Abstract Background Introduction of rotavirus vaccines into national immunization programs (NIPs) could result in strain selection due to vaccine-induced selective pressure. This study describes the distribution and diversity of rotavirus genotypes before and after rotavirus vaccine introduction into the Australian NIP. State-based vaccine selection facilitated a unique comparison of diversity in RotaTeq and Rotarix vaccine states. Methods From 1995 to 2015, the Australian Rotavirus Surveillance Program conducted genotypic analysis on 13051 rotavirus-positive samples from children <5 years of age, hospitalized with acute gastroenteritis. Rotavirus G and P genotypes were determined using serological and heminested multiplex reverse-transcription polymerase chain reaction assays. Results G1P was the dominant genotype nationally in the prevaccine era (1995–2006). Following vaccine introduction (2007–2015), greater genotype diversity was observed with fluctuating genotype dominance. Genotype distribution varied based on the vaccine implemented, with G12P dominant in states using RotaTeq, and equine-like G3P and G2P dominant in states and territories using Rotarix. Conclusions The increased diversity and differences in genotype dominance observed in states using RotaTeq (G12P), and in states and territories using Rotarix (equine-like G3P and G2P), suggest that these vaccines exert different immunological pressures that influence the diversity of rotavirus strains circulating in Australia. rotavirus, genotype, RotaTeq, Rotarix, selective pressure Rotavirus vaccines have been successfully implemented in the routine immunization programs of 93 countries . The globally licensed rotavirus vaccines, RotaTeq (Merck, West Point, Pennsylvania) and Rotarix (GSK Biologics, Rixensart, Belgium), have been associated with a significant reduction in rotavirus hospitalizations and all-cause gastroenteritis deaths in all settings where they have been introduced [2–4]. However, these vaccines have different genome compositions and antigenic characteristics. Rotarix is a single attenuated human G1P rotavirus strain, administered in a 2-dose oral regimen at 2 and 4 months of age . RotaTeq combines 5 separate bovine-human reassortant strains, each containing a human gene encoding the outer capsid VP7 or VP4 protein (G1, G2, G3, G4, or P) within a backbone of a bovine rotavirus strain . RotaTeq is administered in a 3-dose oral regimen at 2, 4, and 6 months of age. The outer capsid proteins, VP7 and VP4, elicit neutralizing antibodies implicated in genotype-specific and genotype cross-reactive protection [7, 8]. Both vaccines have been reported to protect against severe disease caused by the 5 common VP7 genotypes (G1, G2, G3, G4, and G9) and VP4 genotypes (P, P, and P); however, they also provide broad heterotypic protection against other, less common genotypes . The mechanism and extent to which cross-protection occurs is not well elucidated, nor whether this could impact vaccine escape. Rotavirus vaccination was introduced into the Australian national immunization program (NIP) for all infants on 1 July 2007 . Unlike other countries and regions, Australia allowed each state and territory to independently decide which vaccine to implement in the NIP through a competitive tender process. As a result, Queensland, South Australia, and Victoria selected to use RotaTeq, and the Australian Capital Territory, New South Wales, Northern Territory, and Tasmania selected to use Rotarix (Figure 1). Western Australia initially selected Rotarix, before changing to RotaTeq in 2009. Rotavirus vaccine coverage for 2 or 3 doses (depending on vaccine) in Australia is high, reported at 86.1% by the end of 2015 . Rotavirus vaccines have reduced rotavirus-related hospitalizations in Australia, in both the age group eligible for rotavirus vaccination and nonvaccinated children born prior to vaccine introduction, suggestive of an indirect benefit of rotavirus vaccination . RotaTeq vaccine effectiveness in Queensland is estimated at 89.3% for rotavirus hospitalizations, and in New South Wales, >77% reduction in acute gastroenteritis (AGE) emergency presentations has been observed following Rotarix introduction [2, 13]. The state-based vaccine tender has provided a unique opportunity to observe the impact of RotaTeq and Rotarix introduction on genotype diversity, and to compare genotype distribution between states and territories Australia-wide. Figure 1. View largeDownload slide Pattern of state-based vaccine use within the national immunization program in Australia. Queensland, South