Because people newly infected with HIV often show few symptoms and signs of seroconversion illness, relying on such often nonspecific markers is a poor way to detect early infection with the virus in clinics, MedPage Today reports. Publishing their findings in the New England Journal of Medicine, researchers conduced twice-weekly blood tests of 2,276 high-risk individuals in Uganda, Kenya, Tanzania and Thailand.

An individual is acutely infected with HIV when he or she tests positive for HIV RNA or the p24 antigen (each of which shows up in the body before antibodies to the virus) but tests negative for antibodies.

A total of 261 members of the cohort tested positive for HIV RNA, and 112, or 3.4 percent of the cohort, had their HIV status confirmed. Out of that group, 50 people gave two or more samples of blood that tested positive for HIV RNA before they tested positive for antibodies as well. The study’s analysis focused on this group.

The median peak viral load among the group was 5 million, occurring 13 days after the first positive test of HIV RNA. After the first RNA-positive test, a median 14 days passed before individuals tested positive for antibodies. After peaking, the viral load hit a low point of 20,000, which was close to the viral load’s ultimate plateau of 25,000.

Most commonly, physical symptoms of acute HIV, also known as seroconversion illness, took place around the time of the viral load peak. The most commonly reported symptoms were fever, headache and malaise. The most common signs the doctors observed were high heart rate and swollen lymph nodes. Participants reported a median of one symptom of acute infection at a median of two study visits. Physicians observed one sign of acute infection at a median of three visits.

The researchers concluded: “Nonspecific symptoms and signs [of acute HIV] were most common, severe manifestations were not observed, volunteers reported symptoms in only 29 percent of visits, and on any given visit day the likelihood of observing a symptom or sign was only 50 percent.”

To read the MedPage Today article, click here.

To read the study abstract, click here.