Prevention and Nursing of Adverse Reactions of Novel Coronavirus Inactivated Vaccine (Vero Cells)

Objective:To discuss and analyze the causes of adverse reactions caused by the inactivated novel coronavirus vaccine(Vero cells),and to propose methods of prevention and care.Methods:A questionnaire was used to randomly select 229 adults who were vaccinated with the inactivated novel coronavirus vaccine(Vero cells)at Xi’an People’s Hospital(Xi’an Fourth Hospital).The adverse reactions were statistically analyzed.Results:Among the 229 adults vaccinated with the inactivated novel coronavirus vaccine(Vero cells),30 experienced vaccination reactions.The main reaction was local induration at the inoculation site,and dizziness was the primary systemic symptom.Conclusion:To reduce the incidence of adverse reactions to the inactivated novel coronavirus vaccine(Vero cells),it is necessary to effectively evaluate the health status of adults before vaccination,select the correct vaccination site,and strictly implement the rules of 3-inspections,7-checks,and 1-verification.Standardizing the operation process and providing thorough health education after vaccination can effectively reduce the occurrence of adverse reactions.

A Case of Investigation and Diagnosis of Immune Thrombocytopenic Purpura After Vaccination of COVID-19 Inactivated Vaccine

Objective:Analyze the relationship between inoculating one case of the COVID-19 inactivated vaccine(Vero cell)and immune thrombocytopenic purpura to provide a reference for the standardized handling of adverse events following immunization.Methods:According to the"National Monitoring Program for Suspected Adverse Reactions to Vaccinations,"an on-site investigation,data collection and analysis,expert group diagnosis,and medical association assessment were conducted on a case of immune thrombocytopenic purpura in District A of Chongqing after vaccination with the inactivated COVID-19 vaccine.The assessment report was delivered to the three relevant parties,the case was reviewed,and the experience was summarized.Results:The investigation and diagnosis by the district-level vaccination abnormal reaction expert group concluded that the disease that occurred after vaccination with the COVID-19 inactivated vaccine was secondary immune thrombocytopenic purpura,an abnormal reaction to the vaccination.The medical damage was classified as Level II Grade B.The vaccine production enterprise raised objections to this conclusion.After re-assessment by the municipal-level medical association,the conclusion was consistent with that of the district-level medical association.The vaccine production enterprise did not raise any further objections.Conclusion:Through active collaboration among district and municipal-level medical associations,disease control institutions,and vaccination units,the recipients have been promptly and effectively treated,providing financial support for their subsequent treatment and safeguarding their rights.The investigation and disposal procedures for adverse events following immunization in Chongqing are clear,and the mechanism is sound.It is necessary to continue strengthening the monitoring of adverse events following immunization according to the existing plan and to ensure timely and standardized handling.Simultaneously,it is crucial to strengthen vaccine management and vaccination management.

Immuno-Protective Efficiency of the Bivalent Inactivated Vaccine Against Vibrio scophthalmi and Aeromonas salmonicida Infections in Turbot(Scophthalmus maximus L.)

Vibrio scophthalmi and Aeromonas salmonicida can cause high turbot mortality and huge economic losses.Presently,vaccination is the most promising method for preventing communicable diseases.In this study,we used formalin to kill V.scophthalmi and A.salmonicida cells,and mixed with the mineralized oil adjuvant(Montanide^(TM)ISA 763 AVG)to prepare the bivalent inactivated vaccine.The results showed that turbot inoculated with the bivalent inactivated vaccine exhibited strong tolerance to the infection of V.scophthalmi and A.salmonicida,and no obvious clinical symptoms and pathological changes were observed.The activities of enzymes lysozyme,acid phosphatase and complement C3 had significantly increased after the vaccination.The antibody titer response of vaccinated turbot was greatly boosted,which was positively connected with the immunological impact according to ELISA results.Simultaneously,the expression levels of immune-related genes such as MHC-IIα,MHC-IIβ,CD4,CD8,TNF-αand IL^(-1)βwere up-regulated,demonstrating that it might stimulate humoral and cellular immunological response in turbot.These findings highlight the potential of the bivalent inactivated vaccine for controlling V.scophthalmi and A.salmonicida infections in turbot.

