Russia's invasion of Ukraine (February 24, 2022) has begun and there are concerns about the impact on health care supply and mental health. This study analyzed tweets in the Ukrainian language to capture the medical needs and mental health conditions in wartime Ukraine by focusing on ostensibly relevant words. The number of tweets containing the keywords and their overall proportion was compared before and after the Russian invasion of Ukraine. The survey period was divided into four phasesthe pre-2022 Russian invasion, acute phase (4 weeks), subacute phase (12 weeks), and the chronic phase (8 weeks) up to August 10, 2022. The analysis targeted tweets sent in Ukrainian. The tweets were screened using a set of six classes with 75 key groups and 303 Ukrainian (204 original Japanese) keywords. Overall, 98,526,440 tweets were analyzed, with a pre-invasion and post-onset average of 1,096,976 and 3,328,243 tweets/week (a 3.0-fold increase), respectively. Of these, 3,197,443 tweets contained the keywords, with a pre-invasion and invasion average of 26,241 and 114,640 tweets/week (a 4.4-fold increase), respectively. The post-onset phase witnessed a considerable increase in all classes-medical services, treatment, medical resources, medical situations, and special situations-but not in the symptom class. Keywords related to psychological distress and anxiety immediately increased during the acute phase; those related to depression and post-traumatic stress reactions continued increasing as the invasion persisted, which may have reflected the mental state of those impacted. Analyzing tweets is useful for predicting people's real-time physical and mental health needs during wartime. Keywords: Social Network System; Twitter; physical and mental health needs; human-induced hazards; Ukraine operation." On the same day, military operations began throughout Ukraine, including in 3 the vicinity of the Ukrainian capital, Kiev (Russian Ministry of Foreign Affairs 2022). 4 The two countries have been engaged in a series of confrontations and conflicts, 5 beginning in the Donbass region of southeastern Ukraine, including the annexation of the 6 Crimean Peninsula in 2014; as of the end of October 2022, military operations are still 7 ongoing. This military conflict has predominantly been fought inside Ukraine. Ukrainian 8 citizens are exposed to daily threats to their lives, including shelling (Adams et al. 2022). 9 A human-induced hazard is similar to sudden-onset natural hazards; the 2022 Russian invasion clearly created a different environment-a disaster. Concerns exist regarding the impact on the medical supply and mental health, and the sustainability of daily life (Patel and Erickson 2022; Awuah et al. 2022).Life-threatening events-natural hazards, wars, accidents, crimes, and abusetrigger acute stress reactions that precipitate the development of post-traumatic stress disorder (PTSD). Numerous mental health surveys and research projects have examined past disasters caused by natural hazards and chemical, biological, radiologica...

Disaster response procedures have been developed and improved following the Great East Japan Earthquake. Innovative services have also been created through digital transformation, including an acceleration and deepening of artificial intelligence technology. Things that were once technically impossible are now possible. These innovative technologies will spread across various fields, and disaster response will not be an exception. The Ministry of Health, Labour and Welfare is promoting the use of personal health records in a way that effectively supports the management of treatments by using data from wearable devices and specific applications. During the COVID-19 pandemic, the trade-off between protecting personal information and enabling social benefits, such as in the use of digital tracking, and infodemics, including misinformation, have become new social challenges. Reviewing past disaster preparedness and the services and value provided by digital transformation indicates what new disaster preparedness should be. Digital transformation does not require literacy (ability to collect, analyze, and use information) but competence (beneficial behavioral traits derived from experience). Understanding behavior through data and enabling rational behavior are crucial. By increasing human productivity, we can save time and improve self-and mutual-help in times of disaster. Medical information and digital services must be properly used in normal times. A society that uses such services will be more disaster resilient.