Cliff Abdul Magwira

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Cervical cancer remains a major health burden among women in sub-Saharan Africa, where screening is often limited. Persistent high-risk human papillomavirus (HR-HPV) infection is the principal cause, highlighting the need for accurate molecular diagnostics. This cross-sectional study evaluated the analytical performance of one mRNA assay, APTIMA^® HPV assay (APTIMA mRNA), and two DNA-based assays, the Abbott RealTime High Risk HPV assay (Abbott DNA) and Seegene Allplex™ II HPV28 assay (Seegene DNA), in 527 cervical samples from a South African tertiary hospital, focusing on 14 shared HR-HPV genotypes. Seegene DNA yielded the highest detection rate (53.7%), followed by Abbott DNA (48.2%) and APTIMA mRNA (45.2%). APTIMA mRNA showed a strong agreement with Abbott DNA (87.9%, κ = 0.80), 89.9% sensitivity, 91.2% NPV, and the highest accuracy (AUC = 0.8804 vs. 0.8681). The agreement between APTIMA mRNA and Seegene DNA was moderate (83.4%, κ = 0.70), reflecting target differences. Many DNA-positive/mRNA-negative cases likely represent transient infections, though some may be latent with reactivation potential, warranting a follow-up. In resource-constrained settings, prioritizing transcriptionally active infections through mRNA testing may enhance screening efficiency and reduce burden. Scalable, cost-effective assays with strong clinical utility are essential for broadening access and improving cervical cancer prevention. Further studies should assess the integration of mRNA testing into longitudinal screening algorithms.

Cervical cancer remains a leading cause of cancer-related morbidity and mortality among women in sub-Saharan Africa, where screening access is limited. It is mainly caused by persistent high-risk human papillomavirus (HR-HPV) infection, making HPV testing in screening programs imperative. The widely used DNA-based assays cannot distinguish transient from active infections, thus reducing specificity and risking overtreatment. In contrast, mRNA-based assays like APTIMA® detect E6/E7 transcripts, markers of active, likely persistent infections and improve clinical relevance. This cross-sectional study compared mRNA and DNA assay performance and characterized circulating HPV genotypes in a South African population to inform screening approaches in resource-limited settings. 527 cervical samples collected from women at a South African tertiary hospital were tested for HPV infections using two DNA assays (Abbott RealTime High-Risk HPV, Seegene Allplex™ II HPV28) and one mRNA assay (APTIMA® HPV). APTIMA® had the highest specificity (86.2%) and sensitivity (89.9%), outperforming Seegene (81.6%, 82.3%) and demonstrating stronger agreement with Abbott (Cohen’s Kappa = 0.80 vs. 0.70). ROC analysis confirmed APTIMA’s improved discrimination (AUC 0.8804 vs. 0.8681). Although Seegene detected more infections, many were likely transient and clinically insignificant. Findings support mRNA-based testing to better target high-risk women and reduce unnecessary interventions in resource-limited, high-burden settings.

Single filamentous bacteria (SFB) have been shown to prevent murine rotavirus (RV) and other mammalian enteric infections, independent of type I and II interferons, by promoting adaptive and innate immunity through differentiation of intestinal Th17 cells, production of immunoglobulin A and retinoic acid receptor (RAR) signaling. Here, we assessed whether the abundance of the bacterium at the time of oral RV vaccination would impede the vaccine performance. Stool samples were collected from infants a week after RV vaccination to determine vaccine shedders (n = 20) and non-shedders (n = 20). The abundance of SFB and expression of Cathepsin L (CTSL, a biomarker for differentiated Th17 cells), cytokines 17 A and IL-22, and retinoic acid receptor (RAR) were assayed using quantitative PCR. The abundance of SFB was significantly high in non-shedders compared to vaccine shedders, p = 0.042, and correlated negatively with vaccine virus shedding load (R = − 0.69). The expression of CTSL was increased 3.5-fold in non-shedders compared to vaccine shedders, p = 0.035. Similarly, the expression of IL-17 A and IL-22 was increased 8.5- and 12-fold, respectively, in non-shedders versus shedders. The expression of RAR was also consistent with the abundance of SFB, as it increased 5.9-fold in non-shedders compared to vaccine shedders, p = 0.034. Logistic regression analysis indicated that Infants possessing increased abundance of SFB were less likely to shed the vaccine in stool samples (OR = 0.31, 95% CI = 0.102–0.962), p = 0.043. Taken together, our observations suggest that the abundance of SFB at the time of vaccination may impede the oral RV vaccine take in the study population.

