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Pathogen
(Target Population)
|
Type of Vaccine
|
Clinical Trial Difficulty
|
|
Rabies virus
(Individuals at high risk, plus post-exposure prophylaxis)
|
Vero cell
|
Little; depends on antibody response
|
|
(Same)
|
Glycoprotein produced by rDNA technology in mammalian cells
|
Fatal natural disease and current availability of effective vaccine require rigorous proof of likely efficacy prior to field trials
|
|
(Birth cohort in areas of high risk)
|
Attenuated live vector virus containing gene for protective glycoprotein antigen
|
Some possible apprehension over new approach
|
|
Respiratory syncytial virus
(Infants)
|
Polypeptides produced by recombinant DNA technology
|
Difficult. Needed very early in life; need rapid response. Vaccines won’t take in persons with antibodies
|
|
Attenuated live virus
|
|
|
Rotavirus
(Infants, 0–6 months)
|
Attenuated high passage bovine rotavirus
|
Relatively easy. Pathogen present everywhere in world. Can do trial in children<1 year
|
|
Attenuated low passage bovine rotavirus
|
|
Rhesus monkey rotavirus
|
|
Salmonella typhi
(Children; young adults at risk; travelers from developed countries to endemic areas)
|
Attenuated ga1E mutant S. typhi strain TY21a
|
Trials largely completed; further work needed to optimize vaccine
|
|
Aromatic amino acid dependent strains of S. typhi
|
|
Shigella spp.
(Infants at birth or earliest possible age; elderly for epidemic strains)
|
Probably plasmid mediated outer membrane protein invasion determinant (small number of promising options need investigation to determine best approach)
|
Moderate to difficult
|
|
Streptococcus A
(Children,<3 to 4 years)
|
Synthetic M protein segment
(excluding portions cross-reacting with human tissue)
|
Moderate to very difficult
|
|
Streptococcus pneumoniae
(Infants)
|
Conjugated polysaccharides, polyvalent
|
Requires high degree of patient and physician cooperation. Multitude of bacterial types creates problems of accurately determining vaccine efficacy
|
|
Vibrio cholera
(Children, especially <2 years)
|
Genetically defined live mutant V. cholerae (A−B+ or A−B−) with respect to toxin subunit synthesis
|
Difficult. Need large populations in hyperendemic areas. Screening possible in volunteers
|
|
Inactivated antigens
|
Difficult. Same problems as live
|
|
Yellow fever virus
(Young children)
|
Attenuated live virus produced in cell culture
|
Ethical problems in field testing an improved vaccine when an effective one already exists
|
