Typhoid fever vaccine

A combined meningococcal and typhoid vaccine (Merieux) was evaluated in 158 volunteers in a singleblind study (11). Comparing the effects with those in vaccinees receiving monocomponent vaccines or the combination vaccine, there was no significant difference in the reported frequency or duration of local and systemic reactions. However, vaccinees who received the monocomponent typhoid fever vaccine alone were less likely to complain of swelling or pain at the injection site. 

A meta-analysis of studies of the efficacy and toxicity of typhoid fever vaccines (SEDA-23, 343) has been criticized as an interesting mathematical exercise but of httle practical relevance (4). The meta-analysis had lumped together different parenteral whole-ceU vaccines (alcohol-inactivated, formahn-inactivated, acetone-inactivated, and dried whole-ceU vaccines), but the only... 

Table 1 Local and systemic reactions after the administration of typhoid fever vaccines...

Engels EA, Falagas ME, Lau J, Bennish ML. Typhoid fever vaccines a meta-analysis of studies on efficacy and toxicity. BMJ 1998 316(7125) 110-16. 

Clemens J, Hoffman S, Ivanoff B, Kingman K, Levine MM, Neira M, Pang T. Typhoid fever vaccines. Vaccine 1999 17(20-21) 2476-8. 

Engels EA, Ealagas ME, Lau 1, Bennish ML (1998) Typhoid fever vaccines - a metaanalysis of studies on efficacy and toxicity. Br Med 1 316 110-116... 

The award of a Beit Memorial Fellowship for medical research in 1933 provided him with more financial security and independence. Stacey moved to London and for the next 3 years worked full-time in Raistrick s laboratory. He was given the task of working on vaccines against typhoid fever. The work was successful eventually and the vaccines were used by the Royal Air Force and also were sent to the Air Force in New Zealand. Also, some advances were made in studies of the carbohydrate components of the vaccines. In addition to this research, he completed, by part-time study, the diploma course in bacteriology. 

The ideal of any vaccine is to provide life-long protection to the individual against disease. Immunological memory (Chapter 14) depends upon the survival of cloned populations of small B and T lymphocytes (memory cells). These small lymphocytes have a lifespan in the body of ca. 15-20 years. Thus, if the immune system is not boosted, either by natural exposure to the organism or by re-immunization, then immunity gained in childhood will be attenuated or lost completely by the age of 30. Those vaccines which provide only poor protection against disease have proportionately reduced time-spans of effectiveness. Yellow fever vaccination, which is highly effective, must therefore be repeated at 10-year intervals, whilst typhoid vaccines are only effective for 1-3 years. Whether or not immunization in childhood is boosted at adolescence or in adult life depends on the relative risks associated with the infection as a function of age. 

Typhoid vaccines Killed Salmonella typhi Active immunization against typhoid fever... 

Typhoid vaccines are used for active immunisation against typhoid fever. Two types of vaccine, one injectable and other oral are available. 

Currently there are no commercially available vaccines for salmonellosis, but vaccines for typhoid fever are given to travelers going to countries with endemic disease. For most strains of Salmonella spp., antibiotics (specifically ampicillin, gentamicin, ciprofloxacin, and a combination of trimethoprim and sulfamethoxazole) are effective for both typhoid fever or severe salmonellosis some serotypes... 

Vaccines also may be used to boost specific immune processes directed against the bacteria themselves or against adherence appendages, cytotoxins, or enterotoxins. Currently available vaccines for typhoid fever in the United States are the parenteral Vi capsular polysaccharide vaccine, the oral live-attenuated Ty21a vaccine, and the older heat-phenol-inactivated parenteral vaccine. Only the older parenteral cholera vaccine is licensed for use in the United States, but it is not recommended owing to the low risk of cholera to the traveler and the limited efficacy of the vaccine. New oral five and killed vaccines are licensed outside the United States and are used by some travelers. The rotavirus vaccine, although effective, has presented complications in the form of rare cases of intussusceptions it is no longer marketed and thus is not recommended. ... 

In developed countries the main source of typhoid fever is from travelers returning home having visited endemic areas and being exposed to infection. For travelers to endemic areas vaccines type Ty21a and Vi are recommended. The same applies to laboratory workers handling Salmonella enteric serotype and household members of typhoid carriers. 

Tarr PE, Kuppens L, Jones TC, Ivanoff B, Aparin PG, Heymann DL (1999) Considerations regarding mass vaccination against typhoid fever as an adjunct to sanitation and public health measures potential use in an epidemic in Tajikistan. Am 1 Trop Med Hyg 61 163-170... 

This bacterial vaccine is used for primary immunization (exposure to typhoid carrier or plans to travel to an area endemic for typhoid fever). 

Remember that you will need to complete your vaccination at least 1 week before you travel so that the vaccine has time to take effect. Typhoid vaccines lose effectiveness after several years if you were vaccinated in the past, check with your doctor to see if it is time for a booster vaccination. Taking antibiotics will not prevent typhoid fever they only help treat it. 

The other major health care products produced with the help of industrial fermentation are bacterial vaccines, therapeutic proteins, steroids, and gene therapy vectors. There are two categories of bacterial vaccines living and inactivated vaccines. Living vaccines consist of weakened, also known as attenuated, bacteria. Examples of living vaccines include those for diseases such as anthrax, which is caused by Bacillus anthracis, and typhoid fever, which is caused by Salmonella typhi. Inactivated vaccines are composed... 

---