Background: The metabolism of nutritional iron, required by viruses to replicate and proliferate, is regulated by hepcidin, a peptide hormone of 25 amino acids. Overexpression of hepcidin results in iron deficiency anemia (IDA), while its downregulation can lead to an iron overload. Recently, IDA has been highlighted for its role in the impairment of adaptive immunity and poor vaccine effectiveness. Here, we assessed the possible role of IDA in oral rotavirus (RV) vaccine take among South African infants.Methodology: Paired stool and unstimulated saliva were collected from oral RV vaccinated infants, who attended a routine immunization program at Oukasie Healthcare clinic, north of Pretoria, South Africa, to decide vaccine shedders (n = 20) and non-shedders (n = 18). IDA was determined by assaying the salivary hepcidin levels using an ELISA kit, while expression of hepcidin, hepcidin inducer IL-6, Interferon I (IFN I) and IFN-γ were determined by qPCR.Results: There were no significant differences in the average hepcidin levels between vaccine shedders and non-shedders (p = 0.83). Hepcidin levels were decreased 0.43-fold a week after vaccination versus pre-vaccination, p = 0.0001. Unlike the concentration, the expression of hepcidin increased 5-5-fold in non-shedders compared to vaccine shedders. Similarly, the expression of IL-6 and IFN I were increased 5.2- and 4.9-fold, respectively, in non-shedders compared to shedders. In contrast, the expression of IFN-γ was increased 3.2-fold in shedders compared to non-shedders.Summary: Collectively, our observations suggest a possible role for IDA in impediment of oral RV vaccine take among South African infants.

Bacterial lipopolysaccharides (LPS) have been shown to promote enteric viral infections. This study assessed whether possessing elevated levels of LPS was associated with norovirus infection. Fecal samples from diarrheic norovirus-positive (DNP) (n = 26), non-diarrheal norovirus-negative (NDNN) (n = 26), asymptomatic norovirus-positive (ANP) (n = 15), and diarrheic norovirus-negative (DNN) (n =15) infants were assayed for selected bacterial LPS by quantitative PCR. The mean levels of selected LPS gene targets were significantly high in DNP infants (6.17 ± 2.14 CFU/g) versus NDNN infants (4.13 ± 2.25 CFU/g), p = 0.003. So too was the abundance between DNP and DNN infants (p = 0.0023). The levels of selected LPS gene targets were high regardless of whether the infection was symptomatic or asymptomatic, p = 0.3808. The average expression of genes coding for selected LPS and their signalling molecule, Toll-like receptor 4 (TLR4), increased 7- and 2.5-fold, respectively, in DNP versus NDNN children. Infants possessing elevated levels of selected LPS-rich bacteria were 1.51 times more likely to develop norovirus diarrhea (95% CI: 1.14–2.01, p = 0.004). In conclusion, norovirus infection was associated with abundance of selected bacterial LPS, suggesting a possible role of bacterial LPS in norovirus infection.

Bacterial flagellin, a potent intestinal innate immune activator, prevents murine rotavirus (RV) infection independent of adaptive immunity and interferons. The flagellin-induced immunity is mediated by Toll-like receptor (TLR5) and Nod-like receptor C4 (NLRC4), which elicit the production of interleukins 22 (IL-22) and IL-18, respectively. Here, we assessed whether a high abundance of flagellin at the time of vaccination would negatively affect the oral RV vaccine take. Fecal samples were collected from infants a week after first dose of Rotarix vaccination to establish vaccine shedders (n = 50) and non-shedders (n = 44). The abundance of flagellin and expression of flagellin-encoding fliC, TLR5 and NLRC4, IL-22 and IL-18 genes was determined by qPCR. There were no differences in the abundance of flagellin between vaccine shedders and non-shedders (p = 0.15). However, the expression of FliC was increased 7.5-fold in non-shedders versus shedders (p = 0.001). Similarly, TLR5 (p = 0.045), and not NLRC4 (p = 0.507,) was significantly expressed in non-shedders versus shedders. The expression of IL-22 (p = 0.054), and not IL-18 dependent NLRC4 (p = 0.650), was increased 3.4-fold in non-shedders versus shedders. Collectively, our observations suggest a possible negative impact of the abundance of viable flagellated bacteria at the time of vaccination on the replication and therefore the performance of RV vaccines.

