Related Experiment Video
Updated: Feb 10, 2026

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture
Published on: October 12, 2018
Repeat Human Immunodeficiency Virus Testing by Transmission Risk Group and Rurality of Residence in North Carolina
Rachael M Billock, Erika Samoff1, Anna B Cope2
1Communicable Diseases Branch, North Carolina Department of Health and Human Services, Raleigh.
Background:
Understanding of repeat human immunodeficiency virus (HIV) testing (RHT) is limited and the impact of rural residence as a potential barrier to RHT is unknown. Rural populations are of particular interest in the Southeastern United States because of their disproportionate HIV burden.
Methods:
We used HIV surveillance data from publicly funded HIV testing sites in North Carolina to assess repeat testing by transmission risk group and residential rurality in a retrospective cohort study. Linear binomial regression models were used to estimate adjusted, 1-year cumulative incidences and cumulative incidence differences comparing RHT within transmission risk populations by level of rurality.
Results:
In our total study population of 600,613 persons, 19,275 (3.2%) and 9567 (1.6%) self-identified as men who have sex with men (MSM) and persons who inject drugs (PWID), respectively. A small minority, 13,723 (2.3%) resided in rural ZIP codes. Men who have sex with men were most likely to repeat test (unadjusted, 1-year cumulative incidence after an initial negative test, 16.4%) compared with PWID (13.2%) and persons who did not identify as either MSM or PWID (13.6%). The greatest effect of rurality was within PWID; the adjusted, 1-year cumulative incidence of RHT was 6.4 (95% confidence interval, 1.4-11.4) percentage points higher among metropolitan versus rural PWID.
Conclusions:
One-year cumulative incidence of RHT was low among all clients of publicly funded HIV testing sites in North Carolina, including MSM and PWID for whom annual testing is recommended. Our findings suggest a need for public health efforts to increase access to and support for RHT, particularly among rural PWID.
Related Concept Videos
Immunodeficiency Diseases
There are three main causes of immunodeficiency...
What are Viruses?
Relative Risk
Noncompartmental Analysis: Mean Residence Time
After the administration of a drug through intravenous bolus injection, the drug molecules are distributed throughout the body and remain there for varying periods. The MRT represents the average time these drug molecules stay in the...
Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
Design of Transmission Shafts

