Clinical and molecular epidemiology of enterovirus D68 from 2013 to 2020 in Shanghai.

Enterovirus D68 (EV-D68) is an emerging pathogen that has caused outbreaks of severe respiratory disease worldwide, especially in children. We aim to investigate the prevalence and genetic characteristics of EV-D68 in children from Shanghai. Nasopharyngeal swab or bronchoalveolar lavage fluid samples collected from children hospitalized with community-acquired pneumonia were screened for EV-D68. Nine of 3997 samples were EV-D68-positive. Seven of nine positive samples were sequenced and submitted to GenBank. Based on partial polyprotein gene (3D) or complete sequence analysis, we found the seven strains belong to different clades and subclades, including three D1 (detected in 2013 and 2014), one D2 (2013), one D3 (2019), and two B3 (2014 and 2018). Overall, we show different clades and subclades of EV-D68 spread with low positive rates (0.2%) among children in Shanghai between 2013 and 2020. Amino acid mutations were found in the epitopes of the VP1 BC and DE loops and C-terminus; similarity analysis provided evidence for recombination as an important mechanism of genomic diversification. Both single nucleotide mutations and recombination play a role in evolution of EV-D68. Genetic instability within these clinical strains may indicate large outbreaks could occur following cumulative mutations.

Safety and immunogenicity of heterologous boost immunisation with an orally administered aerosolised Ad5-nCoV after two-dose priming with an inactivated SARS-CoV-2 vaccine in Chinese adults: a randomised, open-label, single-centre trial.

BACKGROUND: Due to waning immunity and protection against infection with SARS-CoV-2, a third dose of a homologous or heterologous COVID-19 vaccine has been proposed by health agencies for individuals who were previously primed with two doses of an inactivated COVID-19 vaccine. METHODS: We did a randomised, open-label, controlled trial to evaluate the safety and immunogenicity of heterologous boost immunisation with an orally administered aerosolised adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) in Chinese adults (≥18 years old) who had previously received two doses of an inactivated SARS-CoV-2 vaccine-Sinovac CoronaVac. Eligible participants were randomly assigned (1:1:1) to receive a heterologous booster vaccination with a low dose (1·0 × 1011 viral particles per mL; 0·1 mL; low dose group), or a high dose (1·0 × 1011 viral particles per mL; 0·2 mL; high dose group) aerosolised Ad5-nCoV, or a homologous intramuscular vaccination with CoronaVac (0·5 mL). Only laboratory staff were masked to group assignment. The primary endpoint for safety was the incidence of adverse reactions within 14 days after the booster dose. The primary endpoint for immunogenicity was the geometric mean titres (GMTs) of serum neutralising antibodies (NAbs) against live SARS-CoV-2 virus 14 days after the booster dose. This study was registered with ClinicalTrials.gov, NCT05043259. FINDINGS: Between Sept 14 and 16, 2021, 420 participants were enrolled: 140 (33%) participants per group. Adverse reactions were reported by 26 (19%) participants in the low dose group and 33 (24%) in the high dose group within 14 days after the booster vaccination, significantly less than the 54 (39%) participants in the CoronaVac group (p<0·0001). The low dose group had a serum NAb GMT of 744·4 (95% CI 520·1-1065·6) and the high dose group had a GMT of 714·1 (479·4-1063·7) 14 days after booster dose, significantly higher than the GMT in the CoronaVac group (78·5 [60·5-101·7]; p<0·0001). INTERPRETATION: We found that a heterologous booster vaccine with an orally administered aerosolised Ad5-nCoV is safe and highly immunogenic in adults who have previously received two doses of CoronaVac as the primary series vaccination. FUNDING: National Natural Science Foundation of China and Jiangsu Provincial Key Research and Development Program.

Real-time reverse transcription-polymerase chain reaction assay panel for the detection of severe acute respiratory syndrome coronavirus 2 and its variants.

