CHALLENGES IN DEVELOPING AND TESTING HIV/AIDS VACCINES IN AFRICA

INTRODUCTION

Five million family became infected with HIV worldwide and three million died in 2003 alone-the highest ever1 sum of two units thirds of all people with HIV/AIDS are in Africa. Sub-Saharan Africa is the region of the world that is greatest in quantity affected by HIV/AIDS. An estimated 266 million clan are living with HIV/AIDS, and approximately 32 million of recent origin infections occurred in sub-Saharan Africa in 2003 In just the past year, the epidemic has claimed the lives of an estimated 23 million Africans. Ten million young clan and almost three million children below 15 are living with HIV/AIDS. An estimated eleven million children have been orphaned by means of AIDS in subSaharan Africa.2

Although there have been more than 45 million cumulative HIV infections in Africa, there have been sole two small phase 1 preventive HIV vaccine trials in the continent greatest in quantity severely affected by the pandemic.3 The first HIV vaccine trial in Africa of a production based on HIV strains from that continent began in Nairobi, Kenya in 2001 A collaborative assemblage including Oxford University, UK, the University of Nairobi, Kenya, the Kenyan AIDS Vaccine Initiative (KAVI), and the International AIDS Vaccine Initiative (IAVI) exhibited DNA Vaccine and modified Vacina Ankara Vaccines upon the basis of the gag gene of HIV-I subtype A and multiple cytotoxic Tlymphocyte epitopes, including a certain number of identified in studies of expos uninfected Kenyan female sex workers.4 The next to the first vaccine initiative was in southern Africa, using Clade C, the greatest in quantity common subtype in the world.

Currently nine approved vaccines are being proofed world-wide, including six in Africa: single in Botswana, two in Kenya, sum of two units in South Africa and individual in Uganda.5

Most HIV vaccine unravelling and assessment has taken place in disentangleed western countries. Early efforts to disentangle an HIV vaccine were based upon the HIV-I subtype B strains prevalent in western nations, and greatest in quantity human clinical trials were done in the United States and Europe Globally, there have been more than 80 Phase I and Phase II trials and single one product-a bivalent recombinant gp120 vaccine (AIDSVAX, VAXGEN Brisbane, CA, USA)-has reached large scale Phase III efficacy testing in North America, the Netherlands and Thailand.6

Studies of multiply expos on the contrary uninfected individuals and long-term nonprogressors provide evidence that cellular replys can provide some protection against HIV/AIDS. Almost all humans unravel some form of immune reply to HIV infection. Particularly encouraging have been studies of several vaccine conceptions tested against simian immunodeficiency virus (SIV), a virus similar to HIV that infects certain species of monkeys7

A vaccine for Africa would be the best long-term preventive measure against the HIV/AIDS pandemic in the continent. Historically, vaccines have provided a safe, require to be paid [i]or[/i] undergone effective, and efficient means of preventing illness, disability and death from infectious diseases. Because there are many HIV-I subtype circulating recombinant forms, and intersubtype recombinant strains in the continent, and since the distribution of these subtype will probably change overtime,8 an ideal HIV vaccine for Africa will be single that can protect against all genetically HIV-I strains (polyvalent HIV-I vaccine).

A vaccine is a remedy that mimics a dangerous organism or pathogen, and creates immune a whole memory concerning that specific pathogen.9 A vaccine is antigenically similar to a pathogen or to its toxic by-product on the contrary has been treated so that it can be administered to race with little danger of disease. The vaccine sensitizes the immune a whole to the corresponding pathogen, inducing immunity without the danger of infectious disease developing during the lag period. In immunized tribe natural exposure to the corresponding virulent pathogen triggers a protective anamnestic reply that eradicates the pathogen or neutralizes toxins before symptoms of disease lay open An effective vaccine retains the corresponding pathogen's antigens on the other hand none of the pathogen's ability to damage the entertainer This is accomplished in a number of ways including the use of killed and attenuated organisms, purified antigen-fractions, toxoid, synthetic peptides and anti-idiotype antibodies.10

Vaccines are disease specific: A vaccine against polio countenances only against polio and a vaccine against HIV infection shields only against HIV. In the case of a vaccine against viruses, this can either be an "inactivated" virus or an attenuated or mild form of a "live" virus.11

Inactivated vaccines are viruses that have missing their infectivity through damage to their nucleic acid by means of various agents such as formaldehyde or U V irradiation. These inactivating agents and treatments must be carefully single outed and controlled so that they will not affect the antigenic specificity of the protein surface of the respective virus.

Live vaccines are virus strains that from one side passage of a typical entertainer animal or cultured cells, have been made to mutate and have become "mild" or of depressed virulence, for the species to be vaccinated.