Cari van Schalkwyk, PhD

Researcher in Statistics

Research theme: Combatting Infections of National Priority

Cari van Schalkwyk studied Mathematical Statistics at the University of Stellenbosch and started her relationship with SACEMA in 2007 through her Masters project on estimating mean duration of recent HIV infection. She started working at SACEMA as a Statistician in November 2010 and has been involved in projects related to HIV, TB, COVID, HPV and cervical cancer. Her PhD work (with Dr Leigh Johnson at the University of Cape Town) focused on HIV and HPV transmission dynamics, the natural history of HPV and the impact of different vaccination and screening strategies on cervical cancer incidence in South Africa.

Recent publications

Pulliam JCR, van Schalkwyk C, Govender N, von Gottberg A, Cohen C, Groom M, Dushoff J, Mlisana K, Moultrie H (2021) SARS-CoV-2 reinfection trends in South Africa: analysis of routine surveillance data doi.org/10.1101/2021.11.11.21266068

van Schalkwyk C, Moodley Jennifer, Welte A, Johnson LF (2021) Modelling the impact of prevention strategies on cervical cancer incidence in South Africa doi/abs/10.1002/ijc.33716

Osman M, C van Schalkwyk, P, Naidoo, et al (2021) Mortality during tuberculosis treatment in South Africa using an 8-year analysis of the national tuberculosis treatment register Scientific Reports 11(1):15894 https://doi.org/10.1038/s41598-021-95331-w

Van Schalkwyk C., J. Moodley, A. Welte, LF. Johnson (2021) Modelling the impact of prevention strategies on cervical cancer incidence in South Africa International Journal of Cancer 149:8 https://doi.org/10.1002/ijc.33716

Louw C, van Schalkwyk EJ, Conradie R, Louw R, Engelbrecht Y, Storbeck K, Swart AC, van Niekerk DD, Snoep JL, Swart P (2021) Computational modelling of the 4 and 5 adrenal steroidogenic pathways provides insight into hypocortisolism doi.org/10.1016/j.mce.2021.111194

van Schalkwyk C, Dorrington RE, Seatlhodi T, Velasquez C, Feizzadeh A, Johnson LF (2021) Modelling of HIV prevention and treatment progress in five South African metropolitan districts doi.org/10.1038/s41598-021-85154-0

Pearson, C. A. B., C. van Schalkwyk , A.M. Foss , K.M. O'Reilly, SACEMA's Modelling and Analysis Response Team, CMMID COVID-19 Working Group, and J.R.C. Pulliam (2020) Projected early spread of COVID-19 in Africa through 1 June 2020. Eurosurveillance 25(18) 2000543 doi: 10.2807/1560-7917.ES.2020.25.18.2000543

Mehta, U.C., C. van Schalkwyk, P. Naidoo, A. Ramkissoon, O. Mhlongo, N.R. Maharaj, N. Naidoo, K. Fieggen, M.F. Urban, S. Krog, A. Welte, M. Dheda, Y. Pillay, & N.F. Moran (2019) Birth outcomes following antiretroviral exposure during pregnancy: Initial results from a pregnancy exposure registry in South Africa Southern African Journal of HIV Medicine 20(1):12 doi:10.4102/sajhivmed.v20i1.971

Gonese, E., P.H. Kilmarx, C. van Schalkwyk, E. Grebe, K. Mutasa, R. Ntozini, B. Parekh, T. Dobbs, Y.D. Pottinger, S. Masciotra, M. Owen, J.B. Nachega, G. van Zyl, & J.W. Hargrove (2019) Evaluation of the Performance of Three Biomarker Assays for Recent HIV Infection Using a Well-Characterized HIV-1 Subtype C Incidence Cohort. AIDS Research and Human Retroviruses 35(7):615-627 doi: 10.1089/aid.2019.0033

Van Schalkwyk, C., J. Moodley, A. Welte, & L.F. Johnson (2019) Estimated impact of human papillomavirus vaccines on infection burden: The effect of structural assumptions. Vaccine 37 (36): 5460-5465 doi: 10.1016/j.vaccine.2019.06.013

Van Schalkwyk, C., J. Maritz, G.U. Van Zyl, W. Preiser, & A. Welte (2019) Pooled PCR testing of dried blood spots for infant HIV diagnosis is cost efficient and accurate. BMC Infectious Diseases 19:136 doi: 10.1186/s12879-019-3767-z

Hargrove, J.W., S English, S.J. Torr, J. Lord, R.L Haines, C. van Schalkwyk, J. Patterson, & G.Vale (2019) Wing length and host location in tsetse (Glossina spp.): implications for control using stationary baits Parasites & Vectors 12(1):24. doi: 10.1186/s13071-018-3274-x.