Development of a Multivalent Inactivated Vaccine against Pathogenic Escherichia coli Infection in Forest Musk Deer

A multivalent inactivated Escherichia coli vaccine for forest musk deer by using serotypes O4,O26,and O139 with Al（OH）3 adjuvant was prepared.The vaccine did not cause any adverse reactions in forest musk deer.The immunogenic effects of the vaccine were experimentally investigated in pregnant and young forest musk deer.The serum antibody titers of pregnant and young forest musk deer were determined by performing the micro-agglutination test.The serum antibody titers of pregnant forest musk deer were more stable from 35th to 68th d after the third vaccination,and the serum antibody titers of four pregnant forest musk deer were maintained 25,25,25,and 24 on 68th d after the third vaccination.Young forest musk deer showed serum antibody titers which were obtained due to nursing.Young forest musk deer were administered the first intramuscular vaccine injection at an age of approximately 60 days due to a fall in maternal antibody titers.The serum antibody titers of young forest musk deer were higher after the third vaccination and maintained at approximately the same level until they were 137 days old.The maternal antibodies and the antibodies produced by young forest musk deer could be helpful for protecting the young musk deer from the infections of pathogenic Escherichia coli strains（serotypes O4,O26,and O139）for 137 days after birth（during the nursing period and the period when the forest musk deer were susceptible to diseases）.

Immune response to inactivated bacterial vector carrying the recombinant K39 antigen of Leishmania infantum in mice

Objective:To evaluate the immunological response elicited by an inactivated bacterial vector carrying the K39 antigen of Leishmania infantum,and a purified antigen.Methods:Mice were subjected to the following treatments:(1)Purified recombinant K39(rK39)protein at a 20μg dose with complete Freund’s adjuvant;(2)Inactivated Escherichia coli(BL21 DE3)carrying the K39 protein at an equivalent total protein content of 200μg;(3)Inactivated bacteria lacking the K39 protein;(4)Non-immunized control animals.Serological monitoring was performed.All groups were challenged by intraperitoneal injection of 10^(7) Leishmania infantum promastigotes.After euthanasia,the liver and spleen were collected to analyze the levels of TNF,IFN-γ,IL-12,IL-4,and IL-10.Results:Mice immunized with purified rK39 or the inactivated bacterial vector carrying the K39 antigen of Leishmania infantum showed a long-lasting immune response with high levels of polyclonal antibodies specifically recognizing the recombinant proteins.The IgG1 subclass was the predominant immunoglobulin;however,the induction of IgG2a and the profile of cytokines produced were indicative of the induction of a mixed-type response.Conclusions:The inactivated bacterial vector carrying the K39 antigen,as well as the purified antigen can induce a long-lasting immune response in immunized mice,predominantly favouring a Th2 profile response.

Preparation of Purified and Inactivated HP-PRRS Vaccine

[Objective] The aim of this study was to improve the purification and protective potency of HP-PRRS inactivated vaccine. [Method] HP-PRRS virus that had been multiplied inside Marc-145 cells was collected and concentrated 50 times and then inactivated. Complete virions were separated and collected by chromatography with Sepharose 4 Fast Flow. Oil adjuvant was added to prepare purified inactivated vaccine. [Result] Viral protein was separated from other proteins by purification and the viral protein contents ranged from 76.7% to 82.4%, and 96% of the expected serum proteins were removed. Protective potency of purified vaccine was above 4/5 and positive conversion rate of antibody was over 86%, both higher than that of unpurified vaccine. The differences were significant. [Conclusion] The experiment il-lustrated that the immune efficacy of vaccine can be enhanced through concentrat- ing and purifying, while the non-viral protein can be removed, so that allergic reaction and stress response cadsed by vaccine inoculation can be avoided.

