Lecture 32 Stopping HIV and AIDS Haiti Political instability deteriorating health services stigma resulting from religious 2 2 of Hait s population infected with HIV and conservative cultural views contribute to continued epidemic On March 4 1983 the U S Centers for Disease Control listed Haitians as one of the four high risk groups for AIDS Haitians singled out early on as only ethnic group inherently susceptible to new disease In US Haitians were fired denied employment housing and admission to schools 1990 1993 Haitian immigrants quarantined at Guantanimo Bay Preventable measures such as abstinence being faithful and condom use ABC have reduced the spread of HIV infection but have not stopped it There are no drugs that can cure HIV AIDS and drugs to treat the disease are expensive not wildely available in developing countries require faithful adherence to protocol and cause side effects The effects of the AIDS epidemic globally is devastating How Some Vaccines Work Modified live vaccines contain an attenuated or weakened version of a disease agent These vaccines create a mild form of the disease that stimulates a natural immune response Modified live vaccines are effective but can negatively impact the heath of the host Ex MMR OPV chicken pox Killed vaccines contain an inactivated disease causing agent These vaccines are designed to create antibodies without the negative effects of infection so are generally considered to be safe However during the inactivation process some of the surface antigens needed to create the desired antibodies may be destroyed thus reducing their effectiveness Examples Inactivated Influenza IPV Subunit vaccines use only the necessary parts of the virus to stimulate immunity Unlike modified live vaccines subunit vaccines stimulate the immune system to prevent disease without stressing out the animal And unlike killed vaccines subunit vaccines do a better job of disease prevention as they only contain concentrated amounts of the target antigen These qualities make subunit vaccines both safe and effective Hib HepA HepB Vaccine Development is a Long Road Ex Polio disease discovered in 1908 vaccine developed in 1955 Ex Measles Disease discovered in 1953 vaccine developed in 1995 How Preventative Vaccines Work During vaccination a vaccine with dead or harmless forms of viruses bacteria or other organisms is injected into your system The vaccine stimulates your immune system to produce antibodies against the organisms Any time you re exposed to this germ after vaccination the antibodies in your immune system attack and stop the infection Preventive Vaccine Strategies Preventive Vaccine Prevent infection in people who are HIV negative Accounted for the bulk of early vaccine research Human trials of over 100 HIV vaccines since 1984 Research has focused on encouraging the immune system to produce antibodies that would block the virus from infecting cells While successful in lab experiments preventive vaccines failed when mutated strains of HIV were introduced to the culture Medical News Experiment Shows AIDS Vaccine unlikely to Give Total Protection from Disease They tested vaccines on monkeys and they showed resistance however eventually some of the monkeys became sickened and passed away Medical News Hope for AIDS Vaccine Fades News of Superinfectious Case HIV enzyme is reverse transcriptase huge error rate Result of that is numerous mutations very mutable virus so many different strains the virus Challenge for vaccine is trying to find a vaccine that will work on every strain of Patient was vaccinated against a specific strain 30 days later it was found that the virus they currently had was 12 different than the original strain Second infection by second strain of HIV 12 different even though fairly similar the immune system effective against first strain could not suppress infection of the second strain Take hoe Traditional vaccine approach must tackle the HUGE genetic diversity of HIV strains that exist How Antibodies in AIDS Vaccine Would Work Models predict that an AIDS vaccine with 50 efficacy given to 30 of the population would avert 5 6 million new infections in low and middle income countries between 2015 and 2030 Roughly 24 of the infections that would otherwise occur Problems with Creating an AIDS Vaccine We know from history that no major viral epidemic has ever been defeated without a vaccine Upon penetrating the cd4 cells HIV inserts its genetic material and hijacks the cell s mechanisms to create more viruses as well as creating a reservoir of infection By stimulating an immune response a vaccine could actually spur further virus production The virus s high mutation rate increases the chance that one or two mutations could escape the immune response stimulated by the vaccine and that the vaccine resistant virus could be transmitted to others Researchers must develop multiple vaccines or one that works broadly across multiple subtypes In 30 years of the AIDS pandemic only one individual has rid himself of the virus Preventive Therapeutic Vaccines Preventative vaccine no infection Chronic infection disease Chronic infection therapeutic vaccines and antimicrobials no disease Medical News Therapeutic AIDS Vaccine Said Promising They tested a vaccine that while it did not cure the infected monkeys it did reduce the amount of virus that was in their system Therapeutic Vaccines patient The hope of finding a preventive vaccine sterilizing immunity is dwindling Therapeutic vaccines prevent disease rather than infection treat the HIV Antibodies induced by the vaccine would reduce viral load making patients less likely to spread HIV and lead to production of T cells to fight HIV Therapeutic vaccines will prolong life promote disease free period prvent progression to AIDS and significantly lower viral load Therapeutic vaccines could protect the offspring of infected women by reducing viral load in blood stream Why Vaccines Can Pay Off Monthly medicals costs can range from 2 000 to 5 000 Lifetime cost of treating HIV is more than 500 000 What is the Alternative to a Vaccine Expanded access to treatment Many proven and yet to be proven preventive measures For example Engineering white blood cells to have mutated CCR5 This resembles immunotherapy for Leukemia Prevention efforts have largely rested on the formula of A B C abstinence from sex being faithful and using condoms Lack of knowledge about the virus and its transmission has resulted in a surge of
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