BACKGROUND: Using a multi-center, active surveillance network from two rotavirus seasons (2012 and 2013), we assessed the vaccine effectiveness of RV5 (RotaTeq) and RV1 (Rotarix) rotavirus vaccines in preventing rotavirus gastroenteritis hospitalizations and emergency department (ED) visits for numerous demographic and secular strata. METHODS: We enrolled children hospitalized or visiting the ED with acute gastroenteritis (AGE) for the 2012 and 2013 seasons at 7 medical institutions. Stool specimens were tested for rotavirus by enzyme immunoassay and genotyped, and rotavirus vaccination histories were compared for rotavirus-positive cases and rotavirus-negative AGE controls. We calculated the VE for preventing rotavirus associated hospitalizations and ED visits for each vaccine, stratified by vaccine dose, season, clinical setting, age, predominant genotype, and ethnicity. RESULTS: RV5-specific VE analyses included 2,961 subjects, 402 rotavirus cases (14%) and 2,559 rotavirus-negative AGE controls. RV1-specific VE analyses included 904 subjects, 100 rotavirus cases (11%) and 804 rotavirus-negative AGE controls. Over the two rotavirus seasons, the VE for a complete 3-dose vaccination with RV5 was 80% (CI= 74% - 84%), and VE for a complete 2-dose vaccination with RV1 was 80% (CI= 68% - 88%).Statistically significant VE was observed for each year of life for which sufficient data allowed analysis (7 years for RV5 and 3 years for RV1). Both vaccines provided statistically significant genotype-specific protection against predominant circulating rotavirus strains. CONCLUSION: In this large, geographically and demographically diverse sample of US children, we observed that RV5 and RV1 rotavirus vaccines each provided a lasting, and broadly heterologous protection against rotavirus gastroenteritis.

Rotarix vaccine was introduced into the National Program of Immunization of Morocco in October 2010, reaching quickly 87% of the target population of children nationally. The incidence of rotavirus gastroenteritis and the prevalence of circulating rotavirus strains has been monitored in three sentinel hospitals since June 2006. The average percentage of rotavirus positive cases among all children under 5 years old hospitalized for gastroenteritis during the pre-vaccine period (2006-2010) was 44%. This percentage dropped to 29%, 15% and 24% in the 3 years post vaccine introduction (2011, 2012 and 2013), which is a decline of 34%, 66%, and 45%, respectively. Declines in prevalence were greatest among children 0-1 years of age (53%) and were most prominent during the winter and autumn rotavirus season. The prevalence of the G2P[4] and G9P[8] genotype sharply increased in the post vaccine period (2011-2013) compared to the previous seasons (2006-2010). Rotavirus vaccines have reduced greatly the number of children hospitalized due to rotavirus infection at the three sentinel hospitals; it is however unclear if the predominance of G2P[4] and G9P[8] genotypes is related to the vaccine introduction, or if this is attributable to normal genotype fluctuations. Continued surveillance will be pivotal to answer this question in the future.

Group A rotaviruses (RVA) are double stranded RNA viruses that are a significant cause of acute pediatric gastroenteritis. Beginning in 2006 and 2008, respectively, two vaccines, Rotarix and RotaTeq(R), have been approved for use in the USA for prevention of RVA disease. The effects of possible vaccine pressure on currently circulating strains in the USA and their genome constellations are still under investigation. In this study we report 33 complete RVA genomes (ORF regions) collected in multiple cities across USA during 2006-2009, including 8 collected from children with verified receipt of 3 doses of rotavirus vaccine. The strains included 16 G1P[8], 10 G3P[8], and 7 G9P[8]. All 33 strains had a Wa like backbone with the consensus genotype constellation of G(1/3/9)-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. From maximum likelihood based phylogenetic analyses, we identified 3-7 allelic constellations grouped mostly by respective G types, suggesting a possible allelic segregation based on the VP7 gene of RVA primarily for the G3 and G9 strains. The vaccine failure strains showed similar grouping for all genes in G9 strains and most genes of G3 strains suggesting that these constellations were necessary to evade vaccine-derived immune protection. Substitutions in the antigenic region of VP7 and VP4 genes were also observed for the vaccine failure strains which could possibly explain how these strains escape vaccine induced immune response. This study helps elucidate how RVA strains are currently evolving in the population post vaccine introduction and supports the need for continued RVA surveillance.

