Seroconversion illness

Seroconversion typically occurs two to twelve weeks after infection and may be associated with a flu-like illness. The most commonly reported symptoms include:

• Fever.

• Rash.

• Aches and pains.

• Oral ulcers.

• Sore throat.

• Weight loss of more than 2.6kg.

• Fatigue.

• Nausea.

Fever and rash together, as well as loss of weight and appetite are the most strongly predictive symptoms of HIV seroconversion illness, according to a study carried in San Francisco (Hecht 2002; Vanhems 1999). It is unclear if the presence of a larger number of these symptoms is a stronger predictor of HIV seroconversion. The duration of the illness and the severity of the symptoms are associated with a higher viral load during and just after seroconversion (Lavreys 2002).

It is thought that somewhere between 50 and 80% of newly infected people will experience most or all of these symptoms. A smaller proportion may develop diarrhoea, ulceration of the mouth, throat or genitals, anorexia or swollen lymph nodes (Clark 1991). Weight loss, abdominal pain, loss of appetite, oral thrush and neurological abnormalities have also been reported as symptoms of seroconversion (Vanhems 1999).

A study of seroconverters in Zambia has suggested a slightly different profile for seroconversion illness. Influenza, rash and sore throat were not linked to HIV seroconversion. Instead, malaria, diarrhoea, swollen glands, inflammation, night sweats and weakness were associated with HIV seroconversion (Fideli 2003). A study of women in Uganda and Zambia has also shown that women with acute or early HIV infection are more likely to have fever, severe headaches, abdominal pain, pelvic tenderness, fatigue, abnormal vaginal discharge and itching and abnormalities of the vagina and cervix than HIV-negative women, along with an increased incidence of vaginal infections (Morrison 2004). These studies may point to regional or ethnic differences in the nature of seroconversion illness.

There is some evidence that people who experience symptoms during primary infection tend to have a more rapid rate of disease progression than people who have few or no symptoms upon initial infection with HIV. See Viral load, CD4 cell counts and other tests: Other markers for further discussion of the prognostic significance of seroconversion illness.

Until recently it was thought that HIV remains concentrated in the lymph nodes during early infection, replicating in very large numbers and infecting more CD4 T-cells. While this is partly true, recent studies have shown that after the first six days of infection the virus spreads to infect huge numbers of T-cells in the lining of the bowel. Here as many as 60 to 80% of memory CD4 T-cells may be destroyed in the first 17 days of infection (Johnson 2005; Mattapallil 2005). However during this earliest stage of infection and for the first months or years afterwards swollen lymph nodes are often the only clinical feature seen in a person with HIV infection.