If HIV gets into the bloodstream from a needle stick directly into a vien or artery, then there might be just one or ten or 100 virions in the blood at the time of the event. But if HIV gets into the bloodstream from a mucosal surface and then replicates in germinal centers and lymph nodes for days or weeks before entering the blood it is a very different situation. But anyway, post-exposure prophylaxis can work in many cases, but not all cases. Some drugs leave the bloodstream and enter different tissues at different rates than other drugs.

It depends on what you mean by "in the bloodstream" and for how long, etc... There is good evidence that we can prevent infections after needlestick injuries by giving antiretroviral therapy within 24 hours of the needlestick. But even that depends on how much blood was on the needle and how deep the needle jabbed into the recipient etc... There is also solid evidence that post-exposure prophylaxis is effective with sexual exposures to the virus.

https://www.ncbi.nlm.nih.gov/pubmed/?term=immunodeficiency+post-exposure+prophylaxis

Article Antiretrovirals for Primary HIV Prevention: The Current Stat...

https://www.health.ny.gov/publications/0213.pdf

Unfortunately yes.

If the virus has been in contact with body fluids, antiviral therapy is severely effective in early hours. but if it enters the bloodstream system, the likelihood of the success of antiretroviral drugs in the absolute inhibition of the virus is significantly reduced. Anyway, I think, post-exposure prevention is highly obligatory.

Dear Brian Thomas Foley,

Thank you for your answer.

I mean by "in the bloodstream", in "the flow of blood that moves through the heart and body" as it is in the dictIonary

In case of prevention the virus always meets the anti-HIV medications in the bloodstream so the result can not be perfect. Do you agree?

Prevention can take many forms. Once this person is linked to treatment and is adherent to it, once viral load is reduced, the possibility of transmission to others is markedly reduced (one form of prevention). In addition, treatment will prevent the development of immunedeficiency in most cases (another form of prevention).

It depends on the amount of the virus in the blood sample - i.e. viral load, and the immune system. ARVs or PREP are effective in suppressing the viral load and thus infection. All dependent on time between infection and prophylactic treatment; the immune system of the person becoming infected, and the amount of the virus in the blood sample that is transmitted.

If HIV gets into the bloodstream from a needle stick directly into a vien or artery, then there might be just one or ten or 100 virions in the blood at the time of the event. But if HIV gets into the bloodstream from a mucosal surface and then replicates in germinal centers and lymph nodes for days or weeks before entering the blood it is a very different situation. But anyway, post-exposure prophylaxis can work in many cases, but not all cases. Some drugs leave the bloodstream and enter different tissues at different rates than other drugs.

Thank you for the detailed and exact answers.Today any kind of HIV/AIDS prevention needs anti HIV medication and good luck.

But, for example, in case of vaginal HIV infection, if we could stop the infection in the vagina that would be perfect prophylaxis

I have an idea but do not have the money to check it.

Prevention is time sensitive and also depends on the extent of infection. Early initiation of ARV post exposure can reduce the virus to undetectable levels.

Article Technologies for HIV prevention and care: Challenges for hea...

Its not late, start at any state you get to know about it.

I think you are right. But when the virus is in the bloodstream then the treatment seems to be necessary during the rest of life. Is it prevention?

I thought you could still prevent yourself from acquiring different strains of HIV and thus prevention still remains relevant. In addition, PEP remains useful and effective upto 72 hours of exposure