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PubMedDate not supplied

Who introduced typhoid vaccination: Almroth Write or Richard Pfeiffer?

The British pathologist Almroth Wright generally is credited with the initiation of typhoid vaccination in 1896. His claims of priority were challenged as early as 1907 in favor of Richard Pfeiffer, a German bacteriologist and a student of Robert Koch. A review of the original literature of the 1890s and the early 1900s revealed that several groups were working on typhoid vaccine at the same time and that the credit for the initiation of typhoid vaccine studies should be shared by these two great researchers.

England↗
PubMed1980

Practical evaluation of a pilot immunization campaign against typhoid fever in a Cambodian refugee camp.

An outbreak of typhoid fever in the largest refugee camp of the besieged capital of Phnom-Penh, Cambodia, and availability of a locally manufactured Anti-Tetanus-Typhoid-Paratyphoid vaccine prompted us to test the practicability of a mass immunization campaign by carrying out a trial in the smaller, well delineated refugee camp of Pochentong. Initial acceptance was good, due to a comprehensive service (information, health education and individual care of patients). Attendances by adults and children showed a steady decline with only 20% completing the course. It is concluded that multiinjection immunization campaigns against typhoid-paratyphoid are a waste of money in a war-torn situation with an unstable population.

Adolescent↗
PubMed1980

Decreased gut-associated IgA levels in patients with typhoid fever.

Gut and serum immune responses were studied in twenty-two patients with bacteriologically proved typhoid fever at different stages of the illness and six volunteers after parenteral immunizations with heat-killed typhoid vaccine. Whereas the former group had some specific antibodies in their intestinal aspirates and significant specific antibody responses in their sera, the latter could only mount a serum antibody response. Moreover, the intestinal IgA levels in the patients remained significantly decreased throughout the whole course of the illness, but a rise of IgG and IgM was observed in their jejunal secretions. In contrast, the levels of all the three major classes of serum immunoglobulins IgG, IgM and IgA were raised in the patients, as opposed to the volunteers, in whom only IgG and IgM levels were increased. It was inferred that the subjects with deficit of intestinal IgA, and thus lacking protective mucosal barrier, are more prone to develop typhoid fever.

Antibody Specificity↗
PubMed2004

Vaccination against typhoid fever in travellers: a cost-effectiveness approach.

Analysis of data on the incidence of typhoid fever and the costs of vaccination of travellers to the developing world indicates that vaccination may not be cost-effective for travel to countries with a moderate-to-high endemicity. It may be reasonable to selectively vaccinate travellers to countries with a very high incidence of typhoid fever, and particularly those who are visiting relatives or who will be in close contact with the local population. Vaccination of travellers on standard tourist itineraries is probably not necessary. The basic preventative measure for typhoid fever should be the avoidance of potentially contaminated food and drink.

Cost-Benefit Analysis↗
PubMed1984

Construction of a potential live oral bivalent vaccine for typhoid fever and cholera-Escherichia coli-related diarrheas.

We used the Salmonella typhi galactose epimerase (galE) mutant strain Ty21a, shown to be a safe, effective, living, attenuated oral typhoid vaccine, as a recipient for a recombinant plasmid containing the gene for production of the nontoxic B subunit of the heat-labile enterotoxin of Escherichia coli. The S. typhi derivative, strain SE12, produced heat-labile enterotoxin subunit B that was structurally and immunologically indistinguishable from heat-labile enterotoxin subunit B produced by strains of E. coli harboring the same plasmid. Tests in mice and guinea pigs showed that strain SE12 was safe when given orally and was capable of inducing a significant antitoxic antibody response when injected parenterally. Moreover, it retained the galactose sensitivity of the parent strain, preserving its utility as a typhoid vaccine. This strain may prove to be a useful live oral bivalent vaccine strain for typhoid fever and cholera-E. coli-related diarrheas.