Van Schalkwyk, C., J. Moodley, A. Welte, & L.F. Johnson (2018) Are associations between HIV and human papillomavirus transmission due to behavioural confounding or biological effects? Sexualy Transmitted Infections 95(2):122-128. doi: 10.1136/sextrans-2018-053558

Van Schalkwyk, C., & M.M. Claassens. (2018) Estimating the magnitude of pulmonary tuberculosis patients missed by primary health care clinics in South Africa. International Journal of Tuberculosis and Lung Disease 22(3):264-272. doi: 10.5588/ijtld.17.0491

Mbulawa, Z.Z.A., C. Van Schalkwyk, N. Hu, T.L. Meiring, S. Barnabas, S. Dabee, H.B. Jaspan, J. Kriek, S.Z. Jaumdally, E. Muller, L. Bekker, D.A. Lewis, J. Dietrich, G. Gray, J.S. Passmore, & A. Williamson. (2018) High human papillomavirus (HPV) prevalence in South African adolescents and young women encourages expanded HPV vaccination campaigns. PLOS ONE 13(1):e0190166:15. doi: 10.1371/journal.pone.0190166

Norris, S.A., A. Daar, D. Balasubramanian, P. Byass, E. Kimani-Murage, A. Macnab, C. Pauw, A. Singhal, C. Yajnik, J. Akazili, N. Levitt, J. Maatoug, N. Mkhwanazi, S.E. Moore, M. Nyirenda, J.R.C. Pulliam, T. Rochat, R. Said-Mohamed, S. Seedat, E. Sobngwi, M. Tomlinson, E. Toska & C. van Schalkwyk (2017) Understanding and acting on the developmental origins of health and disease in Africa would improve health across generations. Global Health Action 10(1):1334985. doi: 10(1): 1334985.

Hargrove, J.W., C. van Schalkwyk, J.H. Humphrey, K. Mutasa, R. Ntozini, S.M. Owen, S. Masciotra, B.S. Parekh, Y.T. Duong, T. Dobbs, P.H. Kilmarx, & E. Gonese. (2017) Heightened HIV antibody responses in postpartum women as exemplified by recent infection assays: implications for incidence estimates. AIDS Research and Human Retroviruses 33(9). doi: 10.1089/aid.2016.0319

Claassens, M.M., C. van Schalkwyk, S. Floyd, H. Ayles & N. Beyers (2017) Symptom screening rules to identify active pulmonary tuberculosis: Findings from the Zambian South African Tuberculosis and HIV/AIDS Reduction (ZAMSTAR) trial prevalence surveys. PLOS ONE 12(3): e0172881. doi: 10.1371/journal.pone.0172881

Sattar S, Van Schalkwyk C, Claassens M, Dunbar R, Floyd S, Enarson D. A, Godfrey-Faussett P, Ayles H, Beyers N. (2014) Symptom reporting among prevalent tuberculosis cases who smoke, are HIV-positive or have hyperglycaemia. Public Health Action 4(4). doi: 10.5588/pha.14.0081.

Du Toit E, van Schalkwyk C, Dunbar R, Jennings K, Yang B, Coetzee D, Beyers N. (2014) Missed opportunities for retention in pre-ART care in Cape Town, South Africa. PLoS One. 9(5). doi: 10.1371/journal.pone.0096867.

Van Schalkwyk C, Variava E, Shapiro A. E, Rakgokong M, Masonoke K, Lebina L, Welte A, Martinson N. (2014) Incidence of TB and HIV in prospectively followed household contacts of TB index patients in South Africa. PLoS One. 9(4). doi: 10.1371/journal.pone.0095372.

Mareli M. Claassens, Cari van Schalkwyk, Elizabeth du Toit, Eline Roest, Carl J. Lombard, Donald A. Enarson, Nulda Beyers, and Martien W. Borgdorff. (2013) Tuberculosis in Healthcare Workers and Infection Control Measures at Primary Healthcare Facilities in South Africa. PLoS One 8(10). doi: 10.1371/journal.pone.0076272.

van Schalkwyk C, Mndzebele S, Hlophe T, Garcia Calleja J. M, Korenromp E. L, Stoneburner R, Pervilhac C. (2013) Outcomes and impact of HIV prevention, ART and TB programs in Swaziland--early evidence from public health triangulation. PLoS One. 8(7). doi: 10.1371/journal.pone.0069437.

Claassens M, van Schalkwyk C, den Haan L, Floyd S, Dunbar R, van Helden P, Godfrey-Faussett P, Ayles H, Borgdorff M, Enarson D, Beyers N. (2013) High prevalence of tuberculosis and insufficient case detection in two communities in the Western Cape, South Africa. PLoS One 8(4). doi: 10.1371/journal.pone.0058689.

Hargrove J, Eastwood H, Mahiane G, van Schalkwyk C. (2012) How should we best estimate the mean recency duration for the BED method? PLoS One 7(11). doi: 10.1371/journal.pone.0049661.

Cari van Schalkwyk, Madeleine Cule, Alex Welte, Paul van Helden, Gian van der Spuy, and Pieter Uys. (2012) Towards Eliminating Bias in Cluster Analysis of TB Genotyped Data. PLoS One 7(3). doi: 10.1371/journal.pone.0034109.

Hargrove J., C. van Schalkwyk & H. Eastwood (2012) BED Estimates of HIV Incidence: Resolving the Differences, Making Things Simpler. PLoS One. 7(1): e29736. doi:10.1371/journal.pone.0029736.

DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis