Clinical

Prevalence of HIV infection among tissue and blood donors in US is under 0.1%

Last Updated: 2004-08-18 17:00:26 -0400 (Reuters Health)

NEW YORK (Reuters Health) - The prevalence of positive screening tests for HIV in blood and tissue donation samples in the US between 2000 and 2002 was just less than 0.1%, according to a new study, and the prevalence of hepatitis C virus (HCV) was just over 1%.

Findings from two studies reported in the August 19th issue of The New England Journal of Medicine help clarify the risk of transmitting HIV and other viral pathogens with tissue and blood donation in the US. Both studies indicate that nucleic acid amplification testing can help reduce the risk of these infections.

In the first study, Dr. Shimian Zou, from the American Red Cross in Rockville, Maryland, and colleagues analyzed data from 11,391 tissue donors at various centers between 2000 and 2002 to assess the probability of undetected viremia with HIV, hepatitis B virus (HBV), HCV, and human T-lymphotropic virus (HTLV). These rates were compared with those seen in first-time blood donors.

The researchers determined that the prevalence of positive screening was 0.093% for HIV-1, 0.299% for HBV, 1.091% for HCV, and 0.068% for HTLV. The corresponding estimated incidence rates were 30.1, 18.3, 12.3, and 5.6 per 100,000 person-years.

Based on these findings, the probability of viremia at the time of tissue donation ranged from 1 in 34,000 for HBV to 1 in 128,000 for HTLV. The probability of viremia at tissue donation for HIV was 1 in 55,000.

The prevalence rates for these four infections among tissue donors are lower than in the general population, the investigators point out. However, tissue donors are more likely than blood donors to have undetected viremia at the time of donation.

"The addition of nucleic acid-amplification testing to the screening of tissue donors should reduce the risk of these infections among recipients of donated tissues," the investigators note.

In the second study, Dr. Susan L. Stramer, from the American Red Cross in Gaithersburg, Maryland, and colleagues used nucleic acid-amplification testing to evaluate the rate of HIV-1 and HCV infections among antibody-negative donors. More than 37 million units of blood were screened.

Twelve units were confirmed as containing HIV-1 RNA, yielding a rate of 1 contaminated unit per 3.1 million donations. Only two of these units were identified with HIV-1 p24 antigen testing. The rate for HCV was 1 contaminated unit per 230,000 donations.

Specimens from first-time donors were 3.3- and 4.1-times more likely than those from repeat donors to test positive for HCV and HIV, respectively. Testing in 67 HCV RNA-positive donors revealed a median period of 35 days between index donation and seroconversion.

"Minipool nucleic acid-amplification testing has helped prevent the transmission of approximately 5 HIV-1 infections and 56 HCV infections annually and has reduced the residual risk of transfusion-transmitted HIV-1 and HCV to approximately 1 in 2 million blood units," the researchers comment.

N Engl J Med 2004;351:751-768.