COVID-19 and thyroid disease: an infodemiological pilot study

Abstract Introduction: Some studies have linked COVID-19 with thyroid disease. Google Trends (GT) searches may reflect disease epidemiology. Recently, GT searches for COVID-19-associated terms have been linked to the epidemiology of COVID-19. In this study we aimed to assess COVID-19 cases per se vs COVID-19-associated GT searches and thyroid-associated GT searches. Materials-Methods: We collected data on worldwide weekly GT searches regarding “COVID-19”, “SARS-COV-2”, “coronavirus”, “smell”, “taste”, “fatigue”, “cough”, “thyroid”, “thyroiditis” and “subacute thyroiditis” for 92 weeks and worldwide weekly COVID-19 cases' statistics in the same time period. The study period was split in half and in each time period we performed cross-correlation analysis and mediation analysis. Results Significant positive CCF values were noted in both time periods; while COVID-19 cases per se were associated with “thyroid” searches in both time periods, significant CCFs for “fatigue”, “COVID-19” and “SARS-COV-s” were mostly found in the second time period. In the latter period, the effect of “COVID-19” searches on “thyroid” searches was significantly mediated by COVID-19 cases (p=0.048). Discussion COVID-19 cases per se were found to be associated with no lag with GT searches for COVID-19 symptoms in the first time period and in the second time period to lead searches for symptoms, COVID-19 terms as well as thyroid terms. Searches for a non-specific symptom or COVID-19 search terms mostly lead GT “thyroid” searches, in the second time period. This time frame/sequence particularly in the second time period (noted by the preponderance of the SARS-COV-2 delta variant), lends some credence to associations of COVID-19 cases per se with (apparent) thyroid disease (via searches for them).