Household secondary attack rates and risk factors during periods of SARS-CoV-2 Delta and Omicron variant predominance in the Republic of Korea
10.24171/j.phrp.2023.0133
- Author:
Jin LEE
1
;
Mijeong KO
;
Seontae KIM
;
Dosang LIM
;
Gemma PARK
;
Sang-Eun LEE
Author Information
1. Central Disease Control Headquarters, Korea Disease Control and Prevention Agency, Cheongju, Republic of Korea
- Publication Type:Original Article
- From:
Osong Public Health and Research Perspectives
2023;14(4):263-271
- CountryRepublic of Korea
- Language:English
-
Abstract:
Objectives:The household secondary attack rate (SAR) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important indicator for community transmission. This study aimed to characterize transmission by comparing household SARs and identifying risk factors during the periods of Delta and Omicron variant predominance in Republic of Korea.
Methods:We defined the period of Delta variant predominance (Delta period) as July 25, 2021 to January 15, 2022, and the period of Omicron variant predominance (Omicron period) as February 7 to September 3, 2022. The number of index cases included was 214,229 for the Delta period and 5,521,393 for the Omicron period. To identify the household SARs and risk factors for each period, logistic regression was performed to determine the adjusted odds ratio (aOR).
Results:The SAR was 35.2% for the Delta period and 43.1% for the Omicron period. The aOR of infection was higher in 2 groups, those aged 0 to 18 years and ≥75 years, compared to those aged 19 to 49 years. Unvaccinated individuals (vs. vaccinated individuals) and individuals experiencing initial infection (vs. individuals experiencing a second or third infection) had an increased risk of infection with SARS-CoV-2.
Conclusion:This study analyzed the household SARs and risk factors. We hope that the
results:can help develop age-specific immunization plans and responses to reduce the SAR in preparation for emerging infectious diseases or potential new variants of SARS-CoV-2.