Administration, Oral↗
PubMed1966

Characterization of "clearance" factor and "cell-bound" antibody in experimental typhoid.

Daizo, Ushiba (Keio University School of Medicine, Tokyo, Japan), Taiji Nakae, Takehisa Akiyama, and Yoshio Kishimoto. Characterization of "clearance" factor and "cell-bound" antibody in experimental typhoid. J. Bacteriol. 91:1705-1712. 1966.-The "clearance" factor produced in the serum of rabbits immunized with a killed vaccine of an S-type virulent strain of Salmonella enteritidis was identified as O agglutinin and characterized immunochemically as a class of macroglobulin with a sedimentation coefficient of 12.7S. The macroglobulin, which was isolated by means of diethylaminoethyl cellulose column chromatography and sucrose density gradient centrifugation, showed a single protein peak when subjected to cellulose acetate electrophoresis and analytical ultracentrifugation. Its activity as agglutinin and "clearance" factor was inactivated both by mercaptoethanol treatment and absorbtion with the specific O antigen. The H agglutinin was also isolated as a single globulin fraction with relatively low molecular weight, and was characterized as a 7S gamma-globulin. This fraction had no "clearance" activity. A macroglobulin, similar to that identified in the rabbit serum, was extracted with urea from the cells of mice immunized with the S-type killed vaccine, but not from mice immunized with a live vaccine (R-type mutant), although this latter vaccine is very effective in producing a solid immunity against typhoid disease. The relation of this "cell-bound" antibody to the mechanism of "cellular" immunity in experimental typhoid is discussed.

Animals↗
PubMed2005

A mass vaccination campaign targeting adults and children to prevent typhoid fever in Hechi; expanding the use of Vi polysaccharide vaccine in southeast China: a cluster-randomized trial.

BACKGROUND: One of the goals of this study was to learn the coverage, safety and logistics of a mass vaccination campaign against typhoid fever in children and adults using locally produced typhoid Vi polysaccharide (PS) and group A meningococcal PS vaccines in southern China. METHODS: The vaccination campaign targeted 118,588 persons in Hechi, Guangxi Province, aged between 5 to 60 years, in 2003. The study area was divided into 107 geographic clusters, which were randomly allocated to receive one of the single-dose parenteral vaccines. All aspects regarding vaccination logistics, feasibility and safety were documented and systematically recorded. Results of the logistics, feasibility and safety are reported. RESULTS: The campaign lasted 5 weeks and the overall vaccination coverage was 78%. On average, the 30 vaccine teams gave immunizations on 23 days. Vaccine rates were higher in those aged < or = 15 years (90%) than in adolescents and young adults (70%). Planned mop-up activities increased the coverage by 17%. The overall vaccine wastage was 11%. The cold chain was maintained and documented. 66 individuals reported of adverse events out of all vaccinees, where fever (21%), malaise (19%) and local redness (19%) were the major symptoms; no life-threatening event occurred. Three needle-sharp events were reported. CONCLUSION: The mass immunization proved feasible and safe, and vaccine coverage was high. Emphasis should be placed on: injection safety measures, community involvement and incorporation of mop-up strategies into any vaccination campaign. School-based and all-age Vi mass immunizations programs are potentially important public health strategies for prevention of typhoid fever in high-risk populations in southern China.

Adolescent↗
PubMedDate not supplied

An open randomized study of inactivated hepatitis A vaccine administered concomitantly with typhoid fever and yellow fever vaccines.

