Vaccines under development

Anonymous "Biotechnology Therapeutic Medicines and Vaccines Under Development , Genetic Eng. News. 16(16), 29 -34 (1996). 

Table 8.3 Some AIDS Vaccines Under Development...

The application of the DNA vaccine technology is not limited to infectious diseases and is currently being used in therapeutic vaccines against cancer. Table 18.4 presents the therapeutic DNA vaccines under development (Powell, 2004). 

Advisory Committee on Immunizations Practices (ACIP) makes recommendations on guidelines for the administration of vaccines. The Government Reform Committee staff report found that the majority of members of both committees have financial ties to vaccine manufacturers or hold patents on vaccines under development. 

The implications of those safety requirements for urgently needed new adjuvants are significant. The adjuvant issue appears to be caught in a vicious circle. Risky vaccine projects cannot afford the extra risk and cost of an adjuvant development project, which could cost several million dollars. On the other hand, the success of several recombinant vaccines under development seems to depend on new and better adjuvants. The lack of clearly superior adjuvant candidates with reproducible effects aggravates this current situation. 

Candidate vaccines under development are immunogenic and confer protection against lethal aerosol exposures. Recent animal studies have shown that either active immunization or passive prophylaxis may be effective against intravenous or intraperitoneal intoxication with ricin (Poh et al, 1994). In the case of inhalational exposure, active immunization or prophylactic administration of aerosolized specific anti-ricin antibody may also be effective (Poli et al, 1994). Unfortunately, these applications may not be clinically available since they are still under investigation. 

C. Prophylaxis. There is currently no prophylaxis approved for human use. Ricin is not dermally active therefore, respiratory protection is the most critical means of prevention (similar to chemical agent exposure). Vaccines under development are immunogenic and confer protection against lethal aerosol exposures in animals. 

New approach of vaccines DNA vaccines and plant-derived vaccines, under development but still not licensed. 

Vaccines There is currently no human vaccine available to prevent SEB intoxication. One has been under development since 1996. Be certain to wear a protective mask when dealing with patients. 

Treatment — A number of antibiotics are available including doxycycline combined with rifampin, and ofloxacin combined with rifampin. Vaccines for animal use directed against B. melitensis and B. abortus have proven very successful. An effective vaccine for human use against B. suis is currently under development.3... 

Treatment — No vaccine or antitoxin is available both are under development. Supportive management depends on the route of exposure and therefore is varied.3... 

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... 

Vaccine and antitoxin are under development Supportive management varies depending on the route of exposure... 

Ideally, the most effective prevention of HIV infection would be a vaccine that blocks virus infection in individuals. Indeed, effective vaccines have been developed against most human viruses that cause serious diseases. While several different possible vaccines against HIV are under development, there are some theoretical reasons why it may be difficult to develop an effective one. First, HIV has the unique ability to evade the immune system in an infected individual. Briefly, this results from (1) the high mutation rate of the virus, particularly in the env gene (2) the ability of the virus to establish a latent state in some cells and (3) the ability of the virus to spread by cell-to-cell contact. The object of the vaccine is to raise a protective immune response to the infectious agent. Since HIV evades the immune system so efficiently, it may be difficult for a vaccine to prevent HIV infection in an individual, even if it can induce production of neutralizing antibodies or cell-mediated immunity. 

Despite these theoretical concerns, a number of HIV vaccines are under development. Most of these vaccines have been developed by recombinant DNA techniques that have allowed a large-scale production of individual viral proteins. The predominant HIV proteins that make up these potential vaccines are env proteins (e.g., gp 120) and, to a lesser extent, gag proteins. In addition, inactivated whole HIV virus is being tested. 

Another anti-cocaine drug is under development by DrugAbuse Sciences, Inc., a California company whose business plan is built solely upon developing pharmacotherapy drugs. DrugAbuse Sciences is racing to develop DAS-431, a cocaine vaccine that the company aims to release in both an injectable form as well as an inhalable aerosol. ... 

For example, one of the technical characteristics that might be specihed is the effectiveness of the vaccine in giving protection over a period of, say, two years. Suppose a vaccine is developed such that only 50% of the people vaccinated appear to obtain protection. This can raise two problems. If the partially effective vaccine is determined inadmissible to be paid under the Advanced Purchase Commitment plan, despite bringing immense health benehts to millions of people, the innovator is not adequately compensated. But, if it is deemed admissible (perhaps only for a scaled reward), the Advanced Purchase Commitment funding could be used up in a short time, so that a second, 100% effective vaccine expected to arrive two years later might obtain no Advanced Purchase Commitment subsidy at all. 

Maintenance of conditions in the culture environment that keep stress to a minimum is one of the best methods of avoiding diseases. Vaccines have been developed against several diseases and more are under development. Selective breeding of animals with disease resistance has met with only limited success. Good sanitation and disinfection of contaminated facilities are important avoidance and control measure. Some disinfectants are listed in Table 6. Pond soils can be sterilized with burnt lime (CaO), hydrated lime [Ca(OH)2], or chlorine compounds (12). 

No approved vaccine exists for any of the VHP infections other than yellow fever. A Lassa virus vaccine currently under development at USAMRIID has shown good efficacy in nonhuman primates (Geisbert, 2005). Collaborative efforts between the Canadian Special Pathogens Program and researchers from USAMRIID have led to the development of an experimental filovirus vaccine that also provides protection to nonhuman primates in a laboratory setting (Feldmann, Jones, Schnittler, Geisbert, 2005). 

Not currently available, except for Lassa fever. Other vaccines are under development. 

Naturally acquired immunity offers the most reliable protection for people living permanently in endemic areas (below). Repeated attacks of malaria confer partial immunity and the disease often becomes no more than an occasional inconvenience. Vaccines to confer active immunity are under development. 

---