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Burke RM, Payne DC, McNeal M, Conrey SC, Burrell AR, Mattison CP, Casey-Moore MC, Mijatovic-Rustempasic S, Gautam R, Esona MD, Thorman AW, Bowen MD, Parashar UD, Tate JE, Morrow AL, Staat MA. Correlates of Rotavirus Vaccine Shedding and Seroconversion in a U.S. Cohort of Healthy Infants. J Infect Dis 2024:jiae055. [PMID: 38330312 DOI: 10.1093/infdis/jiae055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 01/21/2024] [Accepted: 01/30/2024] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND Rotavirus is a leading cause of severe pediatric gastroenteritis; two highly effective vaccines are used in the US. We aimed to identify correlates of immune response to rotavirus vaccination in a US cohort. METHODS PREVAIL is a birth cohort of 245 mother-child pairs enrolled 2017-2018 and followed for 2 years. Infant stool samples and symptom information were collected weekly. Shedding was defined as RT-PCR detection of rotavirus vaccine virus in stools collected 4-28 days after dose one. Seroconversion was defined as a threefold rise in IgA between the six-week and six-month blood draws. Correlates were analyzed using generalized estimating equations and logistic regression. RESULTS Pre-vaccination IgG (OR=0.84, 95% CI [0.75-0.94] per 100-unit increase) was negatively associated with shedding. Shedding was also less likely among infants with a single-nucleotide polymorphism inactivating FUT2 antigen secretion ("non-secretors") with non-secretor mothers, versus all other combinations (OR 0.37 [0.16-0.83]). Of 141 infants with data, 105 (74%) seroconverted; 78 (77%) had shed vaccine virus following dose one. Pre-vaccination IgG and secretor status were significantly associated with seroconversion. Neither shedding nor seroconversion significantly differed by vaccine product. DISCUSSION In this US cohort, pre-vaccination IgG and maternal and infant secretor status were associated with rotavirus vaccine response.
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Affiliation(s)
- Rachel M Burke
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Daniel C Payne
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Monica McNeal
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Shannon C Conrey
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Allison R Burrell
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Claire P Mattison
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Cherokee Nation Assurance, Arlington, VA, USA
| | - Mary C Casey-Moore
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Rashi Gautam
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Mathew D Esona
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Alexander W Thorman
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Michael D Bowen
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Umesh D Parashar
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jacqueline E Tate
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ardythe L Morrow
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Mary A Staat
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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Differentiation between Wild-Type Group A Rotaviruses and Vaccine Strains in Cases of Suspected Horizontal Transmission and Adverse Events Following Vaccination. Viruses 2022; 14:v14081670. [PMID: 36016292 PMCID: PMC9416126 DOI: 10.3390/v14081670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 11/18/2022] Open
Abstract
Human group A rotaviruses (RVA) are important enteric pathogens, as they are a leading cause of acute gastroenteritis (AGE) in children worldwide. Since 2013, the German Standing Committee on vaccination recommended the routine rotavirus vaccination for infants in Germany. While vaccination has significantly decreased RVA cases and worldwide mortality, in some cases, infants can develop acute gastroenteritis as an adverse reaction after immunization with an attenuated live vaccine. Pediatricians, as well as clinicians and diagnostic laboratories, contacted the Consultant Laboratory for Rotaviruses and inquired whether cases of RVA-positive AGE after vaccination were associated with vaccine or with wild-type RVA strains. A testing algorithm based on distinguishing PCRs and confirmative sequencing was designed, tested, and applied. Diagnostic samples from 68 vaccinated children and six cases where horizontal transmission was suspected were investigated in this study. Using a combination of real-time PCR, fragment-length analysis of amplicons from multiplex PCRs and confirmative sequencing, vaccine-like virus was detected in 46 samples and wild-type RVA was detected in 6 samples. Three mixed infections of vaccine and wild-type RVA were detectable, no RVA genome was found in 19 samples. High viral loads (>1.0 × 107 copies/g stool) were measured in most RVA-positive samples. Furthermore, information on co-infections with other AGE pathogens in the vaccinated study population was of interest. A commercial multiplex PCR and in-house PCRs revealed three co-infections of vaccinated infants with bacteria (two samples with Clostridioides difficile and one sample with enteropathogenic E. coli) and six co-infections with norovirus in a subset of the samples. Human astrovirus was detected in one sample, with suspected horizontal transmission. The cases of suspected horizontal transmission of vaccine RVA strains could not be confirmed, as they either involved wild-type RVA or were RVA negative. This study shows that RVA-positive AGE after vaccination is not necessarily associated with the vaccine strain and provides a reliable workflow to distinguish RVA vaccine strains from wild-type strains.