BACKGROUND: Concomitant administration of several vaccines is a common practice when travel clinics prepare persons for international travel. The purpose of the study was to compare the immunogenicity and safety of hepatitis A, typhoid fever, and yellow fever vaccines administered concomitantly with hepatitis A vaccine administered alone and typhoid fever and yellow fever vaccines administered alone. METHODS: Healthy adults 18 to 55 years of age were randomized to receive either VAQTA, TyphimVi, and YF-VAX on day 0 and VAQTA at week 24 (Group 1); TyphimVi and YF-VAX on day 0 and an optional dose of VAQTA 1 month later (Group 2); or VAQTA at day 0 and week 24 (Group 3). RESULTS: From March to December 1997, a total of 240 subjects were enrolled, 80 in each treatment group. Most were female and Caucasian, and the mean age was 29.4 years. Four weeks after vaccine dose 1, seroconversion to protective antibody levels against hepatitis A was 95.9% in Group 1 and 100% in Group 3. In Group 1, 93.4% of subjects demonstrated at least a 4-fold rise in neutralizing antibody levels against typhoid, compared with 90% in Group 2. Serum neutralizing antibody against yellow fever developed in 98.6% of subjects in Group 1 compared with 100% in Group 2. CONCLUSIONS: These findings were consistent with similarity in the immune responses between treatment groups as defined a priori. The adverse experience (AE) profile did not appear to be substantially affected by concomitant administration of all three vaccines. Providing these three vaccines concomitantly can simplify the process of obtaining pretravel prophylaxis and may help ensure that all needed vaccines are administered.

Adolescent↗
PubMedDate not supplied

Combined vaccination against hepatitis A, hepatitis B, and typhoid fever: safety, reactogenicity, and immunogenicity.

BACKGROUND: The etiological agents of hepatitis A, hepatitis B, and typhoid fever share similar patterns of global distribution, and cause significant disease burden in travelers to endemic countries. Combined vaccination against all three diseases, based on currently available vaccines, would promote compliance and convenience for travelers. This clinical study evaluated the feasibility of extemporaneously syringe-mixed hepatitis A and B vaccine (Twinrix) and a Vi polysaccharide vaccine (Typherix) in healthy adults, and compared this to concomitant administration of the vaccines in separate arms. METHODS: The mixed dose of vaccine contained at least 720 enzyme-linked immunosorbent assay (ELISA) units of the inactivated hepatitis A antigen, 20 microg of the recombinant hepatitis B antigen and 25 microg of the Vi polysaccharide typhoid antigen in 1.5 mL. The study was conducted in 200 healthy 18- to 45-year-old volunteers. RESULTS: Equivalence between the vaccines mixed before administration and the concomitantly administered vaccines was shown in terms of seroconversion and seroprotection. With the exception of local injection site soreness, which was higher in the mixed administration group, the reactogencity was similar for both groups. In both vaccination groups more than 95% of the subjects were anti-hepatitis A virus and anti-Vi seropositive 1 month after the first vaccination. With regard to hepatitis B, a strong response was achieved in both groups, with more than two-thirds of the subjects protected 2 months after the start of the immunization course. CONCLUSION: These results support the feasibility of extemporaneously syringe-mixed combined hepatitis A and B vaccine with a Vi polysaccharide typhoid vaccine, administered in healthy adults.

Adult↗
PubMed2002

Characterization of CD8(+) effector T cell responses in volunteers immunized with Salmonella enterica serovar Typhi strain Ty21a typhoid vaccine.

Salmonella enterica serovar Typhi (S. typhi) strain Ty21a remains the only licensed attenuated typhoid vaccine. Despite years of research, the identity of the protective immunological mechanisms elicited by immunization with the Ty21a typhoid vaccine remains elusive. The present study was designed to characterize effector T cell responses in volunteers immunized with S. typhi strain Ty21a typhoid vaccine. We determined whether immunization with Ty21a induced specific CTL able to lyse S. typhi-infected cells and secrete IFN-gamma, a key effector molecule against intracellular pathogens. We measured the functional activity of these CTL by a (51)Cr-release assay using 8-day restimulated PBMC from Ty21a vaccinees as effector cells and S. Typhi-infected autologous PHA-activated PBMC as target cells. Most vaccinees exhibited consistently increased CD8-mediated lysis of targets by postimmunization PBMC when compared with preimmunization levels. We also developed an IFN-gamma ELISPOT assay to quantify the frequency of IFN-gamma spot-forming cells (SFC) in PBMC from Ty21a vaccinees using an ex vivo system. Significant increases in the frequency of IFN-gamma SFC following immunization (mean +/- SD, 393 +/- 172; range 185-548 SFC/10(6) PBMC; p = 0.010), as compared with preimmunization levels, were observed. IFN-gamma was secreted predominantly by CD8(+) T cells. A strong correlation was recorded between the cytolytic activity of CTL lines and the frequency of IFN-gamma SFC (r(2) = 0.910, p < 0.001). In conclusion, this work constitutes the first evidence that immunization of volunteers with Ty21a elicits specific CD8(+) CTL and provides an estimate of the frequency of CD8(+) IFN-gamma-secreting cells induced by vaccination.