Since 2004, the Pan American Health Organization (PAHO) has carried out rotavirus surveillance in Latin America and the Caribbean. Here we report the characterization of human rotavirus with the novel G-P combination of G4P[14], detected through PAHO surveillance in Barbados. Full genome sequencing of strain RVA/Human-wt/BRB/CDC1133/2012/G4P[14] revealed that its genotype is G4-P[14]-I1-R1-C1-M1-A8-N1-T1-E1-H1. The possession of a Genogroup 1 (Wa-like) backbone distinguishes this strain from other P[14] rotavirus strains. Phylogenetic analyses suggested that this strain was likely generated by genetic reassortment between human, porcine and possibly other animal rotavirus strains and identified 7 lineages within the P[14] genotype. The results of this study reinforce the potential role of interspecies transmission in generating human rotavirus diversity through reassortment. Continued surveillance is important to determine if rotavirus vaccines will protect against strains that express the P[14] rotavirus genotype.

This study describes group A rotavirus (RVA) genotype prevalence in Belarus from 2008 to 2012. In 2008, data from 3 sites in Belarus (Brest, Mogilev, Minsk) indicated that G4P[8] was the predominant genotype. Data from Minsk (2008-2012) showed that G4P[8] was the predominant RVA genotype in all years except in 2011 when G3P[8] was most frequently detected. Other RVA genotypes common in Europe (G1P[8], G2P[4]) were detected each year of the study. This study reveals the dominance of genotype G4P[8] in Belarus and helps to establish the baseline genotype prevalence prior to RVA vaccine introduction in the country.

Surveillance networks for rotavirus document the burden of the disease using the proportion of children hospitalized with gastroenteritis positive for rotavirus by enzyme immunoassay. They also describe genotypes of circulating viruses by polymerase chain reaction for the VP7 and VP4 genes, which determine G and P types, respectively. A proportion of samples cannot be genotyped based on initial testing and laboratories need to assess further testing strategies based on resources and feasibility. To 365 samples obtained from an Indian rotavirus strain surveillance program, we applied an approach to determine the G and P types in antigen positive samples that failed to type initially with the standard laboratory protocol. Fifty-eight samples (19%) were negative for the VP6 gene, indicating that the antigen test was likely to have been false positive. Alternative extraction and priming approaches resulted in the identification of G and P types for 264 strains. The identity of one strain was determined by sequencing the first-round amplicons. Thirty-five strains were partially typed and seven strains could not be typed at all. The distribution of G and P types among strains that had initially failed to type, except one strain, did not differ from that in strains that were typed using the standard laboratory protocol.

Since 2008, the World Health Organization (WHO) has coordinated the Global Rotavirus Surveillance Network, a network of sentinel surveillance hospitals and laboratories that report to ministries of health (MoHs) and WHO clinical features and rotavirus testing data for children aged <5 years hospitalized with acute gastroenteritis. In 2013, WHO conducted a strategic review to assess surveillance network performance, provide recommendations for strengthening the network, and assess the network's utility as a platform for other vaccine-preventable disease surveillance. The strategic review team determined that during 2011 and 2012, a total of 79 sites in 37 countries met reporting and testing inclusion criteria for data analysis. Of the 37 countries with sites meeting inclusion criteria, 13 (35%) had introduced rotavirus vaccine nationwide. All 79 sites included in the analysis were meeting 2008 network objectives of documenting presence of disease and describing disease epidemiology, and all countries were using the rotavirus surveillance data for vaccine introduction decisions, disease burden estimates, and advocacy; countries were in the process of assessing the use of this surveillance platform for other vaccine-preventable diseases. However, the review also indicated that the network would benefit from enhanced management, standardized data formats, linkage of clinical data with laboratory data, and additional resources to support network functions. In November 2013, WHO's Strategic Advisory Group of Experts on Immunization (SAGE) endorsed the findings and recommendations made by the review team and noted potential opportunities for using the network as a platform for other vaccine-preventable disease surveillance. WHO will work to implement the recommendations to improve the network's functions and to provide higher quality surveillance data for use in decisions related to vaccine introduction and vaccination program sustainability.

In 2006-07, 77 cases of gastroenteritis in Rochester, NY, USA were associated with rotavirus genotype G12P[8]. Sequence analysis identified a high degree of genetic relatedness among the VP7 and VP4 genes of the Rochester G12P[8] strains and between these strains and currently circulating human G12P[8] strains. Out of 77 samples, two and seven unique nucleotide sequences were identified for VP7 and VP4 genes, respectively. Rochester strain VP7 genes were found to occupy the G12-III lineage and VP4 genes clustered within the P[8]-3 lineage. Six strains contained non-synonymous nucleotide substitutions that produced amino acid changes at 6 sites in the VP8 * region of the VP4 gene. Two sites (amino acids 242 and 246) were located in or near a described trypsin cleavage site. Selection analyses identified one positively selected VP7 site (107) and strong purifying selection at 58 sites within the VP7 gene as well as 2 of the 6 variant sites (79 and 218) in VP4.

