**Preface to "The Digital Health in the Pandemic Era"**

Digital health, virtual assistance, and telemedicine are terms often used interchangeably to refer to remote medical assistance, monitoring, and care. Several studies and insights have developed these issues, analyzing the advantages and disadvantages and successes and failures and offering reflections on the implications and issues surrounding these technologies in the health domain. The results of these investigations are affecting the redesign of hospital and outpatient management based on digital innovation using eHealth and mHealth. Digital health encompasses a broad spectrum of technologies, including wearable personal devices and internal devices, as well as various types of sensors and innovative solutions. Digital health can help identify risks and correct assistance in the diagnosis, treatment, and monitoring of health conditions, offering new potential both to the population and insiders in the health domain. During the COVID-19 pandemic, this approach made it possible to offer assistance and continue care at home, protecting patients, preserving health workers, limiting the spread of the virus, and reducing the need for hospitalization. For example, the opportunity to make digital measurements of oxygen saturation at home has been used to make fundamental decisions regarding the health of patients, such as the choice between hospitalization and respiratory support. It has also become possible to monitor frail patients from home (e.g., with diabetes or cardiovascular or oncological problems), improving the continuity of care and reducing the pressure on hospitals. Digital Health (DH) also contributed to the fight against the pandemic in various new ways, such as in the management of digital contact tracing and vaccination processes through smart technology. This reprint, which deals with the development of DH during the COVID-19 pandemic, contains contributions from various experts in different fields.

Emerging topics in the Special Issue were:

·Digital contact tracing (DCT) and its impact on the spread of the pandemic in different populations, together with the factors that influenced its use.

·The use of DH in life sciences, including anatomy, bioinformatics, cell biology, neuroscience, physiology, and population biology, among others.

·Artificial intelligence (AI) applications in DH, including COVID-19-specific diagnostics, physical activity monitoring, obesity diagnosis, the detection of abnormalities in chest X-rays, and mental health monitoring.

·Large-scale population surveys analyzing the impact of biomedical parameters, health determinants, and digital literacy on the population.

·Remote healthcare interventions and their impact on self-care in chronic patients.

·Chatbots in the health domain and their increasing use during the pandemic.

My sincere thanks to Shane Zheng, who provided exceptional support in every phase of the creation of this collection.

> **Daniele Giansanti** *Editor*
