Modelling the impact of COVID-19 on HIV
Authors: Maia Lesosky, Landon Myer
Journal: The Lancet HIV (2020)

The global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the response to the pandemic by national authorities, has been unprecedented in its rapidity and scope. The virus and our responses to the epidemic have driven profound shifts in social interactions, national economies, and health services across the world. Understanding the implications of these shifts, particularly over the long term, is a massive challenge facing policy makers. In this context, mathematical models or simulations to predict epidemics and the effects of efforts to mitigate them are well established tools for planning public health programmes. These models provide broad insights into what could happen in the future under different scenarios and assumptions. In emergent epidemics, these models are especially valuable to generate forecasts relatively rapidly, and, indeed, mathematical models of SARS-CoV-2 transmission and its effects on population health have thrived in the past few months.1Adam D Special report: the simulations driving the world's response to COVID-19.Nature. 2020; 580: 316-318Crossref PubMed Scopus (264) Google Scholar However, the modelling of epidemics and their impacts is a highly uncertain business. Developing, parameterising, calibrating, and validating a model involves oversimplifications of a poorly understood reality, adaptations of imperfect empirical data, and gross assumptions to explain away the huge unknowns.2May RM Uses and abuses of mathematics in biology.Science. 2004; 303: 790-793Crossref PubMed Scopus (304) Google Scholar, 3Kretzschmar M Disease modeling for public health: added value, challenges, and institutional constraints.J Public Health Policy. 2020; 41: 39-51Crossref PubMed Scopus (24) Google Scholar Like all scientists, mathematical modellers often have a vested interest in their own tools and results, and understandings of uncertainty in the modelling process are often underdeveloped.4Barton CM Alberti M Ames D et al.Call for transparency of COVID-19 models.Science. 2020; 368: 482-483Crossref PubMed Google Scholar As a result, no single model ever provides an absolute answer; arguably, the findings of any mathematical model should be read with a healthy accompaniment of scepticism. In The Lancet HIV, the Article by Britta Jewell and colleagues5Jewell BL Mudimu E Stover J et al.Potential effects of disruption to HIV programmes in sub-Saharan Africa caused by COVID-19: results from multiple mathematical models.Lancet HIV. 2020; Aug 6; https://doi.org/10.1016/S2352-3018(20)30211-3Summary Full Text Full Text PDF Scopus (231) Google Scholar provides a refreshing approach to understanding how responses to SARS-CoV-2 might influence the course of the HIV epidemic. The analysis brings together the results of five different mathematical models, each asking the same question. The results are largely consistent across the models and arrive at a sobering conclusion: relatively short interruptions in HIV prevention and treatment services, and particularly antiretroviral therapy programmes, might lead to substantial increases in mortality. The magnitude of these increases could parallel deaths due to SARS-CoV-2 infection in countries where HIV prevalence is high. The joint presentation of multiple, independent mathematical models investigating a single question provides a strong basis for understanding the strengths and limitations of each model, and for inference towards public health policy making. This method should be viewed as a gold standard approach to presenting findings as we move away from attempting to make inferences from any single mathematical model in isolation. As this new gold standard emerges, improved standardisation and transparency in the presentation of model structure, assumptions, and results will be required. Furthermore, new methodological questions are likely to emerge, including around whether and how to combine model results using meta-analytical approaches. Jewell and colleagues begin to explore useful directions in their study, but much more work is needed. The convergence of findings across these five models provides robust insights into a concern held by many individuals at risk of or living with HIV, and clinicians and policy makers involved in HIV services.6Davey DJ Bekker L-G Coates TJ Myer L Contracting HIV or contracting SAR-CoV-2 (COVID- 19) in pregnancy? Balancing the risks and benefits.AIDS Behav. 2020; (published online April 13.)https://doi.org/10.1007/s10461-020-02861-xPubMed Google Scholar With the work of Jewell and colleagues, these concerns can shift from an anecdote that provokes anxiety to a more tangible phenomenon that policy makers can work to prevent. However, notably, this work addresses only the effect of the SARS-CoV-2 response on HIV services, and does not go into the potential effects on other health conditions and services, including other infectious diseases,7Hogan AB Jewell BL Sherrard-Smith E et al.Potential impact of the COVID-19 pandemic on HIV, tuberculosis, and malaria in low-income and middle-income countries: a modelling study.Lancet Glob Health. 2020; (published online July 13.)https://doi.org/10.1016/S2214-109X(20)30288-6Summary Full Text Full Text PDF Scopus (467) Google Scholar maternal and child health,8Roberton T Carter ED Chou VB et al.Early estimates of the indirect effects of the COVID-19 pandemic on maternal and child mortality in low-income and middle-income countries: a modelling study.Lancet Glob Health. 2020; 8: e901-e908Summary Full Text Full Text PDF PubMed Scopus (745) Google Scholar and chronic disease care.9Baral SD Mishra S Diouf D Phanuphak N Dowdy D The public health response to COVID-19: balancing precaution and unintended consequences.Ann Epidemiol. 2020; 46: 12-13Crossref PubMed Scopus (17) Google Scholar Considering these issues, we must recognise that not all health sequelae are negative and some notable health benefits might result from the response to SARS-CoV-2,10Matzopoulos R Walls H Cook S London L South Africa's COVID-19 alcohol sales ban: the potential for better policy-making.Int J Health Policy Manag. 2020; (published online June 10.)https://doi.org/10.34172/ijhpm.2020.93Crossref PubMed Scopus (33) Google Scholar linking back to the importance of mathematical modelling in weighing risks and benefits across a population. In its broadest interpretation, the study by Jewell and colleagues asks the uncomfortable question of whether the response to SARS-CoV-2 might lead to greater long-term morbidity and mortality than the virus itself. Such a possibility could have profound implications for public health policies and programmes globally. However, answering this uncomfortable question will require much more than mathematical modelling and will no doubt drive empirical investigations for years to come. We declare no competing interests. Potential effects of disruption to HIV programmes in sub-Saharan Africa caused by COVID-19: results from multiple mathematical modelsDuring the COVID-19 pandemic, the primary priority for governments, donors, suppliers, and communities should focus on maintaining uninterrupted supply of ART drugs for people with HIV to avoid additional HIV-related deaths. The provision of other HIV prevention measures is also important to prevent any increase in HIV incidence. 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