Group A rotaviruses (RVA) are the leading cause of severe diarrhea in young children worldwide. Two live-attenuated RVA vaccines, Rotarix(R) and RotaTeq(R) are recommended by World Health Organization (WHO) for routine immunization of all infants. Rotarix(R) and RotaTeq(R) vaccines have substantially reduced RVA associated mortality but occasionally have been associated with acute gastroenteritis (AGE) cases identified in vaccinees and their contacts. High-throughput assays are needed to monitor the prevalence of vaccine strains in AGE cases and emergence of new vaccine-derived strains following RVA vaccine introduction. In this study, we have developed quantitative real-time RT-PCR (qRT-PCR) assays for detection of Rotarix(R) and RotaTeq(R) vaccine components in stool samples. Real-time RT-PCR assays were designed for vaccine specific targets in the genomes of Rotarix(R) (NSP2, VP4) and RotaTeq(R) (VP6, VP3-WC3, VP3-human) and validated on sequence confirmed stool samples containing vaccine strains, wild-type RVA strains, and RVA-negative stools. For quantification, standard curves were generated using dsRNA transcripts derived from RVA gene segments. Rotarix(R) NSP2 and VP4 qRT-PCR assays exhibited 92-100% sensitivity, 99-100% specificity, 94-105% efficiency, and a limit of detection of 2-3 copies per reaction. RotaTeq(R) VP6, VP3-WC3, and VP3-human qRT-PCR assays displayed 100% sensitivity, 94-100% specificity, 91-102% efficiency and limits of detection of 1 copy, 2 copies, and 140 copies, respectively. These assays permit rapid identification of Rotarix(R) and RotaTeq(R) vaccine components in stool samples from clinical and surveillance studies and will be helpful in determining the frequency of vaccine strain-associated AGE.

BACKGROUND: In January of 2008, during the peak of the rotavirus season in Guatemala, a gastroenteritis outbreak with high mortality among infants was reported in Guatemala. Despite extensive efforts, the investigation was limited by the lack of bulk stool specimens collected, particularly from the more severely dehydrated or deceased children. OBJECTIVES: We evaluated the diagnostic performance of rectal swab specimens compared with bulk stool for the detection of rotavirus and norovirus. STUDY DESIGN: Patients with diarrhea (≥3 loose stools in 24h) were enrolled through an ongoing surveillance system in Guatemala. From January through March 2009, we attempted to enroll 100 patients <5 years old captured by the diarrhea surveillance, and collected paired bulk stool and rectal swabs specimens from them. Specimens were tested for norovirus using real-time reverse transcription-polymerase chain reaction and for rotavirus via enzyme immunoassay. RESULTS: We enrolled 102 patients with paired specimens; 91% of 100 paired specimens tested for rotavirus yielded concordant results positive for rotavirus with a negativity rate of 83%. Among 100 paired specimens tested for norovirus, 86% were concordant norovirus detection and the negativity rate was 85%. The diagnostic performance for rotavirus and norovirus detection did not differ significantly between the two specimen types. CONCLUSIONS: Testing of properly collected fecal specimens using rectal swabs may be a viable alternative to bulk stool for detection of rotavirus and norovirus, particularly during outbreaks where collection of bulk stool may be difficult.

Group A rotaviruses are the most common viral cause of acute gastroenteritis in young children. The most frequently detected group A rotavirus genotype combinations include G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8]. The G9 genotype has been associated with multiple P types, including P[8], P[6], and P[4], although genotype G9P[8] is predominant (1). | In Latin America, a large number of unusual G-P combinations have been reported, and among these is the rare G9P[4] genotype, which was identified in Brazil in the 1990s (2), and later reported infrequently elsewhere in Latin America (3). In 2010, cases of group A rotavirus gastroenteritis associated with genotype G9P[4] were reported in Mexico (4). Increases in the incidence of group A rotavirus gastroenteritis were reported in 2010 in Mexico and Guatemala and in 2009 in Honduras (http://new.paho.org/hq/dmdocuments/2010/Epi_Alerts_2010_mar_5_rotavirus.pdf). | In response to these reports of increased group A rotavirus disease, fecal samples collected in Chiapas State, Mexico (in 2010, 30% of the cases in Mexico were from Chiapas), Guatemala, and Honduras in 2009–2010 that were positive by enzyme immunoassay were sent to the US Centers for Disease Control and Prevention (Atlanta, GA, USA) for characterization. Viral protein 4 (VP4) (P) and VP7 (G) genotyping, nucleotide sequencing, and genotype identification were performed by using consensus and genotype-specific oligonucleotide primers (5), and sequences were subjected to phylogenetic analyses. VP6 and nonstructural protein 4 (NSP4) genes of selected samples were also sequenced.