Australia, and Victoria implemented RotaTeq (light gray); Australian Capital Territory, New South Wales, Northern Territory, and Tasmania implemented Rotarix (dark gray). Western Australia initially used Rotarix but switched to RotaTeq in 2009. Circles represent locations of collaborating centers contributing samples to the Australian Rotavirus Surveillance Program. Figure 1. View largeDownload slide Pattern of state-based vaccine use within the national immunization program in Australia. Queensland, South Australia, and Victoria implemented RotaTeq (light gray); Australian Capital Territory, New South Wales, Northern Territory, and Tasmania implemented Rotarix (dark gray). Western Australia initially used Rotarix but switched to RotaTeq in 2009. Circles represent locations of collaborating centers contributing samples to the Australian Rotavirus Surveillance Program. Variation in circulating rotavirus strains has been observed in the years prior to the induction of rotavirus vaccines. Molecular epidemiological studies worldwide identified >60 G/P combinations in humans, although 90% of strains belonged to 1 of 5 common genotypes (G1P, G2P, G3P, G4P, and G9P) [14, 15]. The impact of rotavirus vaccines on the natural pattern of circulating rotavirus strains is not known. Documenting changes in rotavirus genotype prevalence, recognizing emergence of rare or uncommon genotypes, and identifying potential vaccine escape strains will inform future vaccination strategies and the development of new rotavirus vaccines. Mass introduction of other non rotavirus live vaccines, such as hepatitis B vaccine, have previously been shown to affect the diversity of circulating strains within a population, where strain replacement, emergence of novel strains, and vaccine escape strains have been observed . The Australian Rotavirus Surveillance Program has monitored the rotavirus genotypes present in children hospitalized with rotavirus-associated AGE in Australia since 1989 . Nineteen collaborating laboratories across Australia collect rotavirus-positive specimens from children <5 years of age hospitalized with AGE. In the current study, we investigated the temporal diversity and geographic trends of rotavirus genotypes observed in children <5 years of age, hospitalized with AGE in Australia from 1995 to 2015. The specific aims were to (1) compare rotavirus strain diversity before and after vaccine introduction, and (2) determine whether differences in genotype diversity and distribution exist between states, based on the vaccine implemented. This state-by-state analysis provides a unique opportunity to compare and contrast the effect of both RotaTeq and Rotarix on the distribution and diversity of wild-type rotavirus strains. METHODS Study Design This study represents a longitudinal analysis of the rotavirus genotypes detected in faecal samples collected from children <5 years of age, who were hospitalized with AGE in Australia. The study period comprises the 12 years prior to rotavirus vaccine introduction into the NIP in Australia (1995–2006), and the 9 years following vaccine introduction (2007–2015). Rotavirus-positive samples were sent to the National Rotavirus Reference Centre (NRRC) laboratory at the Murdoch Children’s Research Institute (MCRI) by 19 laboratories and hospitals collaborating in the Australian Rotavirus Surveillance Program (Figure 1 and Supplementary Table 1). Collaborating centers analyzed fecal samples for the presence of rotavirus using enzyme immunoassay (EIA) or latex agglutination. Rotavirus-positive specimens were then stored at –20°C to –80°C, and the de-identified samples were forwarded at regular intervals each year to the NRRC laboratory, together with metadata including date of collection, date of birth, sex, and postcode. Upon receipt, samples were allocated a unique laboratory code and entered into the NRRC sample-tracking database (Excel and REDCap). Samples were then stored at –80°C until analyzed. The presence of rotavirus antigen was confirmed using ProSpecT Rotavirus Test, a commercial rotavirus EIA (Thermo Fisher, Australia), as per the manufacturer’s instructions. Samples confirmed as rotavirus positive underwent genotyping analysis, whereas unconfirmed specimens (EIA negative) were not processed further. Rotavirus Genotyping Specimens processed prior to 2007 were serotyped using an in-house monoclonal antibody–based serotyping EIA . This comprised of a panel of monoclonal antibodies specific to the major outer capsid protein (VP7) of group A human rotavirus serotypes G1, G2, G3, G4, and G9 . P-genotyping and reverse-transcription