Possible Roles of Low-Fat Yogurt and Cheese with in Further Side Effects of COVID-19 Vaccination: A Case-Control Study

Background and Objectives: Morbidity and mortality caused by sever acute respiratory syndrome 2 (SARS-CoV-2) can decrease with effective vaccination. The current study assessed relationships between the food intakes and nutritional habits before vaccination and the severity of vaccination-linked symptoms. Materials and Methods: Totally, 586 participants (377 cases with moderate to severe symptoms after COVID-19 vaccination and 209 controls with no clinical symptoms after vaccination) were investigated in a case-control study. Food frequency questionnaire was used to investigate dietary food group intakes during a year. Food habits were assessed using general questionnaires. Logistic regression models were used to estimate strength of the associations between the history of food intakes and the odds ratios (ORs) of side symptoms after vaccination. Results: After considering energy intake, gender, vaccine type, type of dairy products and BMI in the logistic regression models, consuming yogurt and cheese during the year before the vaccination significantly increased the occurrence of side effects after vaccination with COVID-19 vaccine (OR = 4.153; 95% confidence interval (CI) = 2.182–7.902; p 0.001), (OR= 1.556; 95% CI = 1.007–2.404; p = 0.047), respectively. In the group with side effects after vaccination, more participants consumed low-fat dairy, compared to the control (p = 049). Conclusions: It seems that intake of yogurt and cheese can increase the odds of side effects after COVID-19 vaccination.