BACKGROUND: With the ongoing worldwide coronavirus disease 2019 (COVID-19) pandemic, an increasing number of viral variants are being identified, which poses a challenge for nucleic acid-based diagnostic tests. Rapid tests, such as real-time reverse transcription-polymerase chain reaction (rRT-PCR), play an important role in monitoring COVID-19 infection and controlling its spread. However, the changes in the genotypes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may result in decreased sensitivity of the rRT-PCR assay and it is necessary to monitor the mutations in primers and probes of SARS-CoV-2 detection over time. METHODS: We developed two rRT-PCR assays to detect the RNA-dependent RNA polymerase (RdRp) and nucleocapsid (N) genes of SARS-CoV-2. We evaluated these assays together with our previously published assays targeting the ORF1ab and N genes for the detection and confirmation of SARS-CoV-2 and its variants of concern (VOCs). In addition, we also developed two rRT-PCR assays (S484K and S501Y) targeting the spike gene, which when combined with the open reading frames (ORF)1ab assay, respectively, to form duplex rRT-PCR assays, were able to detect SARS-CoV-2 VOCs (lineages B.1.351 and B.1.1.7). RESULTS: Using a SARS-CoV-2 stock with predetermined genomic copies as a standard, the detection limit of both assays targeting RdRp and N was five copies/reaction. Furthermore, no cross-reactions with six others human CoVs (229E, OC43, NL63, HKU1, severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronavirus) were observed using these assays. In addition, the S484K and S501Y assays were combined with the ORF1ab assay, respectively. CONCLUSIONS: Four rRT-PCR assays (RdRp, N, S484K, and S501Y) were used to detect SARS-CoV-2 variants, and these assays were shown to be effective in screening for multiple virus strains.

Immunogenicity and safety of a severe acute respiratory syndrome coronavirus 2 inactivated vaccine in healthy adults: randomized, double-blind, and placebo-controlled phase 1 and phase 2 clinical trials.

BACKGROUND: The significant morbidity and mortality resulted from the infection of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) call for urgent development of effective and safe vaccines. We report the immunogenicity and safety of an inactivated SARS-CoV-2 vaccine, KCONVAC, in healthy adults. METHODS: Phase 1 and phase 2 randomized, double-blind, and placebo-controlled trials of KCONVAC were conducted in healthy Chinese adults aged 18 to 59 years. The participants in the phase 1 trial were randomized to receive two doses, one each on Days 0 and 14, of either KCONVAC (5 or 10 µg/dose) or placebo. The participants in the phase 2 trial were randomized to receive either KCONVAC (at 5 or 10 µg/dose) or placebo on Days 0 and 14 (0/14 regimen) or Days 0 and 28 (0/28 regimen). In the phase 1 trial, the primary safety endpoint was the proportion of participants experiencing adverse reactions/events within 28 days following the administration of each dose. In the phase 2 trial, the primary immunogenicity endpoints were neutralization antibody seroconversion and titer and anti-receptor-binding domain immunoglobulin G seroconversion at 28 days after the second dose. RESULTS: In the phase 1 trial, 60 participants were enrolled and received at least one dose of 5-µg vaccine (n = 24), 10-µg vaccine (n = 24), or placebo (n = 12). In the phase 2 trial, 500 participants were enrolled and received at least one dose of 5-µg vaccine (n = 100 for 0/14 or 0/28 regimens), 10-µg vaccine (n = 100 for each regimen), or placebo (n = 50 for each regimen). In the phase 1 trial, 13 (54%), 11 (46%), and seven (7/12) participants reported at least one adverse event (AE) after receiving 5-, 10-µg vaccine, or placebo, respectively. In the phase 2 trial, 16 (16%), 19 (19%), and nine (18%) 0/14-regimen participants reported at least one AE after receiving 5-, 10-µg vaccine, or placebo, respectively. Similar AE incidences were observed in the three 0/28-regimen treatment groups. No AEs with an intensity of grade 3+ were reported, expect for one vaccine-unrelated serious AE (foot fracture) reported in the phase 1 trial. KCONVAC induced significant antibody responses; 0/28 regimen showed a higher immune responses than that did 0/14 regimen after receiving two vaccine doses. CONCLUSIONS: Both doses of KCONVAC are well tolerated and able to induce robust immune responses in healthy adults. These results support testing 5-µg vaccine in the 0/28 regimen in an upcoming phase 3 efficacy trial. TRIAL REGISTRATION: http://www.chictr.org.cn/index.aspx (No. ChiCTR2000038804, http://www.chictr.org.cn/showproj.aspx?proj=62350; No. ChiCTR2000039462, http://www.chictr.org.cn/showproj.aspx?proj=63353).

