Potential impact of combined influenza and pneumococcal vaccines on the severity of respiratory illness in COVID-19 infection among type 2 diabetic patients

Abstract

To retrospectively assess the impact of regular yearly administration of recombinant influenza and single administration of pneumococcal conjugate vaccines on the occurrence of serious respiratory infection including COVID-19 in patients with type 2 diabetes mellitus. Hundred patients with type 2 diabetes mellitus were given Vaxigrip and Prevnar13® vaccines and were evaluated by comprehensive clinical review, airflow screening questionnaire, and routine laboratory investigations with follow-up during the COVID-19 pandemic and compared to a control group of diabetic patients with the same inclusion criteria (n = 100). After Vaxigrip and Prevnar13, there is a significant improvement in respiratory symptoms and a decrease in the airflow screening questionnaire (p = 0.0001) with a significant improvement in inflammatory parameters as neutrophil–lymphocyte ratio, ESR, CRP, and platelet count. Four patients had mild COVID-19 (4%), mainly gastrointestinal with no complications. Twenty-one out of 32 (65.6%) patients in the control group had severe COVID-19. The hazard ratios of significant respiratory tract infection and death due to COVID-19 were 2.29 and 10.24 in the non-vaccinated control (p = 0.001).The severity of COVID-19 in diabetes correlated with HBA1C (p = 0.007), combined Vaxigrip and Prevnar13 vaccination (p = 0.0001), serum creatinine (p = 0.001), neutrophil–lymphocyte ratio (p = 0.001), and thrombocytopenia (p = 0.003). The present study suggested that the combination of Prevnar13 and Vaxigrip may be related to decreased occurrence of serious respiratory infections including COVID-19. Further randomized control trials may be needed to establish a direct causation between the two and clarify these associations.