The SARS-CoV-2 pandemic: remaining uncertainties in our understanding of the epidemiology and transmission dynamics of the virus, and challenges to be overcome

Author:

Anderson Roy M.1ORCID,Vegvari Carolin1ORCID,Hollingsworth T. Déirdre23ORCID,Pi Li23ORCID,Maddren Rosie1ORCID,Ng Chi Wai1ORCID,Baggaley Rebecca F.4ORCID

Affiliation:

1. Department of Infectious Disease Epidemiology, Imperial College London, London, UK

2. Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK

3. Joint Universities Pandemic and Epidemiological Research (JUNIPER) consortium, University of Leicester, Leicester, UK

4. Department of Respiratory Sciences, University of Leicester, Leicester, UK

Abstract

Great progress has been made over the past 18 months in scientific understanding of the biology, epidemiology and pathogenesis of SARS-CoV-2. Extraordinary advances have been made in vaccine development and the execution of clinical trials of possible therapies. However, uncertainties remain, and this review assesses these in the context of virus transmission, epidemiology, control by social distancing measures and mass vaccination and the effect on all of these on emerging variants. We briefly review the current state of the global pandemic, focussing on what is, and what is not, well understood about the parameters that control viral transmission and make up the constituent parts of the basic reproductive number R 0 . Major areas of uncertainty include factors predisposing to asymptomatic infection, the population fraction that is asymptomatic, the infectiousness of asymptomatic compared to symptomatic individuals, the contribution of viral transmission of such individuals and what variables influence this. The duration of immunity post infection and post vaccination is also currently unknown, as is the phenotypic consequences of continual viral evolution and the emergence of many viral variants not just in one location, but globally, given the high connectivity between populations in the modern world. The pattern of spread of new variants is also examined. We review what can be learnt from contact tracing, household studies and whole-genome sequencing, regarding where people acquire infection, and how households are seeded with infection since they constitute a major location for viral transmission. We conclude by discussing the challenges to attaining herd immunity, given the uncertainty in the duration of vaccine-mediated immunity, the threat of continued evolution of the virus as demonstrated by the emergence and rapid spread of the Delta variant, and the logistics of vaccine manufacturing and delivery to achieve universal coverage worldwide. Significantly more support from higher income countries (HIC) is required in low- and middle-income countries over the coming year to ensure the creation of community-wide protection by mass vaccination is a global target, not one just for HIC. Unvaccinated populations create opportunities for viral evolution since the net rate of evolution is directly proportional to the number of cases occurring per unit of time. The unit for assessing success in achieving herd immunity is not any individual country, but the world.

Funder

Wellcome Trust

Li Ka Shing Foundation

Publisher

The Royal Society

Subject

Biomedical Engineering,Biomaterials,Biochemistry,Bioengineering,Biophysics,Biotechnology

Reference169 articles.

1. 1918 influenza: the mother of all pandemics. Emerging infectious Diseases;Taubenberger JK;Cent. Dis. Control Prev.,2006

2. An interactive web-based dashboard to track COVID-19 in real time

3. United Nations Joint Programme on HIV/AIDS (UNAIDS). 2020 Global HIV & AIDS statistics: 2021 fact sheet. See https://www.unaids.org/sites/default/files/media_asset/UNAIDS_FactSheet_en.pdf (accessed 22 September 2021).

4. Epidemiology, transmission dynamics and control of SARS: the 2002–2003 epidemic

5. Heterogeneities in the case fatality ratio in the West African Ebola outbreak 2013–2016

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