Sr9Mg4.45(1)Bi9 and Sr9Mg4.42(1)Sb9: Mg-Containing Zintl Phases with Low Thermal Conductivity.

Zintl phases with nominal 9-4-9 formulas are very interesting for their potential applications as thermoelectric materials. However, the formation of such phases usually requires divalent transition metals, for example, Zn, Mn, and Cd, which are covalently bonded to the pnictogen atoms. In this report, for the first time, two Mg-containing compounds with such structures as Sr9Mg4.45(1)Bi9 and Sr9Mg4.42(1)Sb9 were synthesized and their structures were determined by the single-crystal X-ray diffraction method. Both title compounds crystallize in the orthorhombic space group Pnma and are isostructural with Ca9Mn4.41(1)Sb9, which features complex polyanion structures compared to the classical 9-4-9 phases. For Sr9Mg4.45(1)Bi9, its low thermal conductivity, combined with its high electrical conductivity and moderate Seebeck coefficient, leads to a decent figure of merit of 0.57 at 773 K, which obviously prevails in the unoptimized 9-4-9 phases. The discovery of such Mg-containing 9-4-9 phases is very significant, as the discovery not only enriches the structure map of the well-known 9-4-9 family but also provides very valuable thermoelectric candidates surely deserving of more in-depth investigation.

Germanium Crystalline Nanomaterials for Li-Ion Storage Prepared by Decomposing LiZnGe in Air.

Germanium nanomaterials are important for their potential applications in many fields. However, current synthetic technologies usually involve either high-cost explosive reagents or complicated facilities, which make the mass production especially challenging. In this report, a method was developed to synthesize nano-Ge materials conveniently, realized by decomposing LiZnGe in air at room temperature. The process is nontoxic, inexpensive, and, most of all, very suitable for large-scale production in combination with ball milling. The as-prepared Ge nanomaterials are crystalline whose structures can be flexibly tuned through the ball milling syntheses. As the lithium-ion battery anode, such Ge nanomaterials exhibited long-term cycle ability with high specific capacity as well as excellent rate performance. These results not only provided a very efficient way to prepare nano-Ge in lab or even promising industry production but also suggested a universal method in synthesizing the tetrels elemental nanomaterials.

Viral and Bacterial Etiology of Acute Febrile Respiratory Syndrome among Patients in Qinghai, China.

OBJECTIVE: This study was conducted to investigate the viral and bacterial etiology and epidemiology of patients with acute febrile respiratory syndrome (AFRS) in Qinghai using a commercial routine multiplex-ligation-nucleic acid amplification test (NAT)-based assay. METHODS: A total of 445 nasopharyngeal swabs specimens from patients with AFRS were analyzed using the RespiFinderSmart22kit (PathoFinder BV, Netherlands) and the LightCycler 480 real-time PCR system. RESULTS: Among the 225 (225/445, 51%) positive specimens, 329 positive pathogens were detected, including 298 (90.58%) viruses and 31 (9%) bacteria. The most commonly detected pathogens were influenza virus (IFV; 37.39%; 123/329), adenovirus (AdV; 17.02%; 56/329), human coronaviruses (HCoVs; 10.94%; 36/329), rhinovirus/enterovirus (RV/EV; 10.03%; 33/329), parainfluenza viruses (PIVs; 8.51%; 28/329), and Mycoplasma pneumoniae (M. pneu; 8.51%; 28/329), respectively. Among the co-infected cases (17.53%; 78/445), IFV/AdV and IFV/M. pneu were the most common co-infections. Most of the respiratory viruses were detected in summer and fall. CONCLUSION: In our study, IFV-A was the most common respiratory pathogen among 22 detected pathogens, followed by AdV, HCoV, RV/EV, PIV, and M. pneu. Bacteria appeared less frequently than viruses, and co-infection was the most common phenomenon among viral pathogens. Pathogens were distributed among different age groups and respiratory viruses were generally active in July, September, and November. Enhanced surveillance and early detection can be useful in the diagnosis, treatment, and prevention of AFRS, as well as for guiding the development of appropriate public health strategies.

Detection of six common human paramyxoviruses in patients with acute febrile respiratory symptoms using a novel multiplex real-time RT-PCR assay.

