COVID-19 revisited: evolving insights and perspectives across the care continuum
The global pandemic of coronavirus disease 2019 (COVID-19) challenged the healthcare system worldwide in multiple ways and reshaped priorities in clinical practice, public health, and scientific inquiry. This special series of Annals of Palliative Medicine brings together diverse perspectives that reflect the evolving understanding of COVID-19’s impact across the continuum of care.
A critical dimension of pandemic response involves understanding patient-level risk factors. Pre-existing respiratory conditions including sleep apnea, chronic obstructive pulmonary disease (COPD), and interstitial lung disease have been consistently associated with heightened vulnerability to severe COVID19 outcomes (1). The first article, “Respiratory disorders and their association with clinical outcomes in COVID-19: a narrative review of current literature”, examines the critical link between pre-existing respiratory conditions and COVID-19 morbidity and mortality (2). This review synthesizes emerging data and identifies knowledge gaps, emphasizing the importance of respiratory health in risk stratification and treatment planning. The distinction between respiratory conditions such as COPD, ILD and OSA which are associated with higher burden of COVID-19 related mortality and morbidity and well – controlled asthma which did not have any such association, can help clinicians to prioritize high-risk patients for early therapeutic interventions, especially in times of limited resources. Additionally, as many of the long COVID symptoms are respiratory in nature, understanding of the pulmonary pathophysiology of COVID-19 can also pave way for advances in pulmonary rehabilitation to address long-term effects of viral pneumonia (3).
Beyond respiratory comorbidities, nutritional status emerged as a potential modifiable factor influencing COVID19 outcomes (4,5). Vitamin D deficiency has been linked to impaired immune function and increased susceptibility to respiratory infections. The second article, “Do vitamin D levels or supplementation play a role in COVID-19 outcomes?” explores the debated connection between vitamin D status and disease severity (6). By evaluating evidence from a range of studies, this narrative review considers the clinical relevance of screening and supplementation strategies during respiratory infections like COVID-19 (6). The insight into the link between vitamin D levels and clinical outcomes in COVID-19 can also applied to research on other respiratory viruses such as influenza and RSV (7).
Operational innovations also played a pivotal role in sustaining care delivery during surges. Geographic cohorting, organizing care teams by physical location, emerged as a strategy to enhance efficiency, streamline communication, and reduce cross-infection risk (8). The article, “Geographic cohorting by clinical care team: a narrative review”, shifts the focus on health system delivery innovations prompted by the pandemic (9). This review provides a comprehensive overview of geographic cohorting and its potential to improve efficiency, reduce infection risk, and enhance patient-centered care (9).
Finally, as the need for rehabilitation following COVID-19 illness was being explored (10), the pandemic also highlighted the indispensable role of rehabilitation within palliative care. The integration of rehabilitation principles into the care of those with terminal illnesses was highlighted not merely as an “extra” service but an essential component of high-quality care (11). Patients with serious illness experienced compounded challenges due to infection risk, functional decline, and psychosocial distress. The article, “Role of rehabilitation in palliative care after the COVID-19 pandemic,” reflects on the role of interdisciplinary rehabilitation services in supporting patients with serious illness during and after the crisis (12). The authors identified the need for early rehabilitation, interdisciplinary care, cardiopulmonary rehabilitation, telerehabilitation and the need for clinical practice guidelines for serious COVID-19 illness and long COVID. This article also underscores the synergy between rehabilitation and palliative care in promoting function, dignity, and quality of life in post-acute and long-term care settings, while discussing how the pandemic accelerated this integration (12).
Together, these contributions offer an insightful cross-section of the scientific and clinical lessons learned from the pandemic, while pointing to future opportunities for innovation, clinical adaptability, operational redesign, and care integration. The insights gained from the work on COVID-19 not only advance scientific knowledge for the past pandemic healthcare but also provide information to prepare more effectively for any future disruptions that might occur. Collectively, the research on COVID-19 underscores the importance of multidisciplinary research and practice that bridges the gaps in healthcare system and prioritizes efficient resource allocation along with efficient care continuity to strengthen the healthcare system for any future challenges.
Acknowledgments
None.
Footnote
Provenance and Peer Review: This article was commissioned by the editorial office, Annals of Palliative Medicine for the series “Latest Research on COVID-19”. The article did not undergo external peer review.
Funding: None.
Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://apm.amegroups.com/article/view/10.21037/apm-2026-1-0011/coif). The series “Latest Research on COVID-19” was commissioned by the editorial office without any funding or sponsorship. S.K. served as an unpaid Guest Editor for the series. P.L. served as an unpaid Guest Editor of the series and serves as an unpaid Associate Editor-in-Chief of Annals of Palliative Medicine from December 2024 to December 2026. The authors have no other conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
References
- Lohia P, Sreeram K, Nguyen P, et al. Preexisting respiratory diseases and clinical outcomes in COVID-19: a multihospital cohort study on predominantly African American population. Respir Res 2021;22:37. [Crossref] [PubMed]
- Venkat DG, Badr MS. Respiratory disorders and their association with clinical outcomes in COVID-19: a narrative review of current literature. Ann Palliat Med 2023;12:1232-43. [Crossref] [PubMed]
- Chermahini SH. Pulmonary Rehabilitation in the Post-COVID-19 Era: A Comprehensive Review. J Fam Med Health Care 2025;11:53-7. [Crossref]
- Lohia P, Nguyen P, Patel N, et al. Exploring the link between vitamin D and clinical outcomes in COVID-19. Am J Physiol Endocrinol Metab 2021;320:E520-6. [Crossref] [PubMed]
- Lohia P, Kapur S, Patel P, et al. Letter to the editor: Vitamin D levels in acute illness and clinical severity in COVID-19 patients. Respir Res 2021;22:102.
- Shetty AJ, Banerjee M, Prasad TN, et al. Do vitamin D levels or supplementation play A role in COVID-19 outcomes?-a narrative review. Ann Palliat Med 2024;13:162-77. [Crossref] [PubMed]
- Martineau AR, Forouhi NG. Vitamin D for COVID-19: a case to answer? Lancet Diabetes Endocrinol 2020;8:735-6. [Crossref] [PubMed]
- Jolly Graham A, Platt A, Knutsen K, et al. Impact of geographical cohorting, multidisciplinary rounding and incremental case management support on hospital length of stay and readmission rates: a propensity weighted analysis. BMJ Open Qual 2024;13:e002737. [Crossref] [PubMed]
- Bressman E, Kohn R, Song H, et al. Geographic cohorting by clinical care team: a narrative review. Ann Palliat Med 2023;12:855-62. [Crossref] [PubMed]
- Kapur S, Cantor Z, Bishop P, et al. Need for inpatient rehabilitation and skilled nursing services in COVID-19 patients post hospitalization: a retrospective cohort study. Ann Palliat Med 2023;12:90-102. [Crossref] [PubMed]
- Montagnini M, Wilson CM. Editorial: Rehabilitation within the context of palliative care. Front Rehabil Sci 2024;5:1490057. [Crossref] [PubMed]
- Wilson CM, Boright LE, Henshaw AM, et al. Role of rehabilitation in palliative care after the COVID-19 pandemic: a narrative review. Ann Palliat Med 2025;14:379-92. [Crossref] [PubMed]