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Impact of the SARS-CoV-2 Pandemic on the Prevalence and Incidence of Gastrointestinal Viruses in Children up to Five Years Old: a Retrospective Cohort Study. Microbiol Spectr 2022; 10:e0266921. [PMID: 35638853 PMCID: PMC9241842 DOI: 10.1128/spectrum.02669-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim is determining the impact of non-pharmaceutical measures (NPIs) against SARS-CoV-2 in the incidence and prevalence of gastrointestinal viruses (GV) in children. Demographic, analytical, and clinical data of children from which samples were received at the Hospital Universitario La Paz (Madrid, Spain) and that had a gastrointestinal infection with a positive sample through multiplex-PCR for GV were collected. The time periods included were prepandemic (P1): March 14, 2019 to March 14, 2020 and pandemic (P2): March 15, 2020 to March 15, 2021. The global prevalence, relative incidence (RI, per 1,000 admissions) and absolute incidence (AI, per 100,000 population) of GV were compared for both time periods. The prevalence of GV versus SARS-CoV-2 was determined for P2. Seven-hundred and 50 out of 2,547 children analyzed in P1 and 106 out of 1,368 in P2 were positive by PCR for GV (46.3% decrease in P2). Prevalence and RI of GV declined in P2, except for the RI of rotavirus. Adenovirus showed the largest decreased of prevalence and RI (100%), followed by sapovirus. Astrovirus reduction was less pronounced (3.1% versus 0.4%). Norovirus was the most frequent virus in both time periods and its prevalence and RI also decreased in P2 (15.2% versus 4.7% and 3.40 versus 1.74, respectively). Rotavirus had the smallest decrease in prevalence (2.6% versus 2.5%), and its RI increased during P2 from 0.7 to 0.93. After removing the rotavirus vaccine strains from the analysis, the prevalence and RI decreased during P2 (2.1% to 0.7% and 0.5 to 0.3, respectively). The AI decreased during P2 in all GV, and the prevalence of SARS-CoV-2 and GV was inversely proportional over time. Prevalence and incidence of GV have decreased during the pandemic, probably due to the implementation of NPIs against this virus and the reduction of health care attention to infections other than COVID-19. The differences in the decrease of prevalence and incidence for each virus may be explained by differences in the transmission and the resistance in the environment. Prevalence and RI of rotavirus might be biased since the PCR used detects both the infecting and the vaccine strains. IMPORTANCE Our original article contains an analysis of the impact of the measures applied against SARS-CoV-2 on the prevalence and incidence of GV in children. The small number of studies published to date that analyze the impact of these measures individually on each of the GV makes our study of great interest at this time.
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Pitkänen O, Markkula J, Hemming-Harlo M. Sapovirus, Norovirus and Rotavirus Detections in Stool Samples of Hospitalized Finnish Children With and Without Acute Gastroenteritis. Pediatr Infect Dis J 2022; 41:e203-e207. [PMID: 35185141 PMCID: PMC8997665 DOI: 10.1097/inf.0000000000003493] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/24/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND Sapovirus, norovirus and rotavirus are major causes of childhood acute gastroenteritis (AGE) globally. Asymptomatic infections of these viruses have not been extensively studied. AIM To examine the prevalence and the genetic variations of sapovirus, norovirus and rotavirus in children with and without symptoms of AGE. METHODS We collected 999 stool samples from children under 16 years old from September 2009 to August 2011 at Tampere University Hospital, Finland. In total 442 children (44%) had symptoms of AGE and 557 patients (56%) had acute respiratory tract infection (ARTI) only. Samples were examined for sapovirus, norovirus and rotavirus using reverse transcription-polymerase chain reaction and the positive amplicons were sequenced. RESULTS Totally 54% and 14% of the patients in AGE and ARTI groups, respectively, tested positive. All viruses were more frequently detected in AGE patients than in ARTI patients (norovirus, 25% vs. 7.2%, respectively; rotavirus, 24% vs. 6.1%; sapovirus, 5.2% vs. 1.4%). In ARTI patients, the cases were seen most frequently during the first two years of life. Norovirus was the most detected pathogen in both groups with genogroup GII covering ≥97% of norovirus strains. Sapovirus was mostly detected in children under 18 months old without predominating genotype. Rotavirus was often detected after recent rotavirus vaccination and 18% and 88% of the strains were rotavirus vaccine-derived in AGE and ARTI groups, respectively. CONCLUSIONS We showed that the most common viruses causing gastroenteritis in children may be found in the stools of an asymptomatic carrier which may function as a potential reservoir for AGE.