A real-time reverse transcription-polymerase chain reaction (qRT-PCR) assay using the recombinant thermostable Thermus thermophilus (rTth) enzyme was developed to detect and quantify rotavirus A (RVA). By using rTth polymerase, significant improvement was achieved over the existing real-time RT-PCR assays which require denaturation of the RVA double-stranded RNA (dsRNA) prior to assay set-up. Using a dsRNA transcript for segment 7 which encodes the assay target NSP3 gene, the limit of detection for the improved assay was calculated to be approximately 1 genome copy per reaction. The NSP3 qRT-PCR assay was validated using a panel of 1906 stool samples, 23 reference RVA strains, and 14 non-target enteric virus samples. The assay detected a diverse number of RVA genotypes and did not detect other enteric viruses demonstrating analytical sensitivity and specificity for RVA when testing stool samples. A XenoRNA internal process control was introduced and detected in a multiplexed qRT-PCR format. Because it does not require an antecedent dsRNA denaturation step, this assay reduces the possibility of sample cross-contamination and requires less hands-on time than other published qRT-PCR protocols for RVA detection.

We compared rotavirus detection rates in children with acute gastroenteritis (AGE) and in healthy controls using enzyme immunoassays (EIAs) and semiquantitative real-time reverse transcription PCR (qRT-PCR). We calculated rotavirus vaccine effectiveness using different laboratory-based case definitions to determine which best identified the proportion of disease that was vaccine preventable. Of 648 AGE patients, 158 (24%) were EIA positive, and 157 were also qRT-PCR positive. An additional 65 (10%) were qRT-PCR positive but EIA negative. Of 500 healthy controls, 1 was EIA positive and 24 (5%) were qRT-PCR positive. Rotavirus vaccine was highly effective (84% [95% CI 71%-91%]) in EIA-positive children but offered no significant protection (14% [95% CI -105% to 64%]) in EIA-negative children for whom virus was detected by qRT-PCR alone. Children with rotavirus detected by qRT-PCR but not by EIA were not protected by vaccination, suggesting that rotavirus detected by qRT-PCR alone might not be causally associated with AGE in all patients.

Surveillance for rotavirus-associated diarrhea after implementation of rotavirus vaccination can assess vaccine effectiveness and identify disease-associated genotypes. During active vaccine postlicensure surveillance in the United States, we found a novel rotavirus genotype, G14P[24], in a stool sample from a child who had diarrhea. Unusual rotavirus strains may become more prevalent after vaccine implementation.

In this study the emergence of rotavirus A genotype G12 in children <5 years of age is reported from Cameroon during 2010/2011. A total of 135 human stool samples were P and G genotyped by reverse transcriptase PCR. Six different rotavirus VP7 genotypes were detected, including G1, G2, G3, G8, G9, and G12 in combinations with P[4], P[6] and P[8] VP4 genotypes. Genotype G12 predominated in combination with P[8] (54.1%) and P[6] (10.4%) genotypes followed by G1P[6] (8.2%), G3P[6] (6.7%), G2P[4] (5.9%), G8P[6] (3.7%), G2P[6] (0.7%), G3P[8] (0.7%), and G9P[8] (0.7%). Genotype P[6] strains in combination with various G-types represented a substantial proportion (N = 44, 32.6%) of the genotyped strains. Partially typed strains included G12P[NT] (2.2%); G3P[NT] (0.7%); G(NT)P[6] (1.5%); and G(NT)P[8] (0.7%). Mixed infections were found in five specimens (3.7%) in several combinations including G1 + G12P[6], G2 + G3P[6] + P[8], G3 + G8P[6], G3 + G12P[6] + P[8], and G12P[6] + P[8]. The approximately 10% relative frequency of G12P[6] strains detected in this study suggests that this strain is emerging in Cameroon and should be monitored carefully as rotavirus vaccine is implemented in this country, as it shares neither G- nor P-type specificity with strains in the RotaTeq(R) and Rotarix(R) vaccines. These findings are consistent with other recent reports of the global spread and increasing epidemiologic importance of G12 and P[6] strains.

