Due to immature development of the immune system, preterm infants are at increased risk of infections from vaccine-preventable diseases. But at the same time, premature vaccination may not induce a good immune response because of the incomplete development of the neonatal immune system, and may cause serious adverse reactions risk due to the poor immune tolerance, thus vaccination of preterm infants at the appropriate time is the key to reducing the risk of infectious disease and obtaining vaccine protection. At present, it is generally recommended that the gestational age and birth weight should be considered in the vaccination of preterm infants. The timing, type and even the immunization schedule of the vaccine should be differ from that of the full term infants. However, there is a lack of research results and data on immunization program in preterm infants in China, and there is still no provided universal guidelines for their vaccine immunization. This article aims to summarize the guidelines and clinical trials of vaccination of preterm infants in foreign countries, and to provide reference for the formulation and implementation of immunization strategies for preterm infants in China.

Objective To evaluate anti-HEV IgG and IgM diagnostic kits with sera from convalescent hepatitis E patients and to establish the quantification method of detecting anti-HEV lgG.Methods Detect 42 convalescent serum samples of over 6 months after onset of hepatitis E patients from Jiangsu province with anti-HEV IgM and IgG diagnostic kits. Select and mix the anti-HEV IgG positive sera which were confirmed by Western blot with ORF2 and ORF3 antigen. The mixed serum was calibrated with a WHO anti-HEV Ig standard. A series quantitative linear standard was made for quantitative detection of anti-HEV IgG in hepatitis E vaccine clinical trials phase Ⅲ. Results The positive rates of the anti-HEV IgG di-agnose kits of G, K, MP, Wantai were 71.4%, 78.6%, 92.9% and 100% respectively. The positive rates of G was lower than that of MP (χ~2 = 5.19, P<0.05) and obviously lower than Wantai (χ~2 = 11.76,P<0.01). The positive rates of K was also obviously lower than that of Wantai (χ~2 =7.96, P <0.01).The positive rates of the anti-HEV IgM diagnose kits of MP, G, X, Wantai, K were 21.4%, 7.1%,21.4%, 64.3%, 78.6% respectively. The positive rate of both K and Wantai were obviously higher than that of MP(χ~2 = 15.75 ,P<0.01 ; X2 = 27.43 ,P< 0.01). With the Western blot confirmation test, 30 and 18 sera were reactive to ORF2 and ORF3 antigen separately. The anti-HEV IgG concentration of HEV-D01 mixed by 13 samples was 57.94 U/ml by the calibration. Prepare seven 1.5-fold dilution series of quantita-tive linear standard for HEV vaccine clinical trials phase Ⅲ, concentration range from 0.077 to 0.877 U/ml. The quantitive values of high, medium and low concentrations quality control samples lay in the range of average ± 2s, and the CV of quantitative values were 16%, 16%, 12% respectively. Conclusion The quality of different anti-HEY IgM and IgG diagnose kits were different. This study had set up a set of anti-HEV IgG linear quantitative standard, which fit for detecting anti-HEV IgG antibodies quantitatively in HEVvaccine clinical trial phase Ⅲ.

Original antigenic sin may exist in the influenza virus infection or vaccination, which possibly reduces the protective efficacy in repeated influenza vaccination. This paper reviews the literature on the original antigenic sin and its influence in influenza vaccination, and interprets the possible mechanism of this phenomenon from the three aspects of influenza virus structure, humoral immunity and cellular immunity. A large number of studies have shown that original antigen sin has a negative impact on influenza vaccination, but the evidence disproveing this phenomenon also exist, so multi?center large?scale clinical trials should be conducted to provide evidence?based basis for reaearching whether original antigen sin exists and its effects. in order to provide reference for the development and update of noval influenza vaccines and its formulation of immunization strategies.

Original antigenic sin may exist in the influenza virus infection or vaccination, which possibly reduces the protective efficacy in repeated influenza vaccination. This paper reviews the literature on the original antigenic sin and its influence in influenza vaccination, and interprets the possible mechanism of this phenomenon from the three aspects of influenza virus structure, humoral immunity and cellular immunity. A large number of studies have shown that original antigen sin has a negative impact on influenza vaccination, but the evidence disproveing this phenomenon also exist, so multi?center large?scale clinical trials should be conducted to provide evidence?based basis for reaearching whether original antigen sin exists and its effects. in order to provide reference for the development and update of noval influenza vaccines and its formulation of immunization strategies.

