Aims: The world is in the grip of the COVID-19 pandemic. Here, we report two infant cases of vitamin D (VD) deficiency associated with a lack of sunlight. Presentations of case: Patients and their families stayed indoors according to orders issued by the public administration. Conclusion: Physicians should be aware that many health problems are associated with long stays at home, including VD deficiency, which may be associated with a lack of sunlight.