Significance of PPD Test for the Relationship Between BCG Vaccine and COVID-19 in Patients on Kidney Transplant Waiting List

The aim of this study was to determine the relationship between purified protein derivative of tuberculin (PPD) values, an indicator of BCG protection, and COVID-19 disease in patients with end-stage renal disease (ESRD) on the kidney transplant waiting list.Age, sex, dialysis type, ERSD etiologies, and PPD values of patients on the renal transplant waiting list were recorded. SARS-CoV-2 PCR data, whether the patients were previously infected with the virus, and, if infected, the severity of the disease were noted. Data were statistically compared.PCR of 87 (47.02%) of 185 patients were studied; 107 of the patients were male and 78 were female, with a mean age of 52.8 years. The test result was positive for 28 patients. Of the patients for whom PCR was studied, 41 had a negative PPD result, while 46 had a positive PPD result. There was no correlation with SARS-CoV-2 PCR positivity in patients with a PPD ≤ 5 mm and > 5 mm. However, patients with pneumonic infiltration who required hospitalization had a significantly higher PPD value.The PPD measurement, which is an indicator of BCG protection, might be a significant parameter for predicting the course of the disease in SARS-CoV-2 pneumonia.