Human metapneumovirus (hMPV), respiratory syncytial virus type A (RSV-A), RSV-B, and human parainfluenza viruses 1, 2, and 3 (HPIV-1, HPIV-2, and HPIV-3) are common respiratory paramyxoviruses. Here, we developed a two-tube triplex one-step real-time reverse-transcription polymerase chain reaction (real-time RT-PCR) and evaluated its performance using clinical samples. The data showed that this novel assay was 100% consistent with the monoplex real-time RT-PCR assay (in-house), which was superior to the commercial routine multiplex-ligation-NAT-based assay. Meanwhile, the clinical nasopharyngeal swabs of 471 patients with the acute febrile respiratory syndrome (AFRS) were analyzed using the established method. The results showed that 52 (11.7%) cases were positive for paramyxovirus. Among them, HPIVs and RSV-A had the highest detection rate. The age and seasonal distribution of human paramyxovirus infection were analyzed. In conclusion, we developed a novel multiplex real-time RT-PCR assay for the rapid detection of six common human paramyxoviruses, which were dominant in patients with AFRS in Qinghai.

Structure, Magnetism, and Thermoelectric Properties of Magnesium-Containing Antimonide Zintl Phases Sr14MgSb11 and Eu14MgSb11.

New Mg-containing antimonide Zintl phases, Sr14MgSb11 and Eu14MgSb11, were synthesized from high-temperature solid-state reactions in Ta tubes at 1323 K. Their structures can be viewed as derived from the Ca14AlSb11 structure type, which adopt the tetragonal space group I41/acd (No. 142, Z = 8) with the cell parameters of a = 17.5691(14)/17.3442(11) Å and c = 23.399(4)/22.981(3) Å for the Sr- and Eu-containing compounds, respectively. The corresponding thermoelectric properties were probed, which demonstrated high potential of these compounds as new thermoelectrics for their very low thermal conductivity and moderate Seebeck coefficient. Magnetism studies and theoretical calculations were conducted as well to better understand the structure-and-property correlation of these materials.

Serological Study of An Imported Case of Middle East Respiratory Syndrome and His Close Contacts in China, 2015.

The first imported Middle East respiratory syndrome (MERS) case in China was identified in May 2015. We determined the kinetics of antibody (IgG and IgM) and neutralizing antibodies against MERS-coronavirus (MERS-CoV) in this case before discharge. Moreover, no seroconversion was found among 53 close contacts by anti-MERS IgG antibody enzyme-linked immunosorbent assay (ELISA) of paired serum samples. These findings suggest that neither community nor nosocomial transmission of MERS-CoV occurred in China.

Detection and Identification of Six Foodborne Bacteria by Two-tube Multiplex Real Time PCR and Melting Curve Analysis.

OBJECTIVE: This study is aimed to develop a two-tube melting curve-based multiplex real time PCR assay (MCMRT-PCR) for the simultaneous detection of six common foodborne pathogenic bacteria (diarrhoeagenic Escherichia coli, Salmonella, and Shigella in tube 1, Staphylococcus aureus, Vibrio parahaemolyticus, and Listeria monocytogenes in tube 2). METHODS: A two-tube MCMRT-PCR assay was performed on 7900HT Fast Real-Time PCR System (Applied Biosystems, USA). Amplification by PCR was optimized to obtain high efficiency. The sensitivity and specificity of assays were investigated. RESULTS: The detection limit of optimized MCMRT-PCR assay was 3.9×102 CFU/mL for S. aureus, 4.4×102 CFU/mL for L. monocytogenes, 3.0×102 CFU/mL for Salmonella, 2.5×102 CFU/mL for Shigella, 2.1×102 CFU/mL for V. parahaemolyticus, and 1.2×102 CFU/mL for E. coli. The feasibility of MCMRT-PCR was further evaluated using artificially contaminated milk, the sensitivity was at the level of 105 CFU/mL. CONCLUSION: A two-tube MCMRT-PCR assay using six primer sets was developed for detection of multiple pathogens. Our findings demonstrates that the proposed two-tube assay is reliable, useful and rapid for simultaneous detection of six foodborne pathogenic bacteria with an intended application in provincial Centers for Diseases Control and Prevention (CDC).

[Research progress in functions of coronavirus accessory genes].

