RT Journal Article SR Electronic T1 Natural immunity to influenza A and B among Saudi blood donors in Al Madinah Al Munawarah, Saudi Arabia JF Saudi Medical Journal JO Saudi Med J FD Prince Sultan Military Medical City SP 1301 OP 1307 DO 10.15537/smj.2020.12.05582 VO 41 IS 12 A1 Mahallawi, Waleed H. A1 Ibrahim, Nadir A. A1 Alahmadi, Khalid S. A1 Al-Harbi, Abdullah K. A1 Almughthawi, Mohammed A. A1 Alhazmi, Omar A. A1 Alsehli, Fayez H. A1 Khabour, Omar F. YR 2020 UL http://smj.org.sa/content/41/12/1301.abstract AB 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.