The Immune System
To understand HIV, we first have to have a basic understanding of the body's immune response.With each breath we take, with every meal we eat, foreign bacteria enter our body. Most of these are trivial and harmless. However, some can and do cause illnesses such as the common cold, TB, hepatitis or the chickenpox. But we aren't defenseless against these invaders. The body has a complex mechanism to fight illness called the immune response.
- When a foreign infectious organism such as a bacteria or a virus enters the body our immune system goes to work.
- Specialized cells find the organism and begin to multiply in order to fight off the attacker. These cells produce substances called antibodies, which fight off any possible infection caused by the foreign attacker.
- The antibodies remain in the body for life, protecting a person from future exposures to that organism.
The remarkable thing about the immune system is that our cells are very specific in what invaders it will fight. Our cells are encoded with a template that allows them to only attack those organisms that specifically fit their template. In other words, these specialized cells float around laying dormant until they bump into the organism that fits the template they carry. Only then will they begin the immune response and antibody production.
How Stress Affects the Immune System
How Do Vaccines Help
Vaccines help the body's immune system by tricking the body into thinking the vaccine is an infectious intruder. The immune system's specialized cells bump into the vaccine proteins and begin to produce antibodies. Weeks or months later, if a person does get exposed to an organism they were vaccinated against, the antibodies are already in the body, fighting off the attacker before it can cause illness. For example:- a flu vaccine tricks the body into thinking it has been infected with the flu virus. The immune response immediately begins to produce antibodies to fight off the flu. Later, when the person really gets exposed to the flu virus, the antibodies are already there and prevent the person from getting sick with the flu.
Vaccines are routinely given to HIV infected people to help their body produce antibodies to fight off potentially serious infections such as the flu, Hepatitis A, Hepatitis B, and a specific pneumonia called pneumococcal pneumonia. Most vaccinations are good for a lifetime, only needing a booster to remain effective. The exception to this rule is the flu vaccine. Because the virus that causes the flu changes from year to year, a new vaccine specific to the changed virus must be given each year to prevent becoming sick with the flu.
These are the most common vaccines given:
- Flu (influenza)
- Hepatitis A
- Hepatitis B
- Pneumovax (pneumococcal pneumonia)
- Tetanus
Get Screened for TB - The PPD Test
The PPD is a screening test that identifies a tuberculosis (TB) exposure sometime in the lifetime or the person being tested. A small amount of serum containing TB is injected under the skin. After 72 hours the test is read, sometimes by the patient but most often by a person trained in TB test reading.- A negative test
There is no localized reaction characterized by redness, swelling, or a hard lump at the site of the PPD test. - A positive test
indicated by a swollen, red, large raised area where the intradermal serum was injected.
A positive test does not mean a person has an active TB infection. It does mean that the person has been exposed to TB sometime in their lifetime and their body has produced antibodies to fight the TB. If a person does have a positive PPD, an appointment needs to be made with his or her physician to further examine the patient for signs of active TB infection and to plan preventative treatments. A PPD should be done yearly unless a person has had a previous positive test. In that case, a chest x-ray is done regularly to assess for active TB infection.