Adult↗
PubMed1993

Use of oral typhoid vaccine strain Ty21a in a New York state travel immunization facility.

One hundred fifty-seven travelers who received the new oral typhoid vaccine strain Ty21a between April 1990 and February 1992 were surveyed by questionnaire to assess compliance and toxicity. The four-dose vaccine should be taken every other day before meals, and kept refrigerated between doses. Noncompliance with one or more of these instructions was seen in approximately 30% of travelers. Thirty-four (21.6%) took one or more doses after meals, 13 (8.3%) did not take all four doses, 10 (6.4%) failed to take the dose every other day, and five (3.2%) did not keep the vaccine refrigerated. The vaccine was well-tolerated and only 14 (8.9%) had one or more minor side effects. Of 59 (38%) who had received injectable typhoid vaccine previously, all preferred oral versus injectable vaccine, and reported moderate-to-severe side effects with the injectable form. Until a single-dose, oral typhoid vaccine is available, Ty21a is an attractive option. To achieve maximum efficacy, the importance of compliance should be emphasized.

Administration, Oral↗
PubMed1975

Controlled field trial of a typhoid vaccine prepared with a nonmotile mutant of Salmonella typhi Ty2.

A controlled field trial was performed in Egypt to evaluate a whole cell typhoid vaccine prepared with a nonmotile mutant of S. typhi Ty2 (TNM1) devoid of flagellar antigen. This vaccine did not elicit an H antibody response, but significant Vi and O agglutinin responses were observed. There were 34 typhoid cases among 21 063 six- to seven-year-old children who received the TNM1 vaccine, and 44 cases among 21 017 children in the control group who received tetanus toxoid. These results suggest that TNM1 vaccine does not provide protection against typhoid fever, and that H antigen may be an important component of an effective vaccine.

Child↗
PubMed2001

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China.

OBJECTIVE: To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. METHODS: A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). FINDINGS: After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. CONCLUSION: The slightly higher dose of vaccine did not seem to alter efficacy significantly in China.

Adolescent↗
PubMed1992

[Typhoid fever in school children: by what measures is the modification of the clinical course due to oral vaccination?].

The clinical course of infection by Salmonellae was compared between patients who had been vaccinated against typhoid fever using the Ty21a vaccine and those who had not. Of 2566 bacteriological confirmed cases 84% were infected with S typhi, 14% with S paratyphi B and 2% with S paratyphi A. Among patients with typhoid fever, 34% were treated in hospital, 3.5% had relapses, 5.4% developed complications and 1 patient died (0.05%). Among patients with paratyphoid fever, 18% were treated in hospital, 0.6% had relapses, 1.4% developed complications and there were no deaths. These figures were similar among vaccinated and non-vaccinated cases. A slightly greater proportion of vaccinated cases were treated in hospital (38 vs 30%). Thus, use of oral vaccination against typhoid fever does not alter the clinical course of infection with Salmonellae.

Administration, Oral↗
PubMed1965

EVALUATION OF TYPHOID VACCINES IN THE LABORATORY AND IN A CONTROLLED FIELD TRIAL IN POLAND. PRELIMINARY REPORT.