In addition to the structural genes of the coronavirus genome, S, E, M, and N, there are several additional genes called "group-specific or accessory genes". Their gene products are designated as "accessory proteins", as reports to date make it clear that these proteins are not essential for virus replication in vitro. Nevertheless, many of these genes are still maintained in the virus genome under selective pressure, suggesting that they might play a very important role in the survival of the virus in the natural environment of the infected host. This review will summarize the research progress in the functions of coronavirus accessory genes.

[Calcineurin subunit B is not an effective adjuvant when combined with a novel HBV protein particle vaccine].

To compare different adjuvant formulation and explore the impact of Calcineurin B subunit(CnB) as adjuvant with a novel HBV protein particle (HBSS1) vaccine in mice, female C57BL/6 mice were immunized HBSS1 with Al(OH)3 only, or a normal dose (5 µg) CnB only, or (CnB+ Al(OH)3) mixture as the adjuvant. All immunized groups were primed twice at 4-week intervals; followed by boosting with recombinant adenoviral based HBV vaccine(rAdSS1) at 10-week intervals. We detected the antigen specific humoral response in mice, including total IgG antibody and IgG subtyping. Then, we characterized the specific cell-mediated immune (CMI) response by detection of γ-interferon secreting splenocytes after stimulaton with S or PreS1 peptide pools. No enhancement of immunity was found among the mice with 5 µg of CnB alone or combined with Al(OH), adjuvanted vaccine,which could not induce higher level of anti-PreS1 and anti-S antibodies and CMI than that of HBSS1 alone or Al(OH)3 adjuvanted vaccines. We concluded that CnB is not an effective adjuvant for a novel HBV subunit vaccine.

[The high expression of HPV31 and 52 L2 fusion protein in E. coli and detection of its immunogenicity].

OBJECTIVE: To express HPV31 and 52 L2 fusion protein and detect its immunogenicity. METHODS: According to the amino acid sequences of HPV31 and 52 L2 11-200AA published in the GenBank database, weartificially synthesized the HPV31 and 52 L2 fusion gene which was optimized according to Escherichia coli codon usage and encodes 11-200 amino acid of HPV31 and HPV52 L2, then cloned it into pET-9a vector. The HPV31 and 52 L2 fusion protein was expressed in Prokaryotic expression system and the mice were immunized with the fusion protein after purification. The immunogenicity was characterized in vaccinated mice. RESULTS: HPV31 and 52 L2 fusion protein was highly expressed in E. coli, the amount of fusion protein is nearly 20% of the total bacterial protein. The purified fusion protein with aluminum adjuvant could induce specific high titer of IgG antibodies detected by ELISA, and also induce the neutralizing antibodies against pseudovirus of HPV31 and HPV52 and cross-neutralizing antibodies against pseudovirus of HPV45, 58, 16, 18. CONCLUSION: HPV31 and 52 L2 fusion protein could induce neutralizing and cross-neutralizing antibodies against HPV pseudovirus. It provides laboratory basis for development of HPV L2 protein vaccine.

[Detection of human parvovirus B19, human bocavirus and human parvovirus 4 infections in blood samples among 95 patients with liver disease in Nanjing by nested PCR].

OBJECTIVE: To analyze the infection of human parvovirus B19, human bocavirus (HBoV) and human parvovirus 4 (PARV4) in blood samples among patients with liver disease in Nanjing by molecular detection. METHODS: Nested PCR assays were designed and validated to detect B19, HBoV and PARV4, respectively. The assays were used to screen three parvoviruses in blood samples from 95 patients with different liver disease in Nanjing. The parvovirus infection was analyzed statistically. RESULTS: The detection limits were 10 copies of genomic DNA equivalents per reaction for each assays and the good specificity were observed. The frequency of B19 and HBoV were 2/95 (2.1%) and 9/95 (9.5%) in blood samples respectively. No PARV4 was detected. HBoV was detected in 3/5 patients with drug-induced hepatitis. CONCLUSION: Both B19 and HBoV infection were detected in blood from patients with liver disease.

[Prokaryotic expression and characterization of two recombinant receptor-binding domain(RBD) proteins of human coronavirus NL63(HcoV-NL63)].