BACKGROUND: India accounts for 22% of the 453,000 global rotavirus deaths among children <5 years annually. The Indian Rotavirus Strain Surveillance Network provides clinicians and public health partners with valuable rotavirus disease surveillance data. Our analysis offers policy-makers an update on rotavirus disease burden with emphasis on regional shifts in rotavirus strain epidemiology in India. METHODS: Children <5 years requiring hospitalization for acute gastroenteritis were selected from 10 representative hospitals in 7 cities throughout India between November 2005 through June 2009. We used a modified World Health Organization protocol for rotavirus surveillance; stool specimens were collected and tested for rotavirus using enzyme immunoassay and reverse-transcription polymerase chain reaction. RESULTS: A total of 7285 stool specimens collected were tested for rotavirus, among which 2899 (40%) were positive for rotavirus. Among the 2899 rotavirus detections, a G-type could not be determined for 662 (23%) and more than one G type was detected in 240 (8%). Of 1997 (69%) patients with only one G-type, the common types were G1 (25%), G2 (21%), G9 (13%), and G12 (10%). The proportion of rotavirus infections attributed to G12 infections rose from 8% to 39% in the Northern region and from 8% to 24% in the Western region. CONCLUSIONS: This study highlights the large, ongoing burden of rotavirus disease in India, as well as interesting regional shifts in rotavirus strain epidemiology, including an increasing detection of G12 rotavirus strains in some regions. While broad heterotypic protection from rotavirus vaccination is expected based on pre- and post-licensure data from other settings, effectiveness assessments and rotavirus strain monitoring after vaccine introduction will be important.

BACKGROUND: We assessed vaccine effectiveness (VE) for RotaTeq(R) (RV5; 3 doses) and Rotarix(R) (RV1; 2 doses) at reducing rotavirus acute gastroenteritis (AGE) inpatient and emergency department (ED) visits in geographically and demographically diverse US children. METHODS: We enrolled children <5 years old hospitalized or visiting the ED with AGE symptoms from November 2009 through June 2010 and from November 2010 through June 2011 at 7 medical institutions. Fecal specimens were tested for rotavirus by enzyme immunoassay and genotyped. Vaccine receipt among laboratory-confirmed rotavirus cases was compared with AGE children negative for rotavirus (rotavirus-negative AGE controls). Regression models calculated VE estimates for each vaccine, age, ethnicity, predominant genotype, and clinical setting. RESULTS: RV5-specific analyses included 359 rotavirus cases and 1,811 rotavirus-negative AGE controls. RV1-specific analyses included 60 rotavirus cases and 155 rotavirus-negative AGE controls. RV5 and RV1 were 84% (CI=78%-88%) and 70% (CI=39%-86%) effective, respectively, against rotavirus-associated ED visits and hospitalizations combined. By clinical setting, RV5 VE against ED and inpatient rotavirus-associated visits was 81% (CI=70%-84%) and 86% (CI=74-91%), respectively. RV1 was 78% (CI= 46%-91%) effective against ED rotavirus disease; study power was insufficient to evaluate inpatient RV1 VE. No waning of immunity was evident during the first four years of life for RV5, nor during the first two years of life for RV1. RV5 provided statistically significant genotype-specific protection against each of the four major circulating rotavirus strains (G1P[8], G2P[4], G3P[8], G12P[8]), while RV1 also had a statistically significant VE for the most common genotype, G3P[8]. CONCLUSION: Both RV5 and RV1 significantly protected against medically-attended rotavirus gastroenteritis in this real-world assessment.

Skin immunization is effective against a number of infectious diseases, including smallpox and tuberculosis, but is difficult to administer. Here, we assessed the use of an easy-to-administer microneedle (MN) patch for skin vaccination using an inactivated rotavirus vaccine (IRV) in mice. Female inbred BALB/c mice in groups of six were immunized once in the skin using MN coated with 5mcg or 0.5mcg of inactivated rotavirus antigen or by intramuscular (IM) injection with 5mcg or 0.5mcg of the same antigen, bled at 0 and 10 days, and exsanguinated at 28 days. Rotavirus-specific IgG titers increased over time in sera of mice immunized with IRV using MN or IM injection. However, titers of IgG and neutralizing activity were generally higher in MN immunized mice than in IM immunized mice; the titers in mice that received 0.5mcg of antigen with MN were comparable or higher than those that received 5mcg of antigen IM, indicating dose sparing. None of the mice receiving negative-control, antigen-free MN had any IgG titers. In addition, MN immunization was at least as effective as IM administration in inducing a memory response of dendritic cells in the spleen. Our findings demonstrate that MN delivery can reduce the IRV dose needed to mount a robust immune response compared to IM injection and holds promise as a strategy for developing a safer and more effective rotavirus vaccine for use among children throughout the world.