polymerase chain reaction (RT-PCR) were not routinely performed prior to 2007. For samples that could not be assigned a serotype or were processed after 2007, rotavirus G and P genotypes were determined using a heminested multiplex RT-PCR assay . Viral RNA was extracted from 10%–20% (w/v) fecal extracts using the QIAamp Viral RNA mini extraction kit (QIAGEN, Hilden, Germany) according to the manufacturer’s instructions. The first-round RT-PCR reactions were performed using the QIAGEN 1-step RT-PCR kit, using VP7 primers VP7F and VP7R, or VP4 primers VP4F and VP4R [20, 21]. The second-round genotyping PCR reactions were conducted using the AmpliTaq DNA Polymerase with Buffer II (Applied Biosystems, Foster City, California), together with specific oligonucleotide primers for G types (G1, G2, G3, G4, G8, G9, and G12) or P types (P, P, P, P, P, and P), as previously described . The G and P genotype of each sample was assigned using agarose gel analysis of second-round PCR products. The VP7 nucleotide sequence from PCR-nontypeable samples was determined by Sanger sequencing, as the primers used in the current G-typing protocol could not assign a genotype to equine-like G3, G12, and unusual or uncommon rotavirus strains. Suspect vaccine excretion cases from RotaTeq states that could not be P-typed, or G1P strains from infants within the age range of recent vaccination in Rotarix states, were also sequenced. First-round VP7 or VP4 amplicons were purified for sequencing using commercial kits as previously described . Purified DNA together with oligonucleotide primers (VP7F/R or VP4F/R) were sent to the Australian Genome Research Facility (Melbourne) and sequenced using an ABI PRISM BigDye Terminator Cycle Sequencing Reaction Kit (Applied Biosystems) in an Applied Biosystems 3730xl DNA Analyzer. Sequences were edited with Sequencher version 4.10.1. Genotype assignment was determined using BLAST (http://blast.ncbi.nlm.nih.gov/Blast.cgi) and RotaC version 2.0 (http://rotac.regatools.be) . Data Analysis Samples were excluded if patient age was unknown or >5 years, or if a duplicate sample was provided. Samples containing a rotavirus vaccine strain were also excluded (Figure 2). According to the date of collection, samples were divided into prevaccine era (1995–2006) and vaccine era (2007–2015). Vaccine group was assigned according to the state or territory where the sample was collected (RotaTeq group: Queensland, South Australia, Victoria, and Western Australia [before 1 May 2009]; Rotarix group: Australian Capital Territory, New South Wales, Northern Territory, and Western Australia [1 May 2009 or later]). Data are presented as the proportion (percentage) of a specific genotype compared to the total number of strains collected for that era, per vaccine group, and for each state and territory. Figure 2. View largeDownload slide Stool sample flowchart. Abbreviation: WA, Western Australia. Figure 2. View largeDownload slide Stool sample flowchart. Abbreviation: WA, Western Australia. RESULTS During the period 1995–2015, a total of 21545 rotavirus-positive fecal specimens were received from collaborating laboratories in the 8 states and territories across Australia. Of these, 13051 were confirmed as rotavirus positive and included in the final analysis (Figure 2). Reasons for exclusion included insufficient sample (n = 760), missing or not processed (n = 468), duplicate (n = 327), age >5 years (n = 2280), age unknown (n = 1064), negative EIA result when analyzed at MCRI (n = 3439), and identification of vaccine strain (n = 156) (Figure 2). In the prevaccine era (1995–2006), 9301 samples were analyzed; 3318 samples from states that subsequently implemented the RotaTeq vaccine, and 5983 samples from states and territories that subsequently implemented the Rotarix vaccine. Following vaccine introduction (2007–2015), 3750 samples were analyzed; 2179 from children in states that had implemented RotaTeq vaccine and 1571 in states and territories that had implemented Rotarix vaccine. Increased Genotypic Diversity and Unusual Strains Identified Following Vaccine Introduction The diversity of rotavirus genotypes observed was greater in the period following rotavirus vaccine introduction (Figure 3). In the prevaccine era, the common circulating genotypes were G1, G2, G3, G4, and G9, which represented 82.9% (n = 7714 of 9301) of all samples genotyped in that period. G1 strains were the predominant genotype, representing 53.4% (4966/9301) of all samples genotyped, followed by G9 (1349/9301 [14.5%]), G3 (599/9301 [6.4%]), G2 (434/9301 [4.7%]), and G4 (366/9301 [3.9%]). In contrast, following vaccine introduction (2007–2015), these 5 common genotypes were identified in only 63% (2365/3750) of all samples genotyped (Figure 3). The most common genotypes identified in the vaccine era were G1P (983/3750 [26.2%]), G2P (780/3750 [20.8%]), and G12P (683/3750 [18.2%]) (Figure 3). Other genotypes identified following vaccine introduction included a novel equine-like G3P (343/3750 [9.1%]) , G3P (312/3750 [8.3%]), G9P (226/3750 [6%]), and G4P (64/3750 [1.7%]) (Figure 3). G12P, only identified in a single outbreak involving 10 patients in the prevaccine era, emerged as a dominant genotype from 2012 onward; identified in 683 samples between 2012 and 2015. Previously uncommon VP7 genotypes such as G8, G10, and other animal-reassortant strains (excluding equine-like G3P strains), were also detected more frequently in the vaccine era (n = 63) compared to the prevaccine era (n = 17) (Supplementary Table 2). This increase, together with the emergence of the equine-like G3P strain and G12P strains, suggests that a more diverse population of genotypes was circulating following vaccine introduction. Figure 3. View largeDownload slide Comparison of genotype distribution (% of all rotavirus strains) before and after rotavirus vaccine introduction to the Australian national immunization program. Colors represent specific rotavirus genotypes. Samples with an unusual genotype are listed in Supplementary Table 2. Data are presented as the proportion (%) of a specific genotype compared to the total strains collected. Figure 3. View largeDownload slide Comparison of genotype distribution (% of all rotavirus strains) before and after rotavirus vaccine introduction to the Australian national immunization program. Colors represent specific rotavirus genotypes. Samples with an unusual genotype are listed in Supplementary Table 2. Data are presented as the proportion (%) of a specific genotype compared to the total strains collected. Differences in the Geographical Distribution of Genotypes According to Vaccine Use The pattern of rotavirus genotypes causing hospitalization in children <5 years of age was similar across states and territories in the prevaccine era, with G1P the dominant genotype detected (Figure 4A and 4B). The higher proportion of G9P and G3P strains identified in states and territories that would later introduce Rotarix may have been influenced by outbreaks in the Northern Territory due to G9P in 2001–2003, and G3P in 2003–2006, which spread to other states (Supplementary Figure 1A and 1B) . Figure 4. View largeDownload slide Comparison of rotavirus G and P type (% of all rotavirus strains) based on vaccine used within the state-based national immunization program (NIP). A, Genotype distribution prior to vaccine introduction in Australia categorized by the vaccine to be introduced into the state-based immunization program. B, Genotype distribution remained consistent across all states and territories in the prevaccine era. C, Genotype distribution following vaccine introduction in Australia, categorized according to the vaccine implemented in the state-based NIP. D, Within vaccine groups, genotype distribution remained consistent across all states and territories following vaccine introduction. Samples with an unusual genotype are listed in Supplementary Table 2. Colors represent specific rotavirus genotypes. Abbreviations: ACT, Australian Capital Territory; NSW, New South Wales; NT, Northern Territory; QLD, Queensland; SA, South Australia; Tas, Tasmania; Vic, Victoria; WA, Western Australia. Figure 4. View largeDownload slide Comparison of rotavirus G and P type (% of all rotavirus strains) based on vaccine used within the state-based national immunization program (NIP). A, Genotype distribution prior to vaccine introduction in Australia categorized by the vaccine to be introduced into the state-based immunization program. B, Genotype distribution remained consistent across all states and territories in the prevaccine era. C, Genotype distribution following vaccine introduction in Australia, categorized according to the vaccine implemented in the state-based NIP. D, Within vaccine groups, genotype distribution remained consistent across all states and territories following vaccine introduction. Samples with an unusual genotype are listed in Supplementary Table 2. Colors represent specific rotavirus genotypes. Abbreviations: ACT, Australian Capital Territory; NSW, New South Wales; NT, Northern Territory; QLD, Queensland; SA, South Australia; Tas, Tasmania; Vic, Victoria; WA, Western Australia. In the first 5 