In 1961 a controlled field trial of anti-typhoid vaccines was carried out in 25 regions in Poland. Four types of vaccine were studied: (1) bacterial acetone-killed and -dried vaccine (two kinds), (2) bacterial formol-killed phenol-preserved vaccine, (3) Westphal's endotoxin adsorbed on aluminium hydroxide, and (4) Grasset's vaccine (autolysate of typhoid bacilli adsorbed on aluminium hydroxide). The control vaccine was tetanus toxoid. A total of 690 655 persons received two inoculations. Prior to the field trial, laboratory tests were carried out on the vaccines, postvaccinal reactions were studied, and a serological examination was made of randomly selected blood samples. The vaccination was followed by a two-year survey of cases of typhoid and other diseases. Among children aged 5-14 years, the formol-killed phenol-preserved vaccine was found to be the most effective and Grasset's vaccine the least. Among adults aged 15-60 years, no conclusive evidence for the effectiveness of the vaccines could be obtained owing to the small number of cases. This may be due to the maintenance of immunity through repeated annual vaccination with bacterial vaccines.

Adolescent↗
PubMed1952

Changing epidemiologic aspects of typhoid fever in California.

Typhoid fever in California is no longer a major public health problem. The previously high incidence of water- and milk-borne infections has been greatly reduced. Human carriers now are the source of most infections. Chloramphenicol has proven to be a valuable aid in the therapy of the acutely ill patient, but it has not as yet solved the therapeutic or public health problems of typhoid fever. It continues to be vital for the protection of the public that every suspected case of typhoid fever be definitely established by appropriate public health laboratory procedures, that thorough investigation be carried out to determine the source of infection, and that careful follow-up examinations be done so that if a carrier state develops, proper measures can be taken.

Biometry↗
PubMed1990

The effect of oral and parenteral typhoid vaccination on the rate of infection with Salmonella typhi and Salmonella paratyphi A among foreigners in Nepal.

We studied the incidence of enteric fever among travelers and foreign residents who attended an expatriate clinic in Kathmandu, Nepal, from February 1987 to June 1988. There were 42 cases of enteric fever; 20 were caused by Salmonella typhi and 22 by Salmonella paratyphi A. Among 18 unvaccinated foreigners who had enteric fever, S typhi was isolated from 67%, and S paratyphi A from 33%, a ratio similar to the local Nepalese population. Among 22 vaccinated foreigners, S typhi was isolated from 35%, compared with 65% with S paratyphi A. Nine percent of tourists had received the oral Ty21A typhoid vaccine. However, among seven vaccinated tourists who became infected with S typhi, four (57%) had received the oral vaccine. Typhoid vaccine efficacy for tourists was calculated and showed an overall protective rate of 90% against enteric fever in general, 95% protection against S typhi, and 72% to 75% protection against S paratyphi A. We conclude that typhoid vaccine should be recommended to all travelers to the Indian subcontinent, and since S paratyphi A is the predominant cause of enteric fever among vaccinated travelers, consideration should be given to an effective vaccine against S paratyphi A when that becomes available.

Administration, Oral↗
PubMed1971

Effectiveness of oral killed typhoid vaccine.

A controlled field trial of oral killed typhoid vaccine was carried out in Delhi, India in 1968-69. Altogether, 13 374 children below the age of 17 years were included in the study. Two comparable groups of children were given either placebo or vaccine. Each tablet of vaccine contained 100x10(9) killed Salmonella typhi, and 3 tablets of vaccine or placebo were administered to each child. The vaccinated subjects were followed up from 10 June 1968 to 31 August 1969. The effectiveness of the vaccine was measured by comparing the incidence of typhoid fever (based only on bacteriologically positive cases) in the two groups. It was found that the difference in incidence of the disease in the two groups was not statistically significant. The oral killed typhoid vaccine in the dosage schedule used in the present trial was found not to be effective against the disease.

Administration, Oral↗