Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Dose, Infection, and Disease Outcomes for Coronavirus Disease 2019 (COVID-19): A Review.

The relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dose, infection, and coronavirus disease 2019 (COVID-19) outcomes remains poorly understood. This review summarizes the existing literature regarding this issue, identifies gaps in current knowledge, and suggests opportunities for future research. In humans, host characteristics, including age, sex, comorbidities, smoking, and pregnancy, are associated with severe COVID-19. Similarly, in animals, host factors are strong determinants of disease severity, although most animal infection models manifest clinically with mild to moderate respiratory disease. The influence of variants of concern as it relates to infectious dose, consequence of overall pathogenicity, and disease outcome in dose-response remains unknown. Epidemiologic data suggest a dose-response relationship for infection contrasting with limited and inconsistent surrogate-based evidence between dose and disease severity. Recommendations include the design of future infection studies in animal models to investigate inoculating dose on outcomes and the use of better proxies for dose in human epidemiology studies.

Revisiting COVID-19 policies: 10 evidence-based recommendations for where to go from here.

BACKGROUND: Strategies to control coronavirus 2019 disease (COVID-19) have often been based on preliminary and limited data and have tended to be slow to evolve as new evidence emerges. Yet knowledge about COVID-19 has grown exponentially, and the expanding rollout of vaccines presents further opportunity to reassess the response to the pandemic more broadly. MAIN TEXT: We review the latest evidence concerning 10 key COVID-19 policy and strategic areas, specifically addressing: 1) the expansion of equitable vaccine distribution, 2) the need to ease restrictions as hospitalization and mortality rates eventually fall, 3) the advantages of emphasizing educational and harm reduction approaches over coercive and punitive measures, 4) the need to encourage outdoor activities, 5) the imperative to reopen schools, 6) the far-reaching and long-term economic and psychosocial consequences of sustained lockdowns, 7) the excessive focus on surface disinfection and other ineffective measures, 8) the importance of reassessing testing policies and practices, 9) the need for increasing access to outpatient therapies and prophylactics, and 10) the necessity to better prepare for future pandemics. CONCLUSIONS: While remarkably effective vaccines have engendered great hope, some widely held assumptions underlying current policy approaches call for an evidence-based reassessment. COVID-19 will require ongoing mitigation for the foreseeable future as it transforms from a pandemic into an endemic infection, but maintaining a constant state of emergency is not viable. A more realistic public health approach is to adjust current mitigation goals to be more data-driven and to minimize unintended harms associated with unfocused or ineffective control efforts. Based on the latest evidence, we therefore present recommendations for refining 10 key policy areas, and for applying lessons learned from COVID-19 to prevent and prepare for future pandemics.

COVID-19 false dichotomies and a comprehensive review of the evidence regarding public health, COVID-19 symptomatology, SARS-CoV-2 transmission, mask wearing, and reinfection.

Scientists across disciplines, policymakers, and journalists have voiced frustration at the unprecedented polarization and misinformation around coronavirus disease 2019 (COVID-19) pandemic. Several false dichotomies have been used to polarize debates while oversimplifying complex issues. In this comprehensive narrative review, we deconstruct six common COVID-19 false dichotomies, address the evidence on these topics, identify insights relevant to effective pandemic responses, and highlight knowledge gaps and uncertainties. The topics of this review are: 1) Health and lives vs. economy and livelihoods, 2) Indefinite lockdown vs. unlimited reopening, 3) Symptomatic vs. asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, 4) Droplet vs. aerosol transmission of SARS-CoV-2, 5) Masks for all vs. no masking, and 6) SARS-CoV-2 reinfection vs. no reinfection. We discuss the importance of multidisciplinary integration (health, social, and physical sciences), multilayered approaches to reducing risk ("Emmentaler cheese model"), harm reduction, smart masking, relaxation of interventions, and context-sensitive policymaking for COVID-19 response plans. We also address the challenges in understanding the broad clinical presentation of COVID-19, SARS-CoV-2 transmission, and SARS-CoV-2 reinfection. These key issues of science and public health policy have been presented as false dichotomies during the pandemic. However, they are hardly binary, simple, or uniform, and therefore should not be framed as polar extremes. We urge a nuanced understanding of the science and caution against black-or-white messaging, all-or-nothing guidance, and one-size-fits-all approaches. There is a need for meaningful public health communication and science-informed policies that recognize shades of gray, uncertainties, local context, and social determinants of health.