Gas chromatography-mass spectrometry method for determination ofβ-propiolactone in human inactivated rabies vaccine and its hydrolysis analysis

A simple method was established for the determination of β-propiolactone(BPL) in human inactivated rabies vaccine by gas chromatography-mass spectrometry(GC-MS). The determination was performed on an Agilent HP-INNOWAX(30 m ? 0.32 mm i.d., 0.25 mm) capillary column at the temperature of 80 °C.Electrospray ionization(ESI) was used by selective ion detection at m/z 42. The temperature for ESI source and inlet was set at 230 °C and 200 °C, respectively. Helium was used as the carrier gas at a flow rate of 25.1 m L/min. The total run time was 8 min. Acetonitrile and other components in the sample did not interfere with the determination of BPL. The results showed good linearity of BPL in the range of0.50–10.01 μg/mL, with the limit of detection and the limit of quantification of 0.015 μg/mL and0.050 μg/mL, respectively. Satisfactory precision was achieved for the current developed method. The method was applied to detect 6 batches of vaccine samples, and the results indicated that the target analyte BPL was present in three batches of unpurified samples, but was not detected in the purified samples, indicating the test samples were qualified. The established method was proved to be simple,versatile and sensitive, which can meet the requirements of quality control of BPL in human inactivated rabies vaccine.

Porcine Interleukin-2 Expression in Insect Cells and Its Enhancement of Pig Immunity to Swine Influenza Virus Inactivated Vaccine

Mature porcine interleukin-2 （pIL-2） gene was amplified by PCR from the plasmid pGEM-T-pIL2 and cloned into the baculovirus pFastBacTM Dual vector of the Bac-to-Bac baculovirus expression system under the control of the PH promoter. Recombinant plL-2 （rpIL-2） expressed in Sf9 insect cells was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunofluorescence assay. Western blot analysis confirmed that the rpIL-2 protein had a molecular mass of 20 kDa, which was larger than the molecular mass of the mature protein predicted based on its peptide sequence. The rpIL-2 protein induced in vitro proliferation of ConA-stimulated porcine splenocytes and enhanced in vivo protective immune responses induced by vaccinating the pigs with inactivated oil emulsion vaccine against swine influenza virus. The results showed that the rpIL-2 expressed in Sf9 insect cells has immunoenhancement effects; the finding lays the foundation for the preparation of a specific recombinant IL-2 protein and the development of a novel immune adjuvant of vaccines against various infectious porcine pathogens to increase the immunoprotective efficacy of vaccines.

Isolation and characterization of a new candidate human inactivated rotavirus vaccine strain from hospitalized children in Yunnan,China:2010-2013

AIM To determine the distribution of rotavirus VP7 gene in hospitalized children in Yunnan, China. METHODS A total of 366 stool specimens were collected from hospitalized children in hospitals in Yunnan Province from September 2010 to December 2013. The genomic RNA electropherotypes and the G genotypes of the rotaviruses were determined. A phylogenetic analysis of the VP7 gene was performed. Rotavirus isolation was performed, and characterized by plaque, minimum essential medium, and all genes sequence analysis. Quantification of antibodies for inactivated vaccine prepared with ZTR-68 was examined by enzyme-linked immunosorbent assay and microneutralization assay.RESULTS Group A human rotavirus was detected in 177 of 366(48.4%) stool samples using a colloidal gold device assay. The temporal distribution of rotavirus cases showed significant correlation with the mean air temperature. Rotaviruses were isolated from 13% of the rotavirus-positive samples. The predominant genotype was G1(43.5%), followed by G3(21.7%), G9(17.4%), G2(4.3%), G4(8.7%), and mixed(4.3%) among a total of 23 rotavirus isolates. A rotavirus strain was isolated from a rotavirus-positive stool sample of a 4-month-old child in The First People's Hospital of Zhaotong(2010) for use as a candidate human inactivated rotavirus vaccine strain and for further research, and was designated ZTR-68. The genotype of 11 gene segments of strain ZTR-68(RVA/Human-wt/CHN/ZTR-68/2010/G1P[8]) was characterized. The genotype constellation of strain ZTR-68 was identified as G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. The VP7 and VP4 genotypes of strain ZTR-68 were similar to Wa-like strains.CONCLUSIONS A high prevalence of the G1, G2, and G3 genotypes was detected from 2010 to 2012. However, a dominant prevalence of the G9 genotype was identified as the cause of gastroenteritis in children in Yunnan, China, in 2013. A candidate human inactivated rotavirus vaccine strain, designated ZTR-68 was isolated, characterized, and showed immunogenicity. Our data will be useful for the future formulation and development of a vaccine in China.

