Natural immunity to influenza A and B among Saudi blood donors in Al Madinah Al Munawarah, Saudi Arabia

OBJECTIVES: To investigate the seroprevalence of influenza viruses (A and B) among blood donors in Kingdom of Saudi Arabia. METHODS: The present investigation was conducted between April 2019 and July 2019. Participants were healthy adults recruited from the central blood bank Al Madinah Al Munawarah, Kingdom of Saudi Arabia. Immunoglobulin G (IgG) levels against influenza A and B were measured in serum samples using ELISA. RESULTS: The results showed that 29.2% of the sample had significant concentrations of influenza A IgG antibody, whereas 38.6% had significant concentrations of influenza B IgG antibody. A strong correlation was found between the levels of influenza A and influenza B antibodies (r=0.708, p<0.001). The number of individuals identified as negative for influenza A IgG antibody increased with age (p<0.01). In addition, no correlations were identified between influenza A IgG and influenza B IgG and body mass index (BMI), (p>0.05). Finally, linear regression analysis showed that the level of influenza A antibody can be predicted by age (p<0.05) and body mass index (BMI) (p<0.05). CONCLUSION: Approximately one-third of Saudi Arabian adults presented significant levels of influenza A and B antibodies in our study. Demographic factors, including age and BMI, might contribute to influenza A antibody levels.