Published in PLOS One on 2025-11-19, this study is presented as an attributed evidence briefing. The excerpts below are the original researchers’ words, reproduced under their Creative Commons Attribution licence. Health Signal has selected the abstract and, where needed, opening background paragraphs; the complete methods, results, limitations and references remain in the linked paper.
Original authors: Nonhlanhla Khumalo, Avumile Mankahla, Stephen Korsman, Freedom Gumedze, Wisdom Basera, Anthia Ndyenga, Lwazi Mhlanti, Mashiko Setshedi, Ruanne Barnabas, C. Wendy Spearman, Mark W. Sonderup
Source: PLOS One • DOI 10.1371/journal.pone.0336213
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
The most frequent transmission modes of blood-borne infections (BBI), including HIV, hepatitis B virus (HBV) and C (HCV), are well documented. South Africa, an HIV epicentre, with HBV endemicity and an additional HCV burden, raises the possibility of novel transmission means. A unique style of close shave haircut that can elicit folliculitis keloidalis nuchea (FKN), may produce bleeding during haircuts and possible BBI transmission. We designed a prospective case control study to evaluate the potential risk of BBI transmission.
Men with FKN and non-FKN controls were recruited from 2 centres in South Africa, Cape Town and Mthatha. The presence of FKN was diagnosed by a dermatologist and clinical photographs independently corroborated by 3 other dermatologists not involved in the study. A comprehensive confidential questionnaire was administered to each participant interrogating risk factors for potential HIV, HBV, and HCV infection. Each participant was screened for HIV 1/2 (Alere Determine), HBsAg (Alere Determine) and HCV antibody (SD Bioline) using point of care tests. Positive HIV screens were confirmed with a second test, Vikia HIV 1/2 test (bioMerieux). Logistic regression analysis adjusting for the relevant confounder was used to assess the associations.
A total of 1163 men, median age 33.4 years [IQR 27.8–42.0], were evaluated. Those who screened positive for any viral infections were significantly older than those who did not, 37.1 [IQR 31.0–44.4) vs. 32.3 [IQR 26.9–41.0] years, p < 0.001, respectively. Overall, the seroprevalence of HIV, HBV, and HCV, was 17.2%, 6.9% and 0.4%, respectively. There was no significant difference in seroprevalence for these potential BBIs between those with FKN and without, p = 0.33, 0.66 and 0.29, respectively. For HIV co-infection with HBV and HCV, findings were similar, p = 0.64 and 0.51, respectively. When controlled for whether participants knowingly bleed during haircuts, HIV seropositivity was significantly more likely in those who regularly bleed, OR = 2.51 [95% CI 1.16–5.42], p = 0.02. Other transmission risk factors for HIV, were also significantly more likely – reported sexually transmitted genital lesions or discharge, aOR = 1.58 [95% CI 1.13–2.22], p = 0.01; and a tattoo/piercing informally done, aOR = 1.84, [95% CI 1.13–2.22], p = 0.01. Similarly, although overall HCV seroprevalence was low, those HIV/HCV co-infection was more likely in those who usually bleed with a haircut, aOR = 2.43; [95% CI 1.13–5.25]; p = 0.02, those with a sexually transmitted genital lesion or discharge, aOR = 1.58 [95% CI 1.13–2.21]; p = 0.01 and those with a tattoo/piercing informally done, aOR = 1.85 [95% CI 1.27–2.72]; p < 0.01. This was not so for HBV mono-infection, p = 0.89. Overall rates of known and recorded HBV vaccination in childhood were low, however in those with no viral infection, the rate of known vaccination was higher, 25.0% vs. 16.2%; p = 0.01 respectively.
Reading this evidence
Use the full paper to check the study design, participant selection, comparator and outcome definitions before drawing a practical conclusion. An association does not by itself show cause and effect. A reported performance measure needs its denominator and uncertainty. A finding from a particular facility, sample or time period should retain that scope when it is discussed elsewhere.
This briefing makes the source accessible within the wider technology & industry desk. It does not assess an individual patient or certify a product. When considering relevance to another health system, examine the original authors’ account of context and limitations, then seek local implementation evidence. The related reporting below provides other studies to read alongside this one; it is a topic connection, rather than a claim that their results are directly comparable.
© 2025 Nonhlanhla Khumalo, Avumile Mankahla, Stephen Korsman, Freedom Gumedze, Wisdom Basera, Anthia Ndyenga, Lwazi Mhlanti, Mashiko Setshedi, Ruanne Barnabas, C. Wendy Spearman, Mark W. Sonderup. Excerpts reproduced under CC BY. Selection, formatting and contextual notes by Health Signal. The researchers are the authors of the source study, not members of Health Signal’s staff.
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