Yellow fever vaccines

Embryonated hens eggs are still the most convenient hosts for the growth of the vimses that are needed for influenza and yellow fever vaccines. Influenza vimses accumulate in high litre in the allantoic fluid of the eggs and yellow fever vims accumulates in the nervous systems of the embryos. 

For those infectious diseases that are transmitted to humans via insect vectors the onset and decline phases of epidemics are rarely observed other than as a reflections of the seasonal variation in the prevalence of the insect. Rather, the disease is endemic within the population group and has a steady incidence of new cases. Diseases such as these are generally controlled by public health measures and environmental control of the vector with vaccination and immunization being deployed to protect individuals (e.g. yellow fever vaccination). 

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. 

IGIM should be injected into a deltoid or gluteal muscle. It does not affect the immune response of inactivated vaccines, oral polio virus, or yellow fever vaccine. The administration of live vaccines [e.g., measles, mumps, rubella (MMR) vaccine] concomitantly with IGIM may decrease the immune response significantly thus, MMR and varicella vaccine should be delayed for at least 3 and 5 months, respectively, after IGIM has been administered. Additionally, IGIM should not be given within 2 weeks of the MMR administration or within 3 weeks of the varicella vaccine to maximize the efficacy of the immunization.1... 

CDC Case Definition A mosquito-borne viral illness characterized by acute onset and constitutional symptoms followed by a brief remission and a recurrence of fever, hepatitis, albuminuria, and symptoms and, in some instances, renal failure, shock, and generalized hemorrhages. Laboratory criteria for diagnosis is (1) fourfold or greater rise in yellow fever antibody titer in a patient who has no history of recent yellow fever vaccination and cross-reactions to other flaviviruses have been excluded or (2) demonstration of yellow fever virus, antigen, or genome in tissue, blood, or other body fluid. 

Yellow fever vaccines Live attenuated strain of yellow fever virus... 

Vaccines The only licensed vaccine for VHF is yellow fever vaccine. 

For prevention of some types of viral hemorrhagic fevers, there is pre-exposure prophylaxis in the form of yellow fever vaccinations, and some vaccines are available as IND... 

Viral vaccines are cultivated on inanimate media. Some examples include hepatitis b vaccine, influenza virus vaccine, measles virus vaccine, rabies vaccine, rubella vaccine, and yellow fever vaccine. The viral vaccines are available as lyophilized powder for reconstitution, or suspension for injections,... 

Treatments with immune globulin vaccines are useful against Crimean Congo hemorrhagic fever, Rift Valley fever, Bolivian hemorrhagic fever, and Lassa fever Yellow fever vaccine is the only established and licensed vaccine for a hemorrhagic fever several others are under development... 

The antibody response to yellow fever vaccine was impaired in protein-deficient children with kwashiorkor compared to the well-nourished controls. Polio antibody production was normal in the malnourished children, all of whom also responded in the normal fashion to smallpox vaccination. They had no evidence of disseminated vaccinia (B8). In Guatemala, on the other hand, smallpox vaccination of children who had fully recovered from severe protein-calorie malnutrition led to a drop in their nitrogen retention with the added complication of disseminated vaccinia (V3). 

Smith CE, Turner LH, Armitage P. Yellow fever vaccination in Malaya by snbcntaneous injection and mnlti-ple pnncture. Nentrahzing antibody responses in persons with and withont pre-existing antibody to related virnses. Bnll World Health Organ 1962 27 717-27. 

Extraneous contamination can be a problem and the use of human serum is discouraged since early batches of yellow fever vaccine became contaminated with hepatitis B virus. For similar reasons normal human diploid fibroblast strains are the preferred cells as they can be shown to be free, not only of contaminating virulent viruses but also of transforming viruses (Furesz et al 1988). Such cells have replaced primary cells but they must be regularly tested for... 

Although the concept of patient variability had been articulated by the middle of the twentieth century, the concept that a difference between two groups could be due to chance was slow to be accepted. The first clinical trial to use a formal statistical analysis reportedly occurred in 1962. The study involved a comparison of antibody production after yellow fever vaccination by two different methods. Several years later (1966) a critique of statistical methods used in medical journal manuscripts suggested a lack of proper study design and data analysis. In this critique, the authors canonized the criterion of P < 0.05 for a difference between two groups to be considered not due to chance. 

Jackson, J. Dworkin, R. Tsai, T. McMullen, R. Kuchmak, N. Comparison of antibody response and patient tolerance of yellow fever vaccine administered by the Biojector needle-free injection system versus conventional needle/syringe injection. International Society of Travel Medicine Conference, Paris, 1993. 

A 21-year-old woman developed acute irreversible loss of vision to 0.05 and a nasal visual field defect in the left eye 2 weeks after immunization with hepatitis A and B and yellow fever vaccine. An MRI scan showed hyper-intense thickening of the optic nerve, and a diagnosis of optic neuritis was made. Vision acuity did not recover but the scotoma disappeared within 6 weeks. 

Yellow fever vaccine contains the 17D virus strain grown in chick embryo tissue. The older (Dakar) yellow fever vaccine was prepared from more virulent material and often caused encephalitis, the risk in children being particularly high (SED-8, 712). 

The adverse effects of yellow fever vaccine have been documented by an expert group of the WHO (1). 

Encephahtis occurred after yellow fever immunization in a child older than 3 years of age and one over 9 months a 13-year-old boy developed the disease 1 week after receipt of vaccine (2). The patient recovered after 1 month. There have been reports of encephalitis in a 29-year-old man and meningoencephahtis in two adults, suspected to be caused by the 17D yellow fever vaccine (3,4). 

Schoub BD, Dommann CJ, Johnson S, Downie C, Patel PL. Encephalitis in a 13-year-old boy following 17D yellow fever vaccine. J Infect 1990 21(l) 105-6. 

Fitzner J, Coulibaly D, Kouadio DE, Yavo JC, Loukou YG, Koudou PO, Coulombier D. Safety of the yellow fever vaccine during the September 2001 mass vaccination campaign in Abidjan, Ivory Coast. Vaccine 2004 23(2) 156-62. 

Centers for Disease Control and Prevention (CDC). Fever, jaundice, and multiple organ system failure associated with 17D-derived yellow fever vaccination, 1996-2001. MMWR Morb Mortal Wkly Rep 2001 50(30) 643-5. 

Anonymous. Adverse events following yellow fever vaccination. Wkly Epidemiol Rec 2001 76(29) 217-18. 

Brazilian Yellow Fever Vaccine Evaluation Group. Serious adverse events associated with yellow fever 17DD vaccine in Brazil a report of two cases. Lancet 2001 358(9276) 91-7. 

Rawlinson WD. Hepatitis and death following vaccination with 17D-204 yellow fever vaccine. Lancet... 

Tseng J, Shieh W, Zaki SR, Al-Sanouri 1, Cutrona AF, Ray G, Weld LH, Cetron MS. Fever and multisystem organ failure associated with 17D-204 yellow fever vaccination a report of four cases. Lancet... 

Perhaps surprisingly, all of the most successful attenuated viral vaccine strains in current use were produced by empirical methods long before the genetic basis of pathogenesis by the specific pathogen was understood. Thus, attenuated strains of polio virus for use as a live, oral vaccine (Sabin) were selected by growth of viruses isolated from human cases under cultural conditions that did not permit replication of neuropathogenic virus. Comparable procedures were used to select the attenuated virus strains that are currently used in live measles, mumps, rubella and yellow fever vaccines. 

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