Vaccine or vaccine-reassortant rotavirus strains were detected in fecal specimens from 5 of 106 (4.7%) immunocompetent children who required treatment for rotavirus gastroenteritis at a large pediatric hospital in Texas in 2009-2010. Four strains were related to pentavalent rotavirus vaccine, whereas one was related to monovalent rotavirus vaccine. The contribution of these strains to each patient's illness was unclear given that 2 patients had prominent respiratory symptoms and 2 were concurrently infected with another pathogen (group F adenovirus and norovirus). Continued monitoring is necessary to assess the role of vaccine strains and vaccine-reassortant strains in pediatric rotavirus infections.

Systematic hospital-based surveillance of rotavirus strains has been conducted in Taiwan to track baseline strain prevalence before and during the introduction of vaccines and to document any strain changes that occur as vaccine use increases (1). Both Rotarix and RotaTeq have been available via Taiwan's private pharmaceutical market since September 2006. As a result of more rigorous surveillance and the exclusive use of gene sequencing for strain genotyping, a variety of unusual strains were detected between 2005 and 2010 (2,3). A strain with rare VP7 and VP4 genotypes, RVA/Human-wt/TWN/04-97s379/2008/G8P[14] (hereafter referred to as 04-97s379), was identified in a 23-month-old boy treated for fever, diarrhea, and vomiting at an outpatient clinic in Changhua, Taiwan. This was the only G8P[14] strain identified among the 1,273 human rotaviruses that were genotyped during this 6-year surveillance period in Taiwan. Because human G8P[14] strains have only been reported in a few countries, including only a single country in the World Health Organization Western Pacific Region, Australia (4), it was of interest to characterize the G8P[14] rotavirus strain detected in Taiwan. | The oligonucleotide primers used to amplify and sequence full-length or partial open reading frames of the VP7 (1,062 bp), VP4 (831 bp), VP6 (1,356 bp), and NSP4 (738 bp) genes (GenBank accession numbers, JX1543843, JX1542665, JX1543853, and JX1542003, respectively) have been described elsewhere (3). For phylogenetic analysis, nucleotide sequences of related strains were retrieved from GenBank and compared with the Taiwanese strain 04-97s379 using the MEGA4 software (5).

Recently, two rotavirus vaccines have been recommended for routine immunization of infants worldwide. These vaccines proved efficacious during clinical trials and field use in both developing and developed countries, and appear to provide good protection against a range of rotavirus genotypes, including some that are not included in the vaccines. However, since conclusive data that the vaccines will protect against a wide variety of rotavirus strains are still lacking and since vaccines may exert some selection pressure, a detailed picture of global strain prevalence from the pre-rotavirus vaccine era is important to evaluate any potential changes in circulating strains observed after widespread introduction of rotavirus vaccines. Thus, we systematically reviewed rotavirus genotyping studies spanning a 12-year period from 1996 to 2007. In total, approximately 110,000 strains were genotyped from 100 reporting countries. Five genotypes (G1-G4, and G9) accounted for 88% of all strains, although extensive geographic and temporal differences were observed. For example, the prevalence of G1 strains declined from 2000 onward, while G3 strains re-emerged, and G9 and G12 strains emerged during the same period. When crude strain prevalence data were weighted by region based on the region's contribution to global rotavirus mortality, the importance of genotypes G1 and G9 strains that were more prevalent in regions with low mortality was reduced and conversely the importance of G8 strains that were more prevalent in African settings with greater contribution to global rotavirus mortality was increased. This study provides the most comprehensive, up-to-date information on rotavirus strain surveillance in the pre-rotavirus vaccine era and will provide useful background to examine the impact of rotavirus vaccine introduction on future strain prevalence.

In 2009, three children were hospitalized in Rochester, NY, with sequence-confirmed G8P[4] rotavirus gastroenteritis-the first U.S. detection of this uncommon strain more typically found in Africa. Continued monitoring of G8P[4] and other rotavirus genotypes not represented in current vaccines is essential to assess whether vaccination will result in an increase in prevalence of these strains.

Rotavirus vaccines have had a dramatic impact on morbidity and mortality from diarrhea among children in high- and middle-income countries that have introduced the vaccine into their national immunization programs. Widespread introduction of rotavirus vaccine in developing countries is imminent and their full potential in reducing the global burden from severe childhood diarrhea may soon be realized. The objectives of this paper are to describe the remaining issues and challenges in ensuring the success of the global rotavirus vaccination program and to discuss further research needed to help address them.