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Affiliation(s)
| | - Jukka Markkula
- From the Vaccine Research Center
- Tampere Center for Child Health Research, Arvo Ylpön katu 34, University of Tampere, Finland
| | - Maria Hemming-Harlo
- Tampere Center for Child Health Research, Arvo Ylpön katu 34, University of Tampere, Finland
- The Pediatric Research Center, Biomedicum Haartmaninkatu 8, University of Helsinki, Finland
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Mandolo JJ, Henrion MYR, Mhango C, Chinyama E, Wachepa R, Kanjerwa O, Malamba-Banda C, Shawa IT, Hungerford D, Kamng’ona AW, Iturriza-Gomara M, Cunliffe NA, Jere KC. Reduction in Severity of All-Cause Gastroenteritis Requiring Hospitalisation in Children Vaccinated against Rotavirus in Malawi. Viruses 2021; 13:2491. [PMID: 34960760 PMCID: PMC8707889 DOI: 10.3390/v13122491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 01/21/2023] Open
Abstract
Rotavirus is the major cause of severe gastroenteritis in children aged <5 years. Introduction of the G1P[8] Rotarix® rotavirus vaccine in Malawi in 2012 has reduced rotavirus-associated hospitalisations and diarrhoeal mortality. However, the impact of rotavirus vaccine on the severity of gastroenteritis presented in children requiring hospitalisation remains unknown. We conducted a hospital-based surveillance study to assess the impact of Rotarix® vaccination on the severity of gastroenteritis presented by Malawian children. Stool samples were collected from children aged <5 years who required hospitalisation with acute gastroenteritis from December 2011 to October 2019. Gastroenteritis severity was determined using Ruuska and Vesikari scores. Rotavirus was detected using enzyme immunoassay. Rotavirus genotypes were determined using nested RT-PCR. Associations between Rotarix® vaccination and gastroenteritis severity were investigated using adjusted linear regression. In total, 3159 children were enrolled. After adjusting for mid-upper arm circumference (MUAC), age, gender and receipt of other vaccines, all-cause gastroenteritis severity scores were 2.21 units lower (p < 0.001) among Rotarix®-vaccinated (n = 2224) compared to Rotarix®-unvaccinated children (n = 935). The reduction in severity score was observed against every rotavirus genotype, although the magnitude was smaller among those infected with G12P[6] compared to the remaining genotypes (p = 0.011). Each one-year increment in age was associated with a decrease of 0.43 severity score (p < 0.001). Our findings provide additional evidence on the impact of Rotarix® in Malawi, lending further support to Malawi's Rotarix® programme.
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Affiliation(s)
- Jonathan J. Mandolo
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
- Department of Biomedical Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre 312225, Malawi
| | - Marc Y. R. Henrion
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Chimwemwe Mhango
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
- Department of Biomedical Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre 312225, Malawi
| | - End Chinyama
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
| | - Richard Wachepa
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
| | - Oscar Kanjerwa
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
| | - Chikondi Malamba-Banda
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
- Centre for Global Vaccine Research, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7BE, UK; (D.H.); (M.I.-G.); (N.A.C.)
- Department of Medical Laboratory Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre 312225, Malawi
| | - Isaac T. Shawa
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
- Department of Medical Laboratory Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre 312225, Malawi
| | - Daniel Hungerford
- Centre for Global Vaccine Research, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7BE, UK; (D.H.); (M.I.-G.); (N.A.C.)
- NIHR Health Protection Research Unit in Gastrointestinal Infections, University of Liverpool, Liverpool L69 7BE, UK
| | - Arox W. Kamng’ona
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
- Department of Biomedical Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre 312225, Malawi
- Centre for Global Vaccine Research, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7BE, UK; (D.H.); (M.I.-G.); (N.A.C.)
| | - Miren Iturriza-Gomara
- Centre for Global Vaccine Research, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7BE, UK; (D.H.); (M.I.-G.); (N.A.C.)
