What is the pathophysiology of early symptomatic HIV infection?

Updated: Jan 02, 2020
  • Author: Robert J Carpenter, DO, FACP; Chief Editor: John Bartlett, MD  more...
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On day 0, the individual is exposed to HIV, and infection begins.

Day 8

On about day 8, the virus is detectable in blood using antigen tests such as polymerase chain reaction (PCR); however, antibody test findings are negative. The amount of virus in the blood more than doubles every day. The CD4 cell count (and total white blood cell count) begins to drop as the viral load increases.

Weeks 2-4

During weeks 2-4, early antibodies to HIV may be detected; however, they have a low affinity for viral antigens and have little effect on the virus itself. Newer antibody assays may detect these antibodies. The viral load peaks and begins to decline as the immune system begins to battle the virus with antibodies and CD8 cytotoxic cells.

Although persons infected with HIV may transmit the infection to another person at any time, they are highly infectious during the period of acute infection when genital shedding of HIV virus peaks, which occurs at approximately week 3-4 of acute infection. The individual may be asymptomatic during this period and thus may have no knowledge that he or she is infected and so may not use appropriate safer-sex precautions. This represents an epidemiologic challenge in controlling the HIV pandemic.

Weeks 10-24

During weeks 10-24, the HIV viral load drops to its lowest point, also known as the set point, which is different in each person. Antibodies now have higher affinity for viral antigen; therefore, antibody tests become positive for HIV. Seroconversion is now complete, and chronic HIV infection begins.

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