Rotavirus G3P[3] strains have been reported from a variety of species including humans, cats, dogs, monkeys, goats, and cows. Here, we report the characterization of the first human G3P[3] rotavirus from East Asia identified in a 2-year-old child who was treated in a hospital's emergency ward in Taiwan in February 2005. Sequence and phylogenetic analysis demonstrated a close genetic relationship between the VP4, VP6, VP7, and NSP4 genes of Taiwanese G3P[3] strain 04-94s51 and an Italian canine strain isolated a decade ago, suggesting a canine origin for the Taiwanese strain. In contrast, the Taiwanese strain was only moderately related to well-characterized canine-origin human G3P[3] strains Ro1845 and HCR3, suggesting a distinct origin for the rotavirus strain from Taiwan.

Genotype P[25] rotaviruses are rare and to date have been reported to occur only in a few countries of mainland Asia. Here we report the molecular characterization of a novel human rotavirus genotype combination, G3P[25], detected in a 17-month-old child hospitalized due to severe gastroenteritis during 2009 in central Taiwan. Sequencing and phylogenetic analysis of the VP4 gene demonstrated a distinct origin from other strains bearing the P[25] VP4 gene, whereas the VP7, VP6 and NSP4 gene phylogenies identified common origins with cognate genes of other, presumed human-porcine reassortment Taiwanese strains. These results suggest that interactions between human and animal strains appear to contribute to the generation of genetic and antigenic diversity of rotavirus strains, with potential public health importance in Taiwan. Clin Microbiol Infect 2011; 17: 1570-1573

OBJECTIVE: To determine the vaccine effectiveness (VE) of complete and partial vaccination with the pentavalent rotavirus vaccine (RV5) in the prevention of rotavirus acute gastroenteritis (AGE) hospitalizations and emergency department visits during the first 3 rotavirus seasons after vaccine introduction. METHODS: Active, prospective population-based surveillance for AGE and acute respiratory infection (ARIs) in inpatient and emergency department settings provided subjects for a case-control evaluation of VE in 3 US counties from January 2006 through June 2009. Children with laboratory-confirmed rotavirus AGE (cases) were matched according to date of birth and onset of illness to 2 sets of controls: children with rotavirus-negative AGE and children with ARI. The main outcome measure was VE with complete (3 doses) or partial (1 or 2 doses) RV5 vaccination. RESULTS: Of age-eligible children enrolled, 18% of cases, 54% of AGE controls, and 54% of ARI controls received ≥1 dose of RV5. The VE of RV5 for 1, 2, and 3 doses against all rotavirus genotypes with the use of rotavirus-negative AGE controls was 74% (95% confidence interval [CI]: 37%-90%), 88% (95% CI: 66%-96%), and 87% (95% CI: 71%-94%), respectively, and with the use of ARI controls was 73% (95% CI: 43%-88%), 88% (95% CI: 68%-95%), and 85% (95% CI: 72%-91%), respectively. The overall VE estimates were comparable during the first and second years of life and against AGE caused by different rotavirus strains. CONCLUSION: RV5 was highly effective in preventing severe rotavirus disease, even after a partial series, with protection persisting throughout the second year of life.

We report the first detection of a G6P[14] rotavirus strain in Egypt from the stool of a child participating in a hospital-based diarrhea surveillance study conducted throughout the year 2004. Rotavirus infection was initially detected using a rotavirus group A VP6 enzyme immunoassay; the P (VP4) and G (VP7) genotypes of the strain were identified by RT-PCR. We sequenced the VP7 gene and the VP8* portion of the VP4 gene and the strain displayed the strongest identity to the VP7 [>94% nucleotides (nt), >97% amino acids (aa)] and VP4 (>93% nt, >98% aa) sequences of PA169, a novel G6P[14] strain first isolated from a child in Italy during the winter of 1987. Additional sequencing and analysis of the other remaining structural (VP1-VP3, VP6) and non-structural (NSP1-NSP5) proteins support this animal-to-human reassortment theory. According to the full genome classification system, the G6P[14] strain (EGY3399) was assigned to G6-P[14]-I2-R2-C2-M2-A11-N2-T6-E2-H3 genotypes. The greatest similarity of EGY3399 NSP4 and NSP5 gene sequences were to those of ovine and simian origin, respectively. Coupled with other observations, our results suggest G6P[14] isolates rarely cause severe diarrhea in Egyptian children, and support other studies that indicate animal rotavirus contribute to the genetic diversity of rotavirus detected from humans through interspecies transmission and single or multiple segments reassortment.

