Abstract
BACKGROUND: The Omicron variant has heightened COVID- 19 infections among children under six, emphasizing the need to understand the role of parental immunization and demographic factors in disease transmission within households. METHODS: This retrospective observational study included 2321 children under six-year-old from February to May 2022 in Isfahan, Iran. Data were sourced from the recorded PERSIAN Birth Cohort data and telephone interviews, focusing on demographic information, child's COVID- 19 exposure during follow-up, infection, and vaccination status of each family member. RESULT: Out of 2321 children, the incidence rate of COVID- 19 during the sixth peak was determined to be 46%. Both maternal (X(2): 1237.0; p-value < 0.001) and paternal (X(2): 1003.1; p-value < 0.001) COVID- 19 infections were identified as significant risk factors for infection of children. Although paternal vaccination showed a statistically significant association with reduced infection rates among children (p = 0.036), maternal immunization did not demonstrate a significantly correlation. After Adjusting covariates, higher odds of child COVID- 19 incidence were associated with maternal infection (OR = 37.74, 95%CI: 24.86- 57.27), paternal infection (OR = 6.50,95% CI: 4.74-8.92), and maternal age older than 30 years old (odds ratio: 0.58, 95% CI: 0.49 to 0.68). Additionally, lower odds of infection were related to living at homes with optimal cleanness (odds ratio: 0.8, 95% CI: 0.6 to 0.9). Although in a crude model, the odds of infection of children in low-income families was 60% more than in moderate- or high-income families; this probability was not statistically significant in the adjusted model. CONCLUSION: This study underscores the significant role of parental transmission and paternal immunization in child COVID- 19 infections and the dimension of infection rates during the Omicron peak. Regarding the occupational conditions of fathers in our society and the characteristics of the COVID- 19 virus, paternal immunization should be prioritized over maternal immunization to mitigate disease transmission. Also, the sanitation of the home is crucial to prevent of risk of infection in children.