OBJECTIVETo describe the design and application of cluster randomized controlled method on typhoid Vi vaccine trial, and to assess the effect of implementation.

METHODSSimple size calculation of cluster-randomized trial was used to determine the sample size of the two groups and a vaccination campaign was conducted. The study group was given typhoid Vi vaccine and the control group was given meningococcal A vaccine.

RESULTSAccording to sample size calculation, a total sample of 96,121 participants was required and the study areas were divided into 108 clusters. In practice, 53 study clusters with 44,054 participants and 54 control clusters with 48,422 participants were stratified and matched according to size, location (urban or rural), characteristics (school, department, factory, demography) were randomized respectively. Confounding factors of two groups including age, sex, resident area, income, level of education were compared. It was found that the ratio of all confounding factors between the two groups were comparable and balanced.

CONCLUSIONConfounding factors can be better controlled between study group and the control group by applying cluster-randomized method on vaccine trail which enabled the intervention to be more scientifically evaluated; The implementation of cluster randomization trial was simple and easy to be accepted.

Adolescent ; Adult ; Child ; Child, Preschool ; China ; Cluster Analysis ; Female ; Humans ; Male ; Mass Vaccination ; organization & administration ; Middle Aged ; Polysaccharides, Bacterial ; immunology ; Typhoid Fever ; prevention & control ; Typhoid-Paratyphoid Vaccines ; immunology ; Vaccination

Salmonella Typhi capsular polysaccharide vaccines were encapsulated in the Micro-particles made from polyethylene glycol-poly-DL-lactide (PELA). BALB/c mouse were divided into three groups with 20 mice in each. Mouse were immunized respectively with controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines and Salmonella Typhi capsular polysaccharide vaccines by oral and subcutaneous administration. The mice blood and salvia were collected at the 2nd, 4th and 8th weeks respectively for the titrating of IgG and sIgA antibodies by RIA. At the 8th week, live typhoid bacteria were injected into the immunized mice for the calculation of the rate of immunization protection. The IgG titers of the controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines group were higher than those of the other groups(P < 0.05). The IgA titers of the low groups of controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines (oral and subcutaneous) were higher than those of the group of Salmonella Typhi capsular polysaccharide vaccines (P < 0.05). The immunization protection rates of the three groups were 40%, 100% and 60% respectively. The controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines possess the advantages of releasing slowly in vivo and persisting long time immunogenicity.
Administration, Oral ; Animals ; Delayed-Action Preparations ; Female ; Immunoglobulin A, Secretory ; analysis ; Immunoglobulin G ; blood ; Injections, Subcutaneous ; Mice ; Mice, Inbred BALB C ; Microspheres ; Polysaccharides, Bacterial ; administration & dosage ; immunology ; Typhoid-Paratyphoid Vaccines ; administration & dosage ; immunology ; Vaccination

OBJECTIVETo study the regulating effects of a novel CpG oligodeoxynuleotide and the synergistic effect of chitosan-nanoparticles (CNP) with CpG on immune responses of mice, which were used to develop a novel immunoadjuvant to boost immune response to conventional vaccines.

METHODSA novel CpG ODN containing 11 CpG motifs was synthesized and its bioactivities to stimulate the proliferation of lymphocytes of pig in vitro were detected. Then it was entrapped with CNP prepared in our laboratory by the method of ionic cross linkage, and immunized Kunming mice were co-inoculated with paratyphoid vaccine. The peripheral blood was collected weekly from the tail vein of inoculated mice to detect the contents of IgG, IgA, IgM, and specific antibody against salmonella as well as the levels of interleukin-2 (IL2), IL-4, and IL-6 by SABC-ELISA assay. The numbers of leucocytes, monocytes, granuloytes, and lymphocytes were calculated separately using the routine method. The experimental mice were orally challenged with virulent salmonella 35 days after inoculation.

RESULTSThis CpG ODN could remarkably provoke the proliferation of lymphocytes of pig in vitro in contrast with the control (P < 0.05). Compared with those of the control, immunoglobulins, including IgG, IgA, IgM, and specific antibodies to paratyphoid vaccine, increased significantly in sera from the CpG or CpG-CNP-vaccinated mice (P < 0.05). IL-2, IL-4, and IL-6 increased remarkably in sera from immunized mice (P < 0.05). The leucocytes, monocytes, granuloytes, and lymphocytes of the mice immunized with CpG or CpG-CNP were also increased in number (P < 0.05). After the challenge, these immunity values were elevated in the mice vaccinated with CpG or CpG-CNP. The immunized mice all survived, while the control mice fell ill with evident lesions with diffuse hemorrhage in stomach, small intestine, and peritoneum.

CONCLUSIONSCpG ODN entrapped with CNP is a promising effective immunoadjuvant for vaccination, which promotes humoral and cellular immune responses, enhances immunity and resistance against salmonella by co-administration with paratyphoid vaccine.

Adjuvants, Immunologic ; administration & dosage ; pharmacology ; Animals ; Antibodies, Bacterial ; blood ; Cell Proliferation ; Chitosan ; chemistry ; Drug Therapy, Combination ; Enzyme-Linked Immunosorbent Assay ; Immunoglobulin Isotypes ; blood ; Interleukins ; blood ; Lymphocyte Activation ; drug effects ; Lymphocytes ; cytology ; Mice ; Nanoparticles ; chemistry ; Oligodeoxyribonucleotides ; administration & dosage ; pharmacology ; Paratyphoid Fever ; immunology ; prevention & control ; Salmonella ; physiology ; Salmonella Infections, Animal ; immunology ; prevention & control ; Swine ; immunology ; Typhoid-Paratyphoid Vaccines ; immunology

This experiment was conducted to assess the efficacy of typhoid vaccine newly produced by purifying Vi antigen of Salmonella typhi. With Karber method, LD50 of challenging organism (S. typhi ty2) was determined as 6.31 CFU/mouse, and then the organism was used for the study. With Probits method, ED50 of the vaccine was determined as 0.016 microgram / 0.5 ml / mouse. The ELISA titer (0.5097+/-0.0606) was 4 times in the group treated with high dose (0.25 microgram/0.5ml) as in control (0.1113+/-0.0110). Six major protein bands of 66, 55, 35, 33, 18, and 9 kd were detected in Western blot analysis with serum of a vaccine treated mouse, whereas only one weak band of about 35 kd was detected with serum of a control mouse. We concluded that typhoid vaccine produced by purifying Vi antigen of S. typhi very effectively prevent S. typhi infection in mice.
Animals ; Antibodies, Bacterial/immunology ; Antigens, Bacterial/*immunology/*isolation&purification ; Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; Lethal Dose 50 ; Logistic Models ; Male ; Mice ; Mice, Inbred BALB C ; Polysaccharides, Bacterial/*immunology/*isolation&purification ; Salmonella typhi/chemistry/*immunology ; Typhoid Fever/immunology/prevention&control ; Typhoid-Paratyphoid Vaccines/administration & dosage/*immunology/*isolation&purification