years following vaccine introduction, no single genotype was dominant Australia-wide (Supplementary Figure 1). In 2012–2015, G12P emerged as the dominant genotype in all states that had introduced the RotaTeq vaccine (Supplementary Figure 1A), representing 30.5% (665/2179) of all strains genotyped (Figure 4C). In contrast, G12P strains were only identified in 1.1% (18/1571) of all strains in the states and territories that introduced the Rotarix vaccine (Figure 4C and D). G2P became a dominant genotype in states that implemented Rotarix, identified in 26.7% (419/1571) of samples, compared to 16.6% (361/2179) of samples from states using RotaTeq (Figure 4C and 4D). Equine-like G3P strains emerged across 3 consecutive years (2013–2015), and was observed in 83% (117/141) of samples collected in Rotarix states and territories in 2013, 23.1% (24/104) in 2014, and 49.7% (74/149) in 2015 (Supplementary Figure 1B). Equine-like G3P and G9P strains were identified at a higher frequency in states and territories using Rotarix (equine-like G3P, 13.7% [215/1571]; G9P, 11.8% [185/1571]) compared to states using RotaTeq (equine-like G3P, 5.9% [128/2179]; G9P, 1.9% [41/2179]). When analyzed by state, these patterns of dominance remained consistent within vaccine groups (Figure 4D). In this study, Western Australia was analyzed separately as the vaccine in the NIP changed in May 2009 from Rotarix to RotaTeq (Supplementary Figure 1C). For the period up to 2009, the circulating genotype patterns were similar to other states using Rotarix (Supplementary Figure 1B and 1C). However, from 2010 onward, the genotype distribution changed to reflect patterns observed within RotaTeq states (Supplementary Figure 1A and 1C). One exception was the large proportion of equine-like G3P samples identified in 2013, which was similar to states and territories using Rotarix. DISCUSSION This study demonstrates that the introduction of rotavirus vaccines into the NIP in Australia altered the diversity and distribution of circulating rotavirus genotypes in children aged <5 years who were hospitalized with rotavirus gastroenteritis. Historically, rotavirus genotype distribution has shown temporal and geographic movement across Australia, where strains spread across the country over a period of 1–2 years (eg, genotype G9P) . This geographic and temporal pattern has been disrupted in the vaccine era, with adjacent states using different vaccines exhibiting varied patterns of genotype diversity maintained over many years. This analysis highlighted the importance of sustaining rotavirus surveillance programs, as critical differences in genotype distribution between vaccine locations were not obvious within the first 5 years of rotavirus vaccine introduction. Rotavirus diversity is generated by genetic drift, genetic shift, and zoonotic transmission . Vaccine-induced immune pressure may be an additional selective pressure that leads to the evolution of rotavirus strains capable of causing severe disease in vaccinated children. In this study, sustained dominance of G12P was observed in states using RotaTeq, while dominance of G2P and equine-like G3P was observed in states and territories using Rotarix. This is highly suggestive of vaccine-specific selection pressure, as these observations occurred within a country with high vaccine coverage and demonstrated vaccine effectiveness. The differences observed in adjacent states and territories using either RotaTeq or Rotarix cannot be explained by geographical or demographic differences (Figure 1). However, these differences could be due to vaccine composition and antigenic characteristics . Rotarix contains a monovalent human G1P strain, and has been shown to elicit heterotypic protection against non-G1P strains, whereas the pentavalent human-bovine reassortant vaccine, RotaTeq, generates homotypic protection against each of the G1, G2, G3, G4, and P strains contained in the vaccine and has been shown to elicit heterotypic protection. The ability of each vaccine to generate broader heterotypic protection is not well defined . This study reports an increased detection of previously rare or novel genotypes emerging in the vaccine era, supporting the hypothesis that widespread vaccine use may increase strain diversity. However, emerging genotypes have also been detected in countries with low coverage or no vaccination programs [26, 27]. For example, the novel equine-like G3P strain has been detected in countries with a range of vaccine coverage [7, 26, 28–30]. The first report of this strain was from Japan, where rotavirus vaccine coverage was