Studies on rotavirus vaccine shedding and its potential transmission within households including immunocompromised individuals are needed to better define the potential risks and benefits of vaccination. We examined fecal shedding of pentavalent rotavirus vaccine (RV5) for 9 days following the first dose of vaccine in infants between 6 and 12 weeks of age. Rotavirus antigen was detected by enzyme immunoassay (EIA), and vaccine-type rotavirus was identified by nucleotide sequencing based on genetic relatedness to the RV5 VP6 gene. Stool from 22 (21.4%) of 103 children contained rotavirus antigen-positive specimens on ≥1 post-vaccination days. Rotavirus antigen was detected as early as post-vaccination day 3 and as late as day 9, with peak numbers of shedding on post-vaccination days 6 through 8. Vaccine-type rotavirus was detected in all 50 antigen-positive specimens and 8 of 8 antigen-negative specimens. Nine (75%) of 12 EIA-positive and 1 EIA-negative samples tested culture-positive for vaccine-type rotavirus. Fecal shedding of rotavirus vaccine virus after the first dose of RV5 occurred over a wide range of post-vaccination days not previously studied. These findings will help better define the potential for horizontal transmission of vaccine virus among immunocompromised household contacts of vaccinated infants for future studies.

We previously reported the detection of genotype P[19] rotavirus strains from children hospitalized with acute dehydrating diarrhea during a 5-year surveillance period in Taiwan. The characterization of five P[19] strains (0.4% of all typed), including three G3P[19], a novel G5P[19], and a unique G9P[19] genotype is described in this study. Phylogenetic analysis of the VP4, VP7, VP6, and NSP4 genes was performed, which demonstrated novel lineages for respective genotypes of the VP4 and the VP7 genes. The sequence similarities of the P[19] VP4 gene among Taiwanese human strains was higher (nt, 91.5-96.2%; aa, 93.7-97.6%) than to other P[19] strains (nt, 83.5-86.6%; aa, 89.4-94.1%) from different regions of the world. The VP7 gene of the three G3P[19] Taiwanese strains shared up to 93.4% nt and 97.5% aa identity to each other but had lower similarity to reference strain sequences available in GenBank (nt, <90.1%; aa, <95.6%). Similarly, the VP7 gene of the novel G5P[19] strain was only moderately related to the VP7 gene of reference G5 strains (nt, 82.2-87.3%; aa, 87.0-93.1%), while the VP7 gene of the single G9P[19] strain was genetically distinct from other known human and animal G9 rotavirus strains (nt, ≤92.0%; aa, ≤95.7%). Together, these findings suggest that the Taiwanese P[19] strains originated by independent interspecies transmission events. Synchronized surveillance of human and animal rotaviruses in Taiwan should identify possible hosts of these uncommon human rotavirus strains. J. Med. Virol. 83:1279-1287, 2011. (c) 2011 Wiley-Liss, Inc.

After discovery in the early 1980s, Rotavirus A serotype G9 was detected infrequently for almost a decade. Since the mid-1990s, however, serotype G9 has emerged to become a globally common strain linked to the introduction of a single, new genetic variant of G9 VP7 gene. Studies have demonstrated that genetically divergent G9 strains co-circulated at low frequency with the emerging variants. Examples include unique U.S. G9 strains Om46/Hu/USA/1998 and Om67/Hu/USA/1998, isolated in Omaha during the 1997-1998 rotavirus season, that are more closely related phylogenetically to reference strains from the 1980s than to most emerging G9 strains from the U.S. and globally. Here, we sequenced the VP7 full open reading frame for all available G9 strains (n=12) identified in Omaha during 1996-2000 seasons to investigate their epidemiology and evolution. In addition, the full or partial length open reading frames of the remaining 10 genes for five divergent Om46-like strains and one modern G9 variant were sequenced to evaluate their potential origin. Our findings suggest that Om46-like G9 strains may have been introduced into humans recently, perhaps in 1997-1998 when it was first detected, and the presumed original host of this VP7 gene variant may have been an animal species based on the unexpected detection of porcine rotavirus related NSP2 gene in the genome. The relatively high fitness of Om46-like strains during the 1997-1998 rotavirus season, 1 year after the globally important G9 variant was documented to be already spreading in the study area and other sites of the United States, appears to parallel findings on seasonal replacement of various genetic and antigenic variants of other common human rotavirus antigen specificities.