Protective effect of inactivated hepatitis A vaccine against the outbreak of hepatitis A in an open rural community

AIM： To evaluate the protective effect of inactivated hepatitis A vaccine （Healive） against hepatitis A outbreak in an emergency vaccination campaign. METHODS： During an outbreak of hepatitis A in Honghe Town, Xiuzhou District, Jiaxing City, Zhejiang Province, two nonrandomized controlled trials were conducted in September 2006. The first trial was to vaccinate 108 anti-HAV negative individuals with close contacts of the patients from September with 1 dose of an inactivated hepatYds A vaccine, HeaUve. The control group comprised of 115 individuals with close contacts of the patients before September. The second trial was to vaccinate 3365 primary and secondary school students who volunteered to receive a dose of Healive and 2572 students who did not receive Healive serving as its controls. An epidemiological survey was conducted to evaluate the pmtectk, e efficacy of the vaccine. RESULTS： A total of 136 hepatitis A cases were reported during an outbreak that started in June, peaked in August and September, and ended after December of 2006. After a massive vaccination of school children in September, the number of cases declined significantly. No hepatitis A was detected in the 108 vaccinated individuals with dose contacts of patients, whereas 4 cases of hepatitis A were found in the controls. The infection rate of hepatitis A was not significantly different in the individuals with close contacts of patients whether or not they received the vaccine （P = 0.122）. No hepatitis A was detected in the 3365 students who received the vaccine, four cases of hepatitis A were found in the controls. The infection rate of students with or without vaccination was significantly diffeent in the students who received the vaccine （0/3365 vs 4/2572, P = 0.035）. The protective efficacy of the vaccine was 100%.CONCLUSION： Inactivated hepatitis A vaccine demonstrates a good protective effect against an outbreak of hepatitis A.

A Semi-quantitative Serological Method to Assess the Potency of Inactivated Rabies Vaccine for Veterinary Use

Potency is one of the most important indexes of inactivated vaccines.A number of methods have been established to assay the potency,of which the NIH test and single-dose mouse protection test are the "prescribed methods".Here,we report a method to semi-quantitatively assay the potency of an inactivated rabies vaccine,which uses fewer animals and takes less time to complete.Depending on the quality requirements of a vaccine(e.g.minimum potency),a rabies reference vaccine is,for example,diluted to the minimum potency,and 50 μL of the dilution is taken to inoculate 10 mice.The same amount of the test rabies vaccine is inoculated into another 10 mice.After two weeks,all mice are bled and serum samples are assayed for viral neutralizing antibody by the fluorescent antibody virus neutralization(FAVN) test.By comparing the median and interquartile range of antibody titers of the reference vaccine with those of the test vaccine,the test vaccine potency can be semi-quantitatively judged as to whether it is in accord with the required quality.The reliability of this method was also confirmed in dogs.The procedure can be recommended for batch potency testing during inactivated rabies vaccine production.

Development of an Inactivated Iridovirus Vaccine Against Turbot Viral Reddish Body Syndrome

Turbot(Scophthalmus maximus L.) reddish body iridovirus(TRBIV) was propagated in turbot fin cells(TF cells) and inactivated as the TRBIV vaccine with its protection efficiency evaluated in this study.TF cells were cultured in 10% bovine calf serum(BCS)-containing MEM medium(pH7.0) at 22℃,in which TRBIV propagated to a titer as high as 105.6 TCID50 mL-1.The TRBIV was inactivated with 0.1% formalin and formulated with 0.5% aluminum hydroxide.The inactivated vaccine caused neither cytopathogenic effect(CPE) on TF cells nor pathogenic effect on turbots.After being administered with the vaccine twice via muscle injection,the turbot developed high-tittered TRBIV neutralizing antibodies in a dose-dependent manner.The vaccine protected the turbot from dying with an immunoprotection rate of 83.3% as was determined via subcutaneous vaccination in the laboratory and 90.5% via bath vaccination in turbot farms,respectively.The inactivated vaccine was very immunogenic,efficiently preventing tur-bot from death.It holds the potential of being applied in aquaculture.