Objective To evaluate the practicability of using CRISPR/Cas9 genome editing tech-nology for inhibition of hepatitis B virus ( HBV) replication. Methods Two sgRNA targeting sites were de-signed for the S region of HBV genome. The CRISPR/Cas9 expression plasmids specific for HBV were con-structed and then transfected into a cell line expressing HBV genome(HepG2-N10). The cytotoxicity of cells transfected with different expression plasmids were detected by MTT assay. The levels of hepatitis B surface antigen ( HBsAg ) were determined by using chemiluminescent immunoassay ( CLIA ) . The expression of HBV at mRNA level was analyzed by quantitative real-time PCR ( qRT-PCR) . The qPCR was performed for the detection of extracellular and intracellular HBV DNA. The next-generation sequencing ( NGS) Illumina MiSeq Platform was used to analyze HBV genome editing. Results No significant cytotoxic effects were de-tected in HepG2-N10 cells transfected with different expression plasmids. Compared with the cells carrying pCas-Guide-GFP-Scramble, the levels of HBsAg in the supernatants of transfected cell culture harboring pCas-Guide-GFP-G1 and pCas-Guide-GFP-G2 were decreased by 24. 2% (P<0. 05) and 16. 9% (P>0. 05), respectively. The levels of HBsAg in cells transfected with pCas-Guide-GFP-G1 and pCas-Guide-GFP-G2 were respectively decreased by 16. 4% (P>0. 05) and 32. 1% (P>0. 05) as compared with that of pCas-Guide-GFP-Scramble transfected group. The expression of HBV at mRNA level was inhibited as indica-ted by the results of qRT-PCR. Moreover, the levels of extracellular HBV DNA were respectively suppressed by 23% (P>0. 05) and 35% (P<0. 05), and the levels of intracellular HBV DNA were respectively sup-pressed by 7. 2% (P>0. 05) and 18% (P>0. 05). Different types of insertion/deletion mutation were de-tected in HBV genome by high-throughput sequencing. Conclusion HBV-specific CRISPR/Cas9 system could inhibit the expression of HBV gene and the replication of virus. Therefore, the CRISPR/Cas9 genome editing technology might be used as a potential tool for the treatment of persistent HBV infection.

Objective To evaluate the diagnostic value of detection of IgM antibodies to EV71-infection patients,and compared characterisation of RT-PCR,IgM capture ELISA and neutralization test.Methods Virus RNA,neutralization titer and IgM antibody in 115 EV71-infection patients were detected by EV71 real-time RT-PCR kit( EV71-PCR kit),neutralization test,and EV71 IgM-capture ELISA kit (EV71-IgM kit),respectively.Results Using EV71-IgM kit,the detection rate was 80.9％ (93/115,95％ CI:72.5-87.6) among the 115 EV71-infection patients,and was 2.6％ among the 228 healthy children.Simultaneously,sera collected after 1-2 day of disease onset showed an IgM positivity of 70.4％ (38/ 54).The positive rate of EV71-PCR among these patients was 82.6％ (95/115,95％ CI:74.4-89.0),so there was no statistically significant differences between it and EV71-IgM kit.In addition,the detection rate in EV71-infection patients could increase to 92.2％ by combined detection of EV71-PCR and EV71-IgM kit.Conclusion EV71-IgM kit was a rapid and valuable way for the early diagnosis of EV71 infection,and could significantly improve detection rate for EV71 infection by combining with EV71-PCR kit.

Intestinal microbiota plays an important role in the development of immune system,es-pecially in the formation of immune response. Immune response to vaccination varies with region and popula-tion,which may be related to the differences in intestinal microbiota. This review focused on the correlation between intestinal microbiota and immune response to vaccination in order to find a new way to enhance vac-cine-induced immune response. It was revealed that intestinal microbiota might be involved in the immune responses to vaccines against rotavirus, typhoid and polio. Although probiotics, prebiotics and synbiotics could not significantly enhance vaccine-induced immune response,they might have a beneficial effect on vac-cine by regulating intestinal microbiota.

Maternal immunization is an immune strategy that protects both mothers and early?life infants from disease by the vaccination of pregnant women. The effect of maternal immunization is influenced by the types of vaccines, the timing of vaccination, the subtypes of antibodies induced by vaccines, and the health status of mothers themselves. Inactivated influenza vaccination during pregnancy and DPT vaccination during the third trimester of pregnancy have been widely used in the world, while Hepatitis B vaccine, pneumococcal and meningococcal vaccines also show good efficacy and safety in pregnant women. This article reviews the research progress of Maternal Immunization in order to provide a reference for Maternal Immunization planning and policymaking in China.

Effectiveness of seasonal influenza vaccines varies greatly during the different flu seasons. Although the WHO assesses and updates influenza vaccine strains every year, the effectiveness of vaccine is sometimes not good. This review explores the various factors that influencing influenza vaccine effects in order to improve the effectiveness of influenza vaccines and provide a scientific basis for influenza vaccination. The results reveal that the degree of matching between epidemic strains and vaccine strains, pre-exposure (natural infection, vaccination), age, and immune status could all affect the vaccine effectiveness.

Maternal immunization is an immune strategy that protects both mothers and early?life infants from disease by the vaccination of pregnant women. The effect of maternal immunization is influenced by the types of vaccines, the timing of vaccination, the subtypes of antibodies induced by vaccines, and the health status of mothers themselves. Inactivated influenza vaccination during pregnancy and DPT vaccination during the third trimester of pregnancy have been widely used in the world, while Hepatitis B vaccine, pneumococcal and meningococcal vaccines also show good efficacy and safety in pregnant women. This article reviews the research progress of Maternal Immunization in order to provide a reference for Maternal Immunization planning and policymaking in China.