of Valencia, Spain, is around 40%, as the rotavirus vaccine is not funded by the National Health System. Despite this low-medium vaccine coverage, rotavirus vaccination has substantially reduced hospitalizations due to rotavirus infection and hospital-related costs. However, there are very few studies evaluating symptomatic rotavirus infections not requiring hospitalization in vaccinated children. The objective of this study was to investigate symptomatic rotavirus infections among vaccinated children in the health area served by the Hospital Clínico Universitario of Valencia, Spain, from 2013 to 2015.

METHODS

A total of 133 children younger than 5 years of age with rotavirus infection were studied. Demographic and epidemiological data were collected and informed consent from their caretakers obtained. Rotavirus infection was detected by immunological methods and G/P rotavirus genotypes were determined by RT-PCR, following standard procedures from the EuroRotaNet network.

RESULTS

Forty infants (30.1%; 95% CI: 22.3-37.9) out of 133 were diagnosed with symptomatic rotavirus infection despite having been previously vaccinated, either with RotaTeq (85%) or with Rotarix (15%). Children fully vaccinated against rotavirus (24.8%), partially vaccinated (5.3%) and unvaccinated (69.9%) were found. The infecting genotypes showed high G-type diversity, although no significant differences were found between the G/P genotypes infecting vaccinated and unvaccinated children during the same time period. G9P[8], G12P[8] and G1P[8] were the most prevalent genotypes. Severity of gastroenteritis symptoms required 28 (66.6%) vaccinated and 67 (73.6%) unvaccinated children to be attended at the Emergency Room.

CONCLUSION

Rotavirus vaccine efficacy in reducing the incidence of severe rotavirus infection has been well documented, but symptomatic rotavirus infection can sometimes occur in vaccinees.

Prevalence and molecular typing of rotavirus in children with acute diarrhoea in Northeastern Colombia

After the introduction of the rotavirus vaccine, the number of rotavirus-associated deaths and the predicted annual rotavirus detection rate had slightly declined worldwide. Taking in account that in Colombia, Rotarix vaccine was introduced in 2009, the purpose of this study was to evaluate the presence of rotavirus A in children under five years who were treated for acute diarrhoea in Bucaramanga, Colombia and, moreover, to determine the genotypes of rotavirus present in those children. We performed an analytical cross-sectional study of rotavirus A in faecal samples from children up to five years of age. Stool samples were screened for rotavirus A using a lateral-flow immunochromatographic assay and confirmed using a VP6 sandwich ELISA. Genotyping of rotavirus A-positive samples was performed by PCR and sequencing of VP7 and VP4 genes. The overall prevalence of rotavirus was 30.53% (95% confidence interval [CI] 21.2 - 39.7). Most of the children with rotavirus (86.2%) had received two doses of the rotavirus vaccine. G3 strains accounted for the vast majority of cases (82.8%), followed by G12 strains (13.8%) and G3/G9 coinfections (3.4%). Among the P genotypes, P[8] was the most prevalent (69%), followed by P[9] (31%). The most common G[P] genotype combination was G3P[8], followed by G3P[9]. The main finding in this study was that rotavirus, in a Colombian region, is still an important pathogen in children under five years old, previously vaccinated. The results showed that different factors, such as kindergarten attendance, could explain the epidemiology and transmission of rotavirus in Bucaramanga.

The 13th International Double-Stranded RNA Virus Symposium, Houffalize, Belgium, 24 to 28 September 2018

The triennial International Double-Stranded RNA Virus Symposium, this year organized by J. Matthijnssens, J. S. L. Parker, P. Danthi, and P. Van Damme in Belgium, gathered over 200 scientists to discuss novel observations and hypotheses in the field. The keynote lecture on functional interactions of bacteria and viruses in the gut microbiome was presented by Julie Pfeiffer. Workshops were held on viral diversity, molecular epidemiology, molecular virology, immunity and pathogenesis, virus structure, the viral use and abuse of cellular pathways, and applied double-stranded RNA (dsRNA) virology. The establishment of a plasmid only-based reverse genetics system for rotaviruses by several Japanese research groups in 2017 has now been reproduced by various other research groups and was discussed in detail. The visualization of dsRNA virus replication steps in living cells received much attention. Mechanisms of the cellular innate immune response to virus infection and of viral pathogenesis were explored. Knowledge of the gut microbiome's influence on specific immune responses has increased rapidly, also due to the availability of relevant animal models of virus infection. The method of cryo-electron microscopic (cryo-EM) tomography has elucidated various asymmetric structures in viral particles. The use of orthoreoviruses for oncolytic virotherapy was critically assessed. The application of llama-derived single chain nanobodies for passive immunotherapy was considered attractive. In a satellite symposium the introduction, impact and further developments of rotavirus vaccines were reviewed. The Jean Cohen Lecturer of this meeting was Harry B. Greenberg, who presented aspects of his research on rotaviruses over a period of more than 40 years. He was also interviewed at the meeting by Vincent Racaniello for the 513th session of This Week in Virology.