Adverse Effects of Inactivated Foot-and-Mouth Disease Vaccine—Possible Causes Analysis and Countermeasures

Foot-and-mouth disease (FMD) is an infectious and sometimes fatal viral disease that affects cloven-hoofed animals, and Chinese government adopts compulsory immunization measures for FMD. The adverse effects of FMD vaccine to pigs, cattle and goats have been reported increasingly frequent during the spring and autumn seasons when large numbers of farm livestock are vaccinated. The financial losses caused by vaccine adverse effects have been a serious concern for both farmers and primary prevention personnel. There are various causative factors reported to involve into adverse effect of FMD vaccine, including the inappropriate vaccine production, transportation and storage, livestock poor tolerance, and unqualified vaccinating manipulations. Symptomatic treatment and early drug prevention have a certain effect on the adverse effects. To analyze causes and propose countermeasures, in the current study possible reasons during the production and processing procedures of inactivated FMD vaccine were reviewed and corresponding countermeasures were recommended. The review may provide references for better use of vaccine to prevent FMD.

Human IgM and IgG Responses to an Inactivated SARS-CoV-2 Vaccine

Objective:The ongoing COVID-19 pandemic warrants accelerated efforts to test vaccine candidates.To explore the influencing factors on vaccine-induced effects,antibody responses to an inactivated SARS-CoV-2 vaccine in healthy individuals who were not previously infected by COVID-19 were assessed.Methods:All subjects aged 18-60 years who did not have SARS-CoV-2 infection at the time of screening from June 19,2021,to July 02,2021,were approached for inclusion.All participants received two doses of inactivated SARS-CoV-2 vaccine.Serum IgM and IgG antibodies were detected using a commercial kit after the second dose of vaccination.A positive result was defined as 10 AU/mL or more and a negative result as less than 10 AU/mL.This retrospective study included 97 infection-naive individuals(mean age 35.6 years;37.1%male,62.9%female).Results:The seropositive rates of IgM and IgG antibody responses elicited after the second dose of inactivated SARS-CoV-2 vaccine were 3.1%and 74.2%,respectively.IgG antibody levels were significantly higher than IgM levels(P<0.0001).Sex had no effect on IgM and IgG antibody response after the second dose.The mean anti-IgG level in older persons(≥42 years)was significantly lower than that of younger recipients.There was a significantly lower antibody level at>42 days compared to that at 0-20 days(P<0.05)and 21-31 days(P<0.05)after the second dose.Conclusion:IgG antibody response could be induced by inactivated SARS-CoV-2 vaccine in healthy individuals(>18 years),which can be influenced by age and detection time after the second dose of vaccination.

Comparative Immune Efficacy of Native Inactivated and Attenuated Vaccines for Porcine Reproductive and Respiratory Syndrome Virus over 2 Consecutive Years

