tetano
Editor, Senior Moderator
Int J Environ Res Public Health
. 2022 Mar 24;19(7):3889.
doi: 10.3390/ijerph19073889.
Increased Secondary Attack Rate among Unvaccinated Household Contacts of Coronavirus Disease 2019 Patients with Delta Variant in Japan
Tsuyoshi Ogata[SUP] 1 [/SUP], Hideo Tanaka[SUP] 2 [/SUP], Yumiko Nozawa[SUP] 1 [/SUP], Kazue Mukouyama[SUP] 1 [/SUP], Emiko Tanaka[SUP] 1 [/SUP], Natsumi Osaki[SUP] 1 [/SUP], Etsuko Noguchi[SUP] 1 [/SUP], Kayoko Seo[SUP] 1 [/SUP], Koji Wada[SUP] 3 [/SUP]
Affiliations
Abstract
This study aimed to elucidate the household secondary attack rate (HSAR) of the Delta variant in comparison to the Alpha variant, and evaluate the risk factors among unvaccinated household contacts of patients with coronavirus disease 2019 (COVID-19). We studied household contacts of index cases of COVID-19 infected with Delta (L452R mutation), Alpha (N501Y mutation), and wild strain from December 2020 through November 2021 in Itako, Japan. The HSARs of the entire household contact, and the contact of index case with Delta variant were calculated and compared across the risk factors. We used a generalized estimating equation regression model for the multivariate analysis. We enrolled 1257 unvaccinated contacts from 580 households. The HSAR was higher in household contacts of index patients with Delta (48.5%) than with Alpha variant (21.7%) (aOR = 3.34, p = 0.000). In Delta variants, the HSAR was higher in household contacts with spousal relationships to index patients (63.4%) than contacts with other relationships (45.5%) (aOR 1.94, p = 0.026), and was lower in household contacts of index patients aged ≤19 (33.1%) than for contacts of index cases aged 20-59 years (52.6%) (aOR = 0.50, p = 0.027). The result of our study can be used to devise informed strategy to prevent transmission within households.
Keywords: Alpha variant; COVID-19; Delta variant; Japan; SARS-CoV-2; household transmission; index patient; secondary attack rate; spouse; unvaccinated.
. 2022 Mar 24;19(7):3889.
doi: 10.3390/ijerph19073889.
Increased Secondary Attack Rate among Unvaccinated Household Contacts of Coronavirus Disease 2019 Patients with Delta Variant in Japan
Tsuyoshi Ogata[SUP] 1 [/SUP], Hideo Tanaka[SUP] 2 [/SUP], Yumiko Nozawa[SUP] 1 [/SUP], Kazue Mukouyama[SUP] 1 [/SUP], Emiko Tanaka[SUP] 1 [/SUP], Natsumi Osaki[SUP] 1 [/SUP], Etsuko Noguchi[SUP] 1 [/SUP], Kayoko Seo[SUP] 1 [/SUP], Koji Wada[SUP] 3 [/SUP]
Affiliations
- PMID: 35409572
- DOI: 10.3390/ijerph19073889
Abstract
This study aimed to elucidate the household secondary attack rate (HSAR) of the Delta variant in comparison to the Alpha variant, and evaluate the risk factors among unvaccinated household contacts of patients with coronavirus disease 2019 (COVID-19). We studied household contacts of index cases of COVID-19 infected with Delta (L452R mutation), Alpha (N501Y mutation), and wild strain from December 2020 through November 2021 in Itako, Japan. The HSARs of the entire household contact, and the contact of index case with Delta variant were calculated and compared across the risk factors. We used a generalized estimating equation regression model for the multivariate analysis. We enrolled 1257 unvaccinated contacts from 580 households. The HSAR was higher in household contacts of index patients with Delta (48.5%) than with Alpha variant (21.7%) (aOR = 3.34, p = 0.000). In Delta variants, the HSAR was higher in household contacts with spousal relationships to index patients (63.4%) than contacts with other relationships (45.5%) (aOR 1.94, p = 0.026), and was lower in household contacts of index patients aged ≤19 (33.1%) than for contacts of index cases aged 20-59 years (52.6%) (aOR = 0.50, p = 0.027). The result of our study can be used to devise informed strategy to prevent transmission within households.
Keywords: Alpha variant; COVID-19; Delta variant; Japan; SARS-CoV-2; household transmission; index patient; secondary attack rate; spouse; unvaccinated.