Cheryl Baxter

Dr. Cheryl Baxter

orcid

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 June 2022 in Nature Medicine
Verified
Journal Article
Open access
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HTHouriiyah Tegally
Houriiyah Tegally
MMMonika Moir
Monika Moir
JEJosie Everatt
Josie Everatt
Marta GiovanettiMarta Giovanetti
Marta Giovanetti
CSCathrine Scheepers
Cathrine Scheepers
TOTulio De Oliveira
Tulio De Oliveira
Three lineages (BA.1, BA.2 and BA.3) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant of concern predominantly drove South Africa’s fourth Coronavirus Disease 2019 (COVID-19) wave. We have now identified two new lineages, BA.4 and BA.5, responsible for a fifth wave of infections. The spike proteins of BA.4 and BA.5 are identical, and similar to BA.2 except for the addition of 69–70 deletion (present in the Alpha variant and the BA.1 lineage), L452R (present in the Delta variant), F486V and the wild-type amino acid at Q493. The two lineages differ only outside of the spike region. The 69–70 deletion in spike allows these lineages to be identified by the proxy marker of S-gene target failure, on the background of variants not possessing this feature. BA.4 and BA.5 have rapidly replaced BA.2, reaching more than 50% of sequenced cases in South Africa by the first week of April 2022. Using a multinomial logistic regression model, we estimated growth advantages for BA.4 and BA.5 of 0.08 (95% confidence interval (CI): 0.08–0.09) and 0.10 (95% CI: 0.09–0.11) per day, respectively, over BA.2 in South Africa. The continued discovery of genetically diverse Omicron lineages points to the hypothesis that a discrete reservoir, such as human chronic infections and/or animal hosts, is potentially contributing to further evolution and dispersal of the virus.

13 June 2024 in Nature Medicine
Verified
Journal Article
Open access
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EVEmmanuel Hasivirwe Vakaniaki
Emmanuel Hasivirwe Vakaniaki
CKCris Kacita
Cris Kacita
ELEddy Kinganda - Lusamaki
Eddy Kinganda - Lusamaki
ÁOÁine O’tOole
Áine O’tOole
TWTony Wawina-Bokalanga
Tony Wawina-Bokalanga
PMPlacide Kingebeni Mbala
Placide Kingebeni Mbala
Outbreaks of monkeypox (mpox) have historically resulted from zoonotic spillover of clade I monkeypox virus (MPXV) in Central Africa and clade II MPXV in West Africa. In 2022, subclade IIb caused a global epidemic linked to transmission through sexual contact. Here we describe the epidemiological and genomic features of an mpox outbreak in a mining region in eastern Democratic Republic of the Congo, caused by clade I MPXV. Surveillance data collected between September 2023 and January 2024 identified 241 suspected cases. Genomic analysis demonstrates a distinct clade I lineage divergent from previously circulating strains in the Democratic Republic of the Congo. Of the 108 polymerase chain reaction-confirmed mpox cases, the median age of individuals was 22 years, 51.9% were female and 29% were sex workers, suggesting a potential role for sexual transmission. The predominance of APOBEC3-type mutations and the estimated emergence time around mid-September 2023 imply recent sustained human-to-human transmission.

23 August 2022 in PLOS Biology
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Journal Article
Open access
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THT. Happi
T. Happi
IAIfedayo Adetifa
Ifedayo Adetifa
PMPlacide Mbala
Placide Mbala
RNRichard Njouom
Richard Njouom
ENEmmanuel Nakoune
Emmanuel Nakoune
TOTulio De Oliveira
Tulio De Oliveira
We propose a novel, non-discriminatory classification of monkeypox virus diversity. Together with the World Health Organization, we named three clades (I, IIa and IIb) in order of detection. Within IIb, the cause of the current global outbreak, we identified multiple lineages (A.1, A.2, A.1.1 and B.1) to support real-time genomic surveillance.

7 October 2022 in Science
Verified
Journal Article
Closed access
HTHouriiyah Tegally
Houriiyah Tegally
JSJames Emmanuel San
James Emmanuel San
MCMatthew Cotten
Matthew Cotten
MMMonika Moir
Monika Moir
BTBryan Tegomoh
Bryan Tegomoh
EWEduan Wilkinson
Eduan Wilkinson
Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern—particularly Alpha, Beta, Delta, and Omicron—on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century.

22 January 2022 in Current HIV/AIDS Reports
Verified
Journal Article
Open access
PDF file
QKQuarraisha Abdool Karim
Quarraisha Abdool Karim
CBCheryl Baxter
Cheryl Baxter
Purpose of Review: To describe how mitigation measures against COVID-19 have impacted HIV and TB research in South Africa. Recent Findings: South Africa has the highest number of COVID-19 (34%) cases in Africa, accounting for 43% of all reported COVID-19-related deaths on the continent. The country accounts for 20% of all people living with HIV and ranked third in the world for new TB infections in 2019. Summary: While South Africa’s investments in its HIV and TB responses enabled it to pivot rapidly to respond to the emerging COVID-19 epidemic, it negatively impacted the HIV and TB response through temporary suspension of research, diversion of key resources for HIV and TB control, and patient access to health care facilities; the full extent of this has yet to emerge. Success in integrating responses to the colliding epidemics could potentially enhance survival outcomes and ensure gains made to date in HIV and TB are not reversed and we stay on track toward achieving the UN 2030 Sustainable Development Goals.

19 November 2019 in Nature Communications
Verified
Journal Article
Open access
LLLenine Liebenberg
Lenine Liebenberg
LMLyle R. McKinnon
Lyle R. McKinnon
NYNonhlanhla Yende-Zuma
Nonhlanhla Yende-Zuma
NGNigel Garrett
Nigel Garrett
CBCheryl Baxter
Cheryl Baxter
QKQuarraisha Abdool Karim
Quarraisha Abdool Karim
Human papillomavirus (HPV) infection correlates with higher rates of HIV acquisition, but the underlying biological mechanisms are unclear. Here we study associations between HPV and HIV acquisition and relate these to vaginal cytokine profiles in an observational cohort of women at high risk of HIV infection (CAPRISA 004, n = 779) and with 74% HPV prevalence. We report here that HPV infection associates with a 2.5-fold increase in HIV acquisition risk in this population (95% CI: 1.2–5.3). Among 48 vaginal cytokines profiled, cytokines associated with HPV infection overlap substantially with cytokines associated with HIV risk, but are distinct from those observed in HPV negative women. Although our data do not establish a causative link between HPV status and the risk of HIV, we suggest that increasing HPV vaccination coverage may carry an additional benefit of reducing the risk of contracting HIV infection, particularly in regions with high HPV prevalence.