Factors associated with household transmission of SARS‐CoV‐2 omicron variant to health care workers: A retrospective cohort study
Keisuke Kagami, Reiko Oyamada, Tsubasa Watanabe, Sho Nakakubo, Takahiro Hayashi, Sumio Iwasaki, Tatsuya Fukumoto, Takayuki Usami, Kasumi Hayasaka, Shinichi Fujisawa, Chiaki Watanabe, Mutsumi Nishida, Takanori Teshima, Yusuke Niinuma, Isao Yokota, Yoh Takekuma, Mitsuru Sugawara, Nobuhisa Ishiguro- General Nursing
Abstract
Aim
The aim of this study was to determine the risk factors for household transmission of the omicron variant of SARS‐CoV‐2.
Background
The household infection rate has been reported to be higher for the omicron variant than for non‐omicron variants of SARS‐CoV‐2. Determination of the risk factors for household transmission of the omicron variant is therefore important.
Design
A Retrospective Cohort Study was conducted.
Methods
When family members of health care workers (HCWs) were found to be infected with SARS‐CoV‐2, the HCWs had to receive two nucleic acid amplification tests for SARS‐CoV‐2: immediately after and 5 to 10 days after the onset of COVID‐19 in the family members. Risk factors of household transmission were analysed by comparing cases (HCWs infected with SARS‐CoV‐2) and controls (HCWs not infected with SARS‐CoV‐2) using multivariable analysis.
Results
Unvaccinated status (OR: 3.97), age of index cases (≤6 years) (OR: 1.94) and staying at home with index cases (OR: 10.18) were risk factors for household transmission.
Conclusion
If there is a strong desire to avoid household infection, family members infected with SARS‐CoV‐2 should live separately during the period of viral shedding.