The primary objective of this study was to evaluation the immune efficacy of native inactivated vaccine against porcine reproductive and respiratory syndrome virus. The experimental design included 60 gilts and 9 boars equal distribution in two farms free of antibody for PRRSV at the beginning of the experiment for two consecutive months. These gilts and boars were randomly assigned to three treatment groups equally designated as groupsⅠ～Ⅲ. GroupⅠwas inoculated intramuscularly with RespPRRSV/Repro vaccine. Group Ⅱ was inoculated intramuscularly with native multivalent inactivated vaccine. Group Ⅲ was sham-inoculated intramuscularly with saline as control. Gilts and boars were inoculated again at six months intervals during the consecutive 2 years. The neonatal piglets of three groups were inoculated the same vaccine as their parents one week before weaning (piglets were 25 days). Then antibody anti-PRRSV was detected in sera obtained from gilts, boars and piglets. Biological tissue samples were collected from the recently deceased or sacrificed pigs which presented with similar PRRS symptoms. Virus isolation and viral RNA using RT-nPCR were carried through in collected tissue samples, sera and semen. Productive performances of pigs were also evaluated in this project. The results showed all the indexes in groupⅡwere very similar to that of groupⅠexcept the virus isolation and viral RNA detection. Control group had more virus isolates and viral RNA detection than inoculated groups. The rate of piglets surviving, born dead and postnatal deaths and fattening differed significantly (P<(0.05)) between experiment groups and control. This was implied that pigs inoculated with native inactivated vaccine had the similarity immune efficacy to that of pigs inoculated attenuated vaccine. This is the first large-scale to evaluation the immune efficacy of native multivalent inactivated vaccine against PRRSV in field trial. Inoculating native inactivated multivalent vaccine is also an effective measure to prevent PRRS in Shanghai pig farms and this can reduce the risk of vaccine virus shedding because of inoculating the attenuated vaccine.

Studies on Immunological Effect and Immunological Mechanism Avian Encephalomyelitis Oil Emulsion Inactivated Vaccine

Oil emulsion inactivated vaccine was prepared by susceptible embryos, with different strains of AEV. Four groups of normal chickens of 2 - 7 days of age were given injections for immunization, respectively. Another group was used as control. This study was expected to evaluate the immunological effect and discuss the immunological mechanism by means of five different experiments, i.e. the agar-gel precipitin test, the isolation of lymphokine, the isolation, purification and analysis of blood serum IgG, embryo-susceptibility test, and clinical and pathological examination. The results of these experiments indicated that oil emulsion inactivated vaccine is safe and effective. The chickens were normal when inoculated with AE strong virus after immunity at 4 and 37 weeks. Immunological mechanism is that the humoral immunity played an important role and celluar immunity exists, but it is not important in the process of the resistance to AEV.

Effect of Viral Antigen Levels on the Serological Response and Efficiency of the Binary Ethylenimine-Inactivated Bluetongue Virus Serotype-16 Vaccine

Bluetongue (BT) is a serious hemorrhagic disease of ruminants caused by bluetongue virus (BTV). Inactive BTV vaccines have been successful in field trials in some areas, and inactivated vaccines are considered safer. However, information about the effect of the viral antigen level on the serological response and efficiency of the inactive BTV-16 vaccine is lacking. In the present study, the serological response and efficiency of the viral antigen concentration in the binary ethylenimine-inactivated Chinese BTV serotype-16 vaccine were investigated. The viral antigens in the viral suspension (VS) were quantified using a modified BTV AC-ELISA method. Four batches of vaccine containing 1, 5, 10, and 50 μg/ml of viral antigen were generated from the VS. Four groups of naive Chinese sheep were vaccinated with the different vaccine batches, and the serological response and vaccine efficiency were investigated before and after challenge infection. The vaccines containing 10 and 50 μg/ml of viral antigen induced significant ELISA and neutralizing antibody titers 14 days after vaccination, whereas the vaccines containing 1 and 5 μg/ml of viral antigen did not have these effects. A booster immunization at 21 days enhanced all groups’ antibody titers;however, the increased titer was related to the viral antigen level. In contrast to the serological response, the viral antigen level of the vaccines did not have a significant effect on the vaccine efficiency. With the exception of one sheep from the 5 μg/ml viral antigen group, all vaccinated sheep from the four antigen level groups showed strong resistance to infection based on their clinical symptoms, rectal temperatures and viremia. Collectively, these data suggested that viral antigen levels from 1 to 50 μg/ml had a significant effect on the serological response of the animals but a limited effect on the vaccine efficiency. The BTV-16 vaccine containing 1 μg/ml of viral antigen was sufficient to achieve high efficiency, but only the vaccines with more than 10 μg/ml of antigen induced a significant antibody response. To obtain a better serological response, we suggest the use of vaccines with more than 10 μg/ml of viral antigen. The findings in the study will be useful for BTV vaccine production.