estimated to be 40%–45% . Since then, this strain has been detected in countries with high vaccine coverage (Australia, Brazil, and the United States), moderate vaccine coverage (Germany, Taiwan, and Spain), and no vaccine coverage within the NIP (Hungary, Thailand, and Turkey) . Multiple amino acid differences have been observed in the antigenic regions of the VP7 gene between human wild-type G3P strains and the equine-like VP7 gene in Australia, suggesting that this equine-like strain is antigenically distinct from human strains . The global emergence of this strain, irrespective of vaccine coverage, suggests that vaccines may not be highly effective against this strain. Global movement of rotavirus strains occurs, reflected by the increasing incidence of G12P in countries with and without vaccine coverage [32–35]. In this study, G12P strains were primarily found in states that use RotaTeq. This is difficult to attribute to natural fluctuations or demographic differences. Similar observations were reported in Finland, where reported vaccine (RotaTeq) coverage is >90% . In Finland, greater genotype diversity was observed in the vaccine era, over 2 rotavirus seasons . Of particular interest is that G12P strains emerged during this period and were detected more often in vaccinated children (13.8%) compared with unvaccinated children (6.5%) . The question remains why G12P and equine-like G3P are responsible for a substantial burden of disease in populations with high vaccine coverage such as Australia and Finland . It has been proposed that the VP7 and VP4 antigenic regions of the equine-like G3P and G12P strains could be distinct to that of the Rotarix and RotaTeq vaccines [7, 36, 37], resulting in lower vaccine effectiveness against these strains. G2P strains have increased in circulation in Australia in the vaccine era, particularly in Rotarix states and territories. Despite Rotarix vaccine introduction in the Northern Territory, Australia, an outbreak associated with G2P strains occurred in 2009 . The average age of patients was of vaccine age (5.5 months); however, there was only approximately 50% vaccine coverage, and vaccine effectiveness against rotavirus hospitalizations was only 19% [38, 39]. A waning heterotypic response afforded by Rotarix, combined with low circulating numbers of G2P in the preceding years, could have contributed to a decrease in herd immunity to this genotype . Furthermore, prior exposure to G2P strains may not have generated effective homotypic protection against the outbreak strain, as it exhibited changes in the VP7 gene antigenic region, compared to other contemporary G2P strains . Excluding this outbreak, G2P strains are still a prominent cause of disease in Rotarix states, possibly reflecting limited or short-lasting heterotypic immunity. An increased proportion of G2P strains have also been reported in Brazil and Belgium after introduction of the Rotarix vaccine [40, 41]. Prelicensure efficacy studies could not consistently demonstrate comparable levels of enduring protection for heterotypic strains such as G2P . Despite reporting vaccine effectiveness of 85% against G2P, a study from Belgium described higher incidence rates of G2P in vaccinated hospitalized cases compared with unvaccinated hospitalized cases . It has been hypothesized that a lower efficacy against heterotypic strains such as G2P could drive an alteration in circulating genotypes [38, 40, 42]. In this study, G2P strains account for 16.6% of strains genotyped in states utilizing the RotaTeq vaccine. Comparison of the RotaTeq component strain and G2P strains circulating in RotaTeq states revealed substitutions in antigenic regions that have also been reported in the majority of G2P strains circulating globally over the last decade . The G2 RotaTeq component strain was isolated in 1992; therefore, if contemporary strains continue to accumulate mutations in antigenic regions, the vaccine strains may need to be updated. After vaccine introduction, the dominance of G1P strains has significantly reduced globally . Several studies have revealed that contemporary strains exhibit numerous mutations in antigenic regions compared to the original vaccine strains [25, 36, 45, 46]. A multicountry phylogenetic analysis revealed unique subclusters of strains identified after Rotarix introduction in Belgium and RotaTeq introduction in Victoria, Australia [45, 46]. Furthermore, the increase in G1P detected in 2010–2012 in our study was attributed to the emergence of a G1P outbreak strain that appeared to evade protection from Rotarix in Alice Springs, Northern