The receptor-binding domain(RBD) protein of HCoV-NL63 is a major target in the development of diagnostic assay and vaccine, it has a pivotal role in receptor attachment, viral entry and membrane fusion. In this study, we prepared 2 purified recombinant HCoV-NL63 RBD proteins using in E. coli system and identified the proteins by Western blotting. We first optimized codon and synthesized the RL (232-684aa)coding gene, then amplified the RL or RS(476-616aa) coding gene via PCR using different primers . The RL or RS coding gene was cloned into the pM48 expression vector fused with TrxA tag. The RBD (RL and RS) of HCoV-NL63 were expressed majorly as inclusion body when expressed in E. coli BL21pLys S under different conditions. The expressed products were purified by affinity chromatography then analyzed by SDS-PAGE and Western blotting. Our results showed that the recombinant RBD proteins were maximally expressed at 37 degrees C with 0. 8mM IPTG induction for 4h. RL or RS protein with 95 % purity was obtained and reacted positively with anti-sera from mice immunized with the recombinant vaccinia virus (Tiantan strain) in which HCoV-NL63 RL or RS protein was expressed. In conclusion, the purified recombinant RBD proteins(RL and RS)derived from E. coli were first prepared in China and they might provide a basis for further exploring biological role and vaccine development of HCoV-NL63.

[The establishment of a new resequencing pathogen microarray-based assay for detecting unexplained respiratory tract infections].

Resequencing Pathogen Microarray (RPM) is a new pathogen detection and identification technology based on DNA microarray. In order to apply RPM in the detection of unexplained infection and as a result, to improve the emergency response capacity, a new RPM-based respiratory pathogens detection assay was developed to simultaneously detect 19 common respiratory viruses, 9 influenza A viruses (Flu A),11 human rhinoviruses(HRV), 28 enteroviruses and 18 rare respiratory viruses. The specificity of multiplex system was examined by confirmed positive specimens for 16 common respiratory virus. The sensi-tivity was evaluated by serial ten-fold dilutions of plasmids or in vitro-transcribed RNA. RPM could detect and differentiate 16 virus types/subtypes at 10 - 1 000 copies/reaction level. Nucleic acids of 8 throat swabs with unexplained respiratory tract infections were pooled and detected by the new assay. The RPM result was verified by common PCR followed by sequencing as well as PLEX-ID (Abbott). Except for a false-positive of PIV1, no difference among the three assays was found. These results indicate the assay based on the new RPM is a highly sensitive, high throughput test for the detection of respiratory virus infections, which is significant for the management of emergent and epidemic infectious disease.

[Advances in recently identified coronaviruses].

Coronaviruses are a large family of viruses which include viruses that cause the common cold and severe acute respiratory syndrome (SARS) in humans and other diseases in animals. There are considerable genetic diversities within coronaviruses due to their wide rang hosts and their special gene replication and transcription mechanisms. During this process, gene recombinations often occur, resulting in novel subtype or coronavirus emerge constantly. Of note are SARS-like-CoVs and novel HCoV-EMC identified in 2012. This minireview summarized major advances of recently identified coronaviruses, focusing on the genome structures and interspecies jumping mechanism of coronavirus.

[Quasispecies sequence analyses of envelope protein E1/E2 coding genes from four Chinese HCV patients and identification of a novel insertion mutation of HCV].

This paper investigated the envelope protein E1/E2 quasispecies genetic characterization of 4 HCV positive sera (Genotype 1b: 274, 366, 383; Genotype 2a: 283) in China. Nucleotide acid was extracted and glycoprotein E1/E2 (191-764aa) coding genes were obtained by RT-PCR, positive clones were randomly selected for sequencing. The phylogenetic relationships and the homology of nucleotide and amino acid were analyzed based on E1/E2 coding genes, and some vital functional regions of E1/E2 were characterized. A total of 43 sequences (274: 10; 283: 12; 366: 13; 383: 8) were obtained showing high genetic heterogeneity in HVR1 and HVR2 regions, while sequences of the neutralizing epitopes, transmembrane domain I, II and N-terminal ectodomain were comparatively conservative. Single base (C) insertion mutation at nt1279 ( E1 region, aa313), resulting in a mutated E1 coding protein (beginning at aa 313) and interruption at N terminus (aa 398) of HVR1 region of E2, was dominant quasispecies sequence(11/12) found in serum 283 . This is the first report on E1/E2 quasispecies in Chinese HCV patients and this novel pattern of insertion mutation provides important information for further study on HCV pathogenesis and immune evasion.