Electronic Theses and Dissertations (Masters)
Permanent URI for this collectionhttps://hdl.handle.net/10539/38221
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Item Validation of Roche immunoassay for severe acute respiratory virus 2/SARS-COV-2 in South Africa(University of the Witwatersrand, Johannesburg, 2023-01) Grove, Jurette Simone; George, Jaya; Mayne, ElizabethBackground: Serology testing is an important ancillary diagnostic to the reverse transcriptase polymerase chain reaction (RT-PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to evaluate the performance of the Roche Elecsys™ chemiluminescent immunoassay (Rotkreuz, Switzerland), that detects antibodies against the SARS-CoV-2 nucleocapsid antigen, at an academic laboratory in South Africa. Methods: Serum samples were collected from 312 donors with confirmed positive SARS CoV-2 RT-PCR tests, with approval from a large university’s human research ethics committee. Negative controls included samples stored prior to December 2019 and from patients who tested negative for SARS-CoV-2 on RT-PCR and were confirmed negative using multiple serology methods (n = 124). Samples were stored at –80 °C and analysed on a Roche cobas™ 602 autoanalyser. Results: Compared with RT-PCR, our evaluation revealed a specificity of 100% and overall sensitivity of 65.1%. The sensitivity in individuals > 14 days’ post-diagnosis was 72.6%, with the highest sensitivity 31–50 days’ post-diagnosis at 88.6%. Results were also compared with in-house serology tests that showed high agreement in majority of categories. Conclusions: The sensitivity at all-time points post-diagnosis was lower than reported in other studies, but sensitivity in appropriate cohorts approached 90% with a high specificity. The lower sensitivity at earlier time points or in individuals without symptomatology may indicate failure to produce antibodies, which was further supported by the comparison against in-house serology tests.Item Understanding SARS-CoV-2 vaccine hesitancy among pregnant women in Soweto, South Africa: A qualitative study(University of the Witwatersrand, Johannesburg, 2024) Zungu, Zwile; Myburgh, NellieThe study focused on understanding SARS-CoV-2 vaccine hesitancy among pregnant women in Soweto, South Africa. Pregnant women are at a greater risk of experiencing COVID-19 complications during pregnancy if infected with the SARS-CoV-2 virus. Vaccination uptake remains low in the population at large. This is a qualitative exploratory study approach using key-informant interviews. A total of sixteen key informant interviews with vaccinated pregnant women, unvaccinated pregnant women, healthcare workers and alternative healers were conducted. This study took place in Soweto townships, South Africa. Thematic qualitative analysis was used to construct themes in NVivo, where the gathered data was reviewed and analysed. The study found that pregnant women experience barriers and motivations that determine their decision to get vaccinated against COVID-19. Motivators to vaccinate health concerns, monetary benefit and structural motivators such as employment, travelling and education. Barriers included vaccine related fears were the main reason for poor vaccine uptake. The lack of knowledge, healthcare system barriers, misinformation, and lack of trust in the government were some reasons for vaccine hesitancy. The study's findings show that pregnant women's decisions to get vaccinated are significantly influenced by several barriers, perceptions and the motivators they haveItem Off-label evaluation of alternative specimen types: Cobas® plasma separation card for HIV viral load and dried blood spots for COVID-19 serology testing(2024) Mampa, Thabiso MmammitsiPlasma is the preferred specimen for HIV viral load (VL) monitoring and COVID-19 serology testing but poses a challenge in resource-limited settings due to the need for venous blood, skilled phlebotomy, and cold storage for specimen integrity. In this study dried blood spots and novel plasma separation devices (PSC, HSSE, and VLPlasma) versus plasma were investigated as alternative specimen types. The plasma separation devices (PSD) were compared to DBS to determine if eliminating cellassociated nucleic acids could improve HIV VL performance. Paired PSD (n=72), DBS (n=72) and plasma (n=72) were prepared from HIV positive residual whole blood. Similarly, paired PSC, DBS (n=91) and plasma (n=91) were prepared from HIV positive prospective whole blood to assess PSC as an alternative specimen for use on the Abbott m2000. The eluates were processed on the GeneXpert (residual blood), Abbott m2000 (residual and prospective blood) and Roche cobas® 68/8800 (prospective blood). Using plasma as reference, residual blood: DBS outperformed PSC, HSSE and VLPlasma in terms of accuracy 91.8%, compared to 87.8%, 79.1% and 75%. Prospective blood: PSC had improved performance over DBS in terms of sensitivity (92.2% and 87.1%), specificity (65% and 61.9%), and accuracy (86.9% and 80.7%). Additionally, the performance of DBS was evaluated for COVID-19 serology testing in 45 PCR-confirmed, COVID-19 positive individuals by preparing laboratory paired DBS-plasma samples. DBS were eluted using two diluents followed by manual ELISA and results compared to reference plasma testing. DBS-PBS and DBS-manufacturer’s diluent showed the same accuracy (93.6%). Kappa values (0.817 and 0.845) and sensitivity (100% and 91.4%) were similar, but DBS-PBS showed low specificity (75%) compared to DBS-diluent (100%). Off-Label use of the cobas® PSC for HIV VL and DBS for COVID-19 serology testing provides expanded options for testing in resource-limited settings. Further evaluation on capillary blood and automated laboratory workflow optimisation would still be required prior to scaled implementation.Item Understanding barriers and motivators of Covid-19 vaccine uptake among young people in Soweto, South Africa(2024) Nkhata, BernadetteThe SARS-CoV-2 novel human coronavirus is the cause of coronavirus disease (Covid-19) Covid19 is coupled with common symptoms such as fever or chills, dry cough, and tiredness. Less common symptoms include muscle or body aches, the new loss of taste or loss of infection. Vaccines are the most effective public health intervention that could protect individuals and the community from the severity of Covid-19. Several vaccine candidates have shown good safety and efficacy during recent randomized clinical trials, and seven of which have been rolled out to different African counties with over 1 million doses administered. In south Africa there has been a low uptake of the Covid-19 vaccine particularly among the youth, despite studies showing positive attitudes towards vaccination. The youth play an important role in the pandemic as they are a crucial source for the spread of the virus to more vulnerable populations. Understanding the barriers and motivations towards vaccine uptake in this population group will assist in implementing interventions targeted specifically for the youth. Aim The aim of this study is to understand the barriers and motivations towards vaccine uptake among the youth aged 18-35 in Soweto, South Africa. Methodology This is a qualitative exploratory study approach employing focus group discussions. Eight focus group discussions with both male and female participants between the ages of 18 and 35 took place in two study sites, Themb’Elihle and Meadowlands South Africa. A total of 62 participants were enrolled in the study. The Health Belief Model theoretical framework served as a guide for this investigation. Themes were developed through thematic qualitative analysis and the data collected was examined and interpreted with the use of qualitative software ATLAS.ti. Results The study found that young adults do experience barriers and motivations that determine their decision to get vaccinated against Covid-19 or not. Misinformation was among the strongest barriers to vaccination. The spread of rumors and conspiracies of the vaccines left participants feeling scared to be vaccinated. This led to the lack of trust in health care professionals, and the lack of trust in governmental authorities leading the vaccines rollout. Motivation to vaccinate came as a result of the need to protect themselves and loved ones. Participants were also willing to vaccinate as a means to reintegrate back into society and to access basic means that were previously restricted due to the Covid-19 pandemic. Conclusion The results of this study demonstrate that motivations and barriers that young adults in Soweto, South Africa encounter have a significant impact on their decision to get immunized. Policymakers are encouraged to look into the challenges faced by this group, with a focus on how social media can be used as a useful tool for reaching out to young adults and spreading correct information.