- NIHR Health Protection Research Unit in Gastrointestinal Infections, University of Liverpool, Liverpool L69 7BE, UK
- Centre for Vaccine Innovation and Access, Program for Appropriate Technology in Health (PATH), 1218 Geneva, Switzerland
| | - Nigel A. Cunliffe
- Centre for Global Vaccine Research, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7BE, UK; (D.H.); (M.I.-G.); (N.A.C.)
- NIHR Health Protection Research Unit in Gastrointestinal Infections, University of Liverpool, Liverpool L69 7BE, UK
| | - Khuzwayo C. Jere
- Virology Research Group, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre 312225, Malawi; (J.J.M.); (M.Y.R.H.); (C.M.); (E.C.); (R.W.); (O.K.); (C.M.-B.); (I.T.S.); (A.W.K.)
- Centre for Global Vaccine Research, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7BE, UK; (D.H.); (M.I.-G.); (N.A.C.)
- Department of Medical Laboratory Sciences, School of Life Sciences and Health Professions, Kamuzu University of Health Sciences, Blantyre 312225, Malawi
- NIHR Health Protection Research Unit in Gastrointestinal Infections, University of Liverpool, Liverpool L69 7BE, UK
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Pitkänen O, Markkula J, Hemming-Harlo M. A major decrease of viral acute gastroenteritis in hospitalized Finnish children as rotavirus returns as the most detected pathogen. Int J Infect Dis 2021; 114:273-278. [PMID: 34775115 DOI: 10.1016/j.ijid.2021.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/05/2021] [Accepted: 11/06/2021] [Indexed: 11/30/2022] Open
Abstract
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 1st, 2017 to December 31st, 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.
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Affiliation(s)
- Oskari Pitkänen
- Vaccine Research Center, Arvo Ylpön katu 34, 33014 Tampere University, Finland.
| | - Jukka Markkula
- Vaccine Research Center, Arvo Ylpön katu 34, 33014 Tampere University, Finland.
| | - Maria Hemming-Harlo
- Tampere Center for Child Health Research, Arvo Ylpön katu 34, 33014 Tampere University, Finland; Children's Hospital, 00014 University of Helsinki, Finland.
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Zhou N, Zhou L, Wang B. Genetic Characterizations and Molecular Evolution of VP7 Gene in Human Group A Rotavirus G1. Viruses 2020; 12:v12080831. [PMID: 32751603 PMCID: PMC7472278 DOI: 10.3390/v12080831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/20/2020] [Accepted: 07/29/2020] [Indexed: 01/01/2023] Open
Abstract
Rotavirus group A (RVA) G1 is one leading genotype circulating in humans worldwide, and related molecular information from a global perspective is still limited. Here, we present a comprehensive description of the genetic characterizations and molecular evolution of the RVA G1 VP7 gene. Our results show that RVA G1 can be divided into two lineages and multiple sub-lineages with a relatively high genetic diversity. Vaccine strains are phylogenetic, closer to lineage I. The evolutionary rate of the RVA G1 VP7 gene is 8.869 × 10-4 substitutions/site/year, and its most recent common ancestor was in 1933. The RVA G1 VP7 gene shows a linear evolution at the nucleotide level and a linear accumulation of difference at the amino acid level. Sub-lineage replacement of G1 VP7 gene is also observed and the effective population size of the G1 VP7 gene has had great change in the past decades and has remained stable in recent years. Altogether, the RVA G1 VP7 gene constantly evolves and there is no clear evidence that the evolution of the RVA G1 VP7 gene was influenced by vaccines. Continuous surveillance is still indispensable to evaluate the molecular epidemiology of RVA, especially in the post-vaccination era.
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Affiliation(s)
- Nan Zhou
- Key Laboratory of Environmental Medicine and Engineering of Ministry of Education, Department of Epidemiology and Statistics, School of Public Health, Southeast University, Nanjing 210009, China;
| | - Lu Zhou
- Department of Acute Infectious Diseases, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China;
| | - Bei Wang
- Key Laboratory of Environmental Medicine and Engineering of Ministry of Education, Department of Epidemiology and Statistics, School of Public Health, Southeast University, Nanjing 210009, China;
- Correspondence: ; Tel.: +86-25-83272569
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