Bacterial flagellin, a potent intestinal innate immune activator, prevents murine rotavirus (RV) infection independent of adaptive immunity. The flagellin-induced immunity is mediated by Toll-like receptor (TLR5) and Nod-like receptor C4 (NLRC4), which elicit the production of interleukins 22 (IL-22) and IL-18, respectively. Here, we assessed whether a high abundance of flagellin at the time of vaccination would negatively affect the RV vaccine take. Fecal samples were collected from infants at 7 days post first dose of Rotarix vaccination to establish (a) vaccine shedders (n = 50) and (non-shedders (n = 44). QPCR was used to assay the abundance of flagellin and expression of flagellin-encoding fliC, TLR5, NLRC4, IL-22 and IL-18 genes. There was no difference in abundance of flagellin between vaccine shedders and non-shedders ( p = 0.15). However, the expression of FliC was increased 7.5-fold in non-shedders versus shedders ( p = 0.001). Similarly, TLR5 ( p = 0.045), and not NLRC4 ( p = 0.507,) was significantly expressed in non-shedders versus shedders. The expression of IL-22 ( p = 0.054), and not IL-18 dependent NLRC4 ( p = 0.650), was increased 3.4-fold in non-shedders versus shedders. Collectively, our observations suggest that the abundance of viable flagellated bacteria at the time vaccination can negatively impact the performance of RV vaccines.

Bacterial lipopolysaccharides (LPSs) have been shown to promote enteric viral infections. This study tested the hypothesis that elevated levels of bacterial LPS improve oral rotavirus vaccine replication in South African infants. Stool samples were collected from infants a week after rotavirus vaccination to identify vaccine virus shedders (n = 43) and non-shedders (n = 35). Quantitative real-time PCR was used to assay for selected LPS-rich bacteria, including Serratia marcescens, Pseudomonas aeruguinosa and Klebsiella pneumonia, and to measure the gene expression of bacterial LPS, host Toll-like Receptor 4 (TLR4) and Interleukin-8 (IL-8). The abundance of selected LPS-rich bacteria was significantly higher in vaccine shedders (median log 4.89 CFU/g, IQR 2.84) compared to non-shedders (median log 3.13 CFU/g, IQR 2.74), p = 0.006. The TLR4 and IL-8 gene expressions were increased four- and two-fold, respectively, in vaccine shedders versus non-shedders, but no difference was observed in the bacterial LPS expression, p = 0.09. A regression analysis indicated a significant association between the abundance of selected LPS-rich bacteria and vaccine virus shedding (Odds ratio 1.5, 95% CI = 1.10–1.89), p = 0.002. The findings suggest that harbouring higher counts of LPS-rich bacteria can increase the oral rotavirus vaccine take in infants.

Several risk factors have been associated with SARS-CoV-2 infections and severity of COVID-19 disease it causes. This study investigated whether variations in histo-blood group antigen (HBGA) expression can predispose individuals to SARS-CoV-2 infections and severity of the disease. Nasopharyngeal swabs, randomly selected from SARS-CoV-2 positive and SARS-CoV-2 negative individuals, were tested for Lewis and H-type 1 HBGA phenotypes by ELISA using monoclonal antibodies specific to Lewis a, Lewis b and H type 1 antigens. The most common Lewis HBGA phenotype among all study participants was Lewis a⁻b⁺ (46%), followed by Lewis a⁻b⁻ (24%), Lewis a⁺b⁻ and Lewis a⁺b⁺ (15% each), while 55% of the study participants were H-type 1. Although SARS-CoV-2 negative individuals had a lower likelihood of having a Lewis a⁻b⁻ phenotype compared to their SARS-CoV-2 positives counterparts (OR: 0.53, 95% C.I: 0.255–1.113), it did not reach statistical significance (P = 0.055). The frequency of Lewis a⁺b⁺, Lewis a⁺B⁻, Lewis a⁻b⁺, H type 1 positive and H type 1 negative were consistent between SARS-CoV-2 positive and SARS-CoV-2 negative individuals. When stratified according to severity of the disease, individuals with Lewis a⁺b⁻ phenotype had a higher likelihood of developing mild COVID-19 symptoms (OR: 3.27, 95% CI; 0.9604–11.1), but was not statistically significant (P = 0.055), while Lewis a⁻b⁻ phenotype was predictive of severe COVID-19 symptoms (OR: 4.3, 95% CI: 1.274–14.81), P = 0.016. In conclusion, individuals with Lewis a⁻b⁻ phenotype were less likely to be infected by SARS-CoV-2, but when infected, they were at risk of severe COVID-19.