How the vaccine to fight HIV/AIDS is developed
May 14, 2010
A vaccine is a substance that is introduced into the body to prevent infection caused by any disease-causing organism, such as a virus, bacteria or parasite.
A vaccine is a substance that is introduced into the body to prevent infection caused by any disease-causing organism, such as a virus, bacteria or parasite.
“It teaches the body how to defend itself against an invader by creating an immune response,†Dr Annet Nanvubya of UVRI, says.
Types of vaccines
There are different types of vaccines; preventive and therapeutic vaccines.
A preventive vaccine is designed for individuals who are not infected with the targeted disease.
Weakened bacteria or viruses are injected into a person to provoke the body to produce antibodies to fight the invaders.
These antibodies expel the bacteria and remain in the body looking out for a similar invader, thus preventing the individual from becoming infected for a long time.
A therapeutic vaccine is given to infected individuals to form immune responses that would allow better control of the infection or disease. In case of HIV, it slows the disease from progressing to AIDS.
HIV vaccine
Unlike other vaccines where weakened germs are used, no HIV is used in AIDS vaccines.
They use a synthetic virus, made in the laboratory, which cannot cause HIV infection. The vaccine does not contain any material from HIV infected individuals.
But the replica of the virus made is still able to convince our soldiers that there is an invasion of an enemy looking like the virus and this triggers off a variety of defence mechanisms that help the body fight against HIV.
According to IAVI documents, it starts with a biological concept. Experts in how our immune system works suggest ways in which an HIV virus can be stopped.
These are discussed by many experts and polished. The convincing idea is then tested in a laboratory.
Even when it fails at this stage, new information is learnt about the behaviour of HIV and our immune system.
When it succeeds, it goes to another level of testing it in animals. Normally, scientists use rats, rabbits and monkeys.
This gives the researchers an idea of the effects the candidate is likely to have in humans. Success at this stage is seen in terms of safety and effectiveness in stopping the disease,
When a vaccine candidate succeeds in animals, it is then approved for use among humans.
These clinical trials go through three phases. The first phase is conducted in a small number of low risk and healthy individuals to evaluate the vaccine’s safety and, to a small extent, effectiveness. This may last between 12-18 months.
When it succeeds, it is then taken to the second phase. Here, it tested on many people, up to several hundred participants.
Researchers want to identify common short-term side effects and information on its effect on the immune system. The trials may last between 12-18 months.
Success at this level is not all. The vaccine candidate has then to be tried on a third phase.
These are large clinical trials conducted on several hundreds to several thousands of high risk individuals and may last between 3-5 years. For the vaccine to succeed, it must produce a desired clinical effect against the disease or invader and must also be safe to human beings.
Many vaccines we use today, like the TB, Polio, measles or small pox vaccine went through the same process. The difference is that they used a weakened or disabled germ to trigger off an immune response.
A weak TB germ for example, is introduced in the body. Our defences identify it and kill it easily. But in the process, they reproduce lots of soldiers to remain on alert to fight the same germ in case it returns into the body.
“It teaches the body how to defend itself against an invader by creating an immune response,†Dr Annet Nanvubya of UVRI, says.
Types of vaccines
There are different types of vaccines; preventive and therapeutic vaccines.
A preventive vaccine is designed for individuals who are not infected with the targeted disease.
Weakened bacteria or viruses are injected into a person to provoke the body to produce antibodies to fight the invaders.
These antibodies expel the bacteria and remain in the body looking out for a similar invader, thus preventing the individual from becoming infected for a long time.
A therapeutic vaccine is given to infected individuals to form immune responses that would allow better control of the infection or disease. In case of HIV, it slows the disease from progressing to AIDS.
HIV vaccine
Unlike other vaccines where weakened germs are used, no HIV is used in AIDS vaccines.
They use a synthetic virus, made in the laboratory, which cannot cause HIV infection. The vaccine does not contain any material from HIV infected individuals.
But the replica of the virus made is still able to convince our soldiers that there is an invasion of an enemy looking like the virus and this triggers off a variety of defence mechanisms that help the body fight against HIV.
According to IAVI documents, it starts with a biological concept. Experts in how our immune system works suggest ways in which an HIV virus can be stopped.
These are discussed by many experts and polished. The convincing idea is then tested in a laboratory.
Even when it fails at this stage, new information is learnt about the behaviour of HIV and our immune system.
When it succeeds, it goes to another level of testing it in animals. Normally, scientists use rats, rabbits and monkeys.
This gives the researchers an idea of the effects the candidate is likely to have in humans. Success at this stage is seen in terms of safety and effectiveness in stopping the disease,
When a vaccine candidate succeeds in animals, it is then approved for use among humans.
These clinical trials go through three phases. The first phase is conducted in a small number of low risk and healthy individuals to evaluate the vaccine’s safety and, to a small extent, effectiveness. This may last between 12-18 months.
When it succeeds, it is then taken to the second phase. Here, it tested on many people, up to several hundred participants.
Researchers want to identify common short-term side effects and information on its effect on the immune system. The trials may last between 12-18 months.
Success at this level is not all. The vaccine candidate has then to be tried on a third phase.
These are large clinical trials conducted on several hundreds to several thousands of high risk individuals and may last between 3-5 years. For the vaccine to succeed, it must produce a desired clinical effect against the disease or invader and must also be safe to human beings.
Many vaccines we use today, like the TB, Polio, measles or small pox vaccine went through the same process. The difference is that they used a weakened or disabled germ to trigger off an immune response.
A weak TB germ for example, is introduced in the body. Our defences identify it and kill it easily. But in the process, they reproduce lots of soldiers to remain on alert to fight the same germ in case it returns into the body.