Immune Effects of Porcine Interleukin-2,4 on Piglets Using as Immunopotentiator for PCV Inactivated Vaccine

[ Objective] To investigate the combined immunization of porcine circovirus 2 （PCV2） inactivated vaccine with PoIL-2,4. [ Methods] A total of 60 crossbred piglets were randomly divided into three groups, including the test group （ inoculation of 0.5 dose PCV2 inactivated vaccine with 0. 1 mL PoIL-2,4 at 14 and 28 day-old）, the positive control group （inoculation of 0.5 dose PCV2 inactivated vaccine） and the blank control group. [ Results ] The immune organ index, the lymphocyte transformation rates under different ages and the number of leukocytes and lymphocytes in peripheral blood increased significantly in test group, compared with control group. Moreover, the antibody and neutralizing antibody were also significantly higher in test group than that in control group. The clinical symptoms and pathological changes were not found, and the PC72 was not detected in serum and tissue after challenge test in test group, which indicated that the combined immunization of PCV2 inactivated vaccine with PoIL-2,4 significantly improved the lymphocyte transformation rate, effectively prevented the replication of PCV2 in organism, and enhanced the growth performance of piglets.

Preparation and Examination of Inactivated Emulsion Vaccine against Newcastle Disease, Infectious Bronchitis and H9 Subtype Avian Influenza

[ Objective] To prepare inactivated emulsion vaccine against Newcastle disease, infectious bronchitis and H9 subtype avian influenza. [ Method] Antigen fluid of Newcastle disease virus （NDV） La Sota strain, infectious bronchitis virus （IBV） M41 strain and HgN2 subtype avian in- fluenza virus （AIV） WD strain was prepared by propagation in chicken embryos, respectively. The antigen fluid was concentrated with FILTRON Cassette ultra-filtration system and inactivated by formalin. The antigen fluid of NDV, IBV and AIV was mixed at a volume ratio of 1：1：1. Then the mixture was emulsified by Span-80 and Tween-80 and added medical white oil as adjuvant. The sterility and physical characteristics of the prepared ND-IB-AI combined vaccine were detected. [ Result] The three batches of ND-IB-AI combined vaccine were germ-free, milky white, with water-in- oil pattern and with viscosity of 6.3 -6.8 s. The water and oil were not separated after rest at 37 ~C for 21 d or centrifugation. [ Conclusion] The three batches of ND-IB-AI combined vaccine were germ-free and reached the standard for physical characteristics of vaccines.

Modeling the Long-term Antibody Response and Duration of Immune Protection Induced by an Inactivated,Preservative-free Hepatitis A Vaccine(Healive)in Children

Objective Long-term seroprotection via the hepatitis A vaccine is essential for the prevention of disease from the hepatitis A virus(HAV).Due to documented difficulties during decade-long follow-ups after receiving vaccines,statistical-modeling approaches have been applied to predict the duration of immune protection.Methods Based on five-year follow-up data from a randomized positive-controlled trial among Chinese children(1–8 years old)following a 0,6 months vaccination schedule,a power-law model accounting for the kinetics of B-cell turnover,as well as a modified power-law model considering a memory-B-cell subpopulation,were fitted to predict the long-term immune responses induced by HAV vaccination(Healive or Havrix).Anti-HAV levels of each individual and seroconversion rates up to 30 years after vaccination were predicted.Results A total of 375 participants who completed the two-dose vaccination were included in the analysis.Both models predicted that,over a life-long period,participants vaccinated with Healive would have close but slightly higher antibody titers than those of participants vaccinated with Havrix.Additionally,consistent with previous studies,more than 90%of participants were predicted to maintain seroconversion for at least 30 years.Moreover,the modified power-law model predicted that the antibody titers would reach a plateau level after nearly 15 years post-vaccination.Conclusions Based on the results of our modeling,Healive may adequately induce long-term immune responses following a 0,6 months vaccination schedule in children via induction of memory B cells to provide stable and durable immune protection.