Why antibodies must be produced in 6 months


Sir, I've noticed that there seems to be a lot of "worried-well" postings regarding anitbody detection after 6 months. Maybe I'm wrong but, "If no antibodies are produced by the body in a reasonable amount of time, (6 months or less after possible exposure), wouldn't we very quickly feel the symptoms of a failing immune system?" The basis for this observation lies in 1 key fact: HIV replicates very, very rapidly, in the order of several million cells a day, at least. If no antibodies exist to control this rapid replication, all the body's T-cells will be infected pretty soon. A possible comparison might be made for new-born babies that got the virus from their mother, and haven't begun to produce antibodies. In these situations, we know that the baby's health deteriorates rapidly. I would also bet that the very, very rare persons who took longer than 6 months to test positive for antibodies probably took the test again because of obvious symptoms, or have a history of immuno-deficiency problems. In these situations, perhaps an antigen test (P24, PCR) might be recommended. I'd be interested to hear your comments on these


Thank you for your questions and comments.

It is always important to remember that in medicine, nothing is ever absolute or 100%. As for the 6 month period of time to show antibodies, although more than 99% of infected persons will show positive by this time, a small number of people may take longer than the usual 6 months. This can be due to several reasons. One is that some people could just naturally take longer to respond than most other people. Also, if a person were to have another disease of the immune system, their bodies may take longer to respond than the rest of the population. In persons who have KNOWN problems with their immune systems, doing non-antibody tests like p-24 antigen tests, and PCR tests (which look for the genetic material of the virus itself) are options for HIV diagnosis.

When HIV enters the body, the immune system makes an attack against HIV using a multiple array of different "weapons" against HIV. Antibodies are just one arm of the immune system. There are other parts of the immune system which can attack HIV that don't involve antibodies. There is a cellular response against the virus where special immune cells directly attack HIV, and cells infected by HIV. So, your body makes an attack against HIV, even before antibodies are produced. Once antibodies are produced, they become yet another weapon against HIV. So during the time that antibodies havn't yet been produced, your body is already attacking HIV. Antibodies may make the attack more effective, at least in the short term. We're still trying to learn why, over time, your immune system loses the battle against HIV. In some people, the immune system may lose this battle in a few short years. In others, this battle may continue for many years (10 years or more). Studies are still underway to determine why some people's immune systems do a better job than others in the battle against HIV. This is an ongoing, and active area of research. There is also the possibility that some strains of HIV may be more virulent (stronger) against the immune system than other strains.

I have not seen any studies comparing the time to antibody production, and the time to having symptoms associated with AIDS. But we do know that the average period of time from infection to symptoms is 10 years. This is years beyond when antibody production begins. I have also not seen studies looking at the speed of antibody production, and the speed of HIV's damage to the immune system. But there are many, many factors that can be related to the time of infection, and the speed of damage to the immune system.

There are many factors that can determine how fast HIV damages the immune system. But it's much more complicated than just an antibody response against HIV. There are many other parts of the immune system that play a role in the attack against HIV. Unfortunately, there is no simple answer to your questions. But I hope I have given you some additional insight as to the immune systems attack against HIV, and HIV's attack against the immune system.

If you have any further questions, please feel free to call the Centers for Disease Control at 1.800.232.4636 (Nationwide). Rick Sowadsky MSPH CDS