Territory . These findings, together with the ongoing presence of G1P in a global context, suggest that rotavirus vaccines may need to be reviewed to meet the evolutionary changes that may challenge the success of vaccination programs. This longitudinal, nationwide analysis of rotavirus genotypes was conducted over a 21-year period prior to and following rotavirus vaccine introduction, reporting increases in genotype diversity and detection of unusual rotavirus strains. Differences in genotype dominance and diversity were apparent between states using the RotaTeq vaccine, compared with states and territories using the Rotarix vaccine. This suggests that vaccine-related immune selection pressure occurs and this phenomenon differs between vaccines, supporting our contention that vaccine pressure drives strain selection. Rotavirus vaccines have been shown to be highly efficacious in reducing severe disease; however, rotavirus strains continue to evolve and novel strains continue to emerge. Ongoing surveillance and the use of phylogenetic analysis will be important to provide further insight on the impact of rotavirus vaccines on strain diversity. Supplementary Data Supplementary materials are available at The Journal of Infectious Diseases online. Consisting of data provided by the authors to benefit the reader, the posted materials are not copyedited and are the sole responsibility of the authors, so questions or comments should be addressed to the corresponding author. Notes Author contributions. S. R.-F. coordinated the Australian Rotavirus Surveillance Program from 2010 to 2018; during this period, S. R.-F. collated samples and conducted experiments. S. R.-F. performed the literature search, data collection, analysis, and interpretation; contributed to the study design; and wrote the first draft of the manuscript. N. B.-S., C. M. D., and K. B. performed data collection, data analysis, and data interpretation, and contributed to the study design. C. D. K., G. L. B., R. F. B., D. C., and J. E. B. designed and directed the study. These authors provided conceptual and technical guidance for all aspects of the project including data interpretation and revision of the manuscript. Australian Rotavirus Surveillance Group. R. Alexander, C. Bletchly, S. Bradbury, H. Cook, J. De Boer, C. Farrar, G. Gilmore, R. Givney, G. Harnett, J. Hennessy, G. Higgins, M. Karimi, A. Kesson, D. Kotsanas, M. Lahra, J. Lang, S. Lambert, A. Lawrence, M. Leung, A. Levy, K. Lindsay, M. Lyon, E. Malinksy, J. McLeod, J. McMahon, C. McIver, J. Merif, C. Moffat, F. Moore, F. Morey, G. Nimmo, M. Nissen, T. Olma, W. Rawlinson, H. Reed, K. Ross, S. Schepetiuk, Tilson, L, V. Sintchenko, D. Smith, P. Southwell, I. Tam, and B. Truscott. Acknowledgments. We thank H. Tran for providing technical support, and all collaborating laboratories for their effort in collecting and providing specimens. Previous members of the Enteric Virus Group who contributed to the Australian Rotavirus Surveillance Program include H. Bugg, D. Cannan, R. Clark, P. Masendycz, and E. Palombo. Financial support. The Australian Rotavirus Surveillance Program is supported by research grants from the vaccine companies Commonwealth Serum Laboratories (CSL) and GlaxoSmithKline (ID116120), as well as the Australian Government Department of Health (RFQ1-2015 ARSP). The Murdoch Children’s Research Institute is supported by the Victorian Government’s Operational Infrastructure Support program. C. M. D. is supported through the Australian National Health and Medical Research Council with an Early Career Fellowship (1113269). Potential conflicts of interest. J. E. B. is Director of the Australian Rotavirus Surveillance Program, World Health Organization (WHO) Collaborating Centre for Child Health, and WHO Asia-Pacific Rotavirus Regional reference laboratory; the Research Lead of the RV3-BB rotavirus vaccine program at MCRI; and Chair of a clinical events committee for a trial conducted by the University of Maryland for which MCRI receives payment to compensate for her time. C. D. K. is currently employed as Senior Program Officer, Enteric and Diarrheal Disease, Bill & Melinda Gates Foundation. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed. Presented in part: 12th International Rotavirus Symposium, Melbourne, Australia, September 2016. References 1. World Health Organization. Vaccine in national immunization programme update. 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The Journal of Infectious Diseases – Oxford University Press
Published: May 22, 2018
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