How coronavirus disease 2019 vaccination affect the level of vitamin D in serum and hair?

Background The world has suffered from the coronavirus disease 2019 (COVID-19) pandemic because of its high mortality and morbidity, resulting in the emergence of a variety of vaccines. Serum levels of vitamin D are inversely correlated with the incidence and severity of COVID-19. Hair loss is one of the most frequent complaints of COVID-19 patients. Objectives This study aims to evaluate the impact of COVID-19 vaccination on vitamin D levels in hair and serum. Patients and methods This study was conducted on 80 participants, divided into four equal groups according to the received COVID-19 vaccine. Serum and hair samples were obtained to measure vitamin D levels before and after 1 week of first and second dose of vaccinesand history of hair loss was recorded. Results Significant lower vitamin D levels in both serum and hair were recorded after the first dose (P<0.001). After the second dose, serum vitamin D has significantly increased in all groups (P<0.05), except the Pfizer group (P=0.07). Meanwhile, hair vitamin D had a nonsignificant increase in all groups (P>0.05). Hair loss was a frequent complaint after the COVID-19 vaccination, especially with the AstraZeneca vaccine, and less noted with the Pfizer vaccine. Conclusion COVID-19 vaccines harm serum and hair vitamin D with the potential increase in hair loss.