tetano
Editor, Senior Moderator
Front Med (Lausanne)
. 2022 Jul 12;9:937732.
doi: 10.3389/fmed.2022.937732. eCollection 2022.
Assessing Public Health and Social Measures Against COVID-19 in Japan From March to June 2021
Katsuma Hayashi[SUP] 1 [/SUP], Taishi Kayano[SUP] 1 [/SUP], Asami Anzai[SUP] 1 [/SUP], Marie Fujimoto[SUP] 1 [/SUP], Natalie Linton[SUP] 1 [/SUP], Misaki Sasanami[SUP] 1 [/SUP], Ayako Suzuki[SUP] 1 [/SUP], Tetsuro Kobayashi[SUP] 1 [/SUP], Kanako Otani[SUP] 2 [/SUP], Masato Yamauchi[SUP] 2 [/SUP], Motoi Suzuki[SUP] 2 [/SUP], Hiroshi Nishiura[SUP] 1 [/SUP]
Affiliations
Abstract
Background: Public health and social measures (PHSM) against COVID-19 in Japan involve requesting the public to voluntarily reduce social contact; these measures are not legally binding. The effectiveness of such PHSM has been questioned with emergence of the SARS-CoV-2 Alpha variant (B.1.1.7), which exhibited elevated transmissibility.
Materials and methods: We investigated the epidemic dynamics during the fourth epidemic wave in Japan from March to June 2021 involving pre-emergency measures and declaration of a state of emergency (SoE). We estimated the effective reproduction number (R [SUB]t[/SUB] ) before and after these interventions, and then analyzed the relationship between lower R [SUB]t[/SUB] values and each PHSM.
Results: With implementation of pre-emergency measures (PEM) in 16 prefectures, the R [SUB]t[/SUB] was estimated to be < 1 in six prefectures; its average relative reduction ranged from 2 to 19%. During the SoE, 8 of 10 prefectures had an estimated R [SUB]t[/SUB] < 1, and the average relative reduction was 26%-39%. No single intervention was identified that uniquely resulted in an R [SUB]t[/SUB] value < 1.
Conclusion: An SoE can substantially reduce the R [SUB]t[/SUB] and may be required to curb a surge in cases caused by future SARS-CoV-2 variants of concern with elevated transmissibility. More customized interventions did not reduce the R [SUB]t[/SUB] value to < 1 in this study, but that may be partly attributable to the greater transmissibility of the Alpha variant.
Keywords: Infectious Disease; coronavirus; effective reproduction number; mathematical model; modeling; statistical estimation.
. 2022 Jul 12;9:937732.
doi: 10.3389/fmed.2022.937732. eCollection 2022.
Assessing Public Health and Social Measures Against COVID-19 in Japan From March to June 2021
Katsuma Hayashi[SUP] 1 [/SUP], Taishi Kayano[SUP] 1 [/SUP], Asami Anzai[SUP] 1 [/SUP], Marie Fujimoto[SUP] 1 [/SUP], Natalie Linton[SUP] 1 [/SUP], Misaki Sasanami[SUP] 1 [/SUP], Ayako Suzuki[SUP] 1 [/SUP], Tetsuro Kobayashi[SUP] 1 [/SUP], Kanako Otani[SUP] 2 [/SUP], Masato Yamauchi[SUP] 2 [/SUP], Motoi Suzuki[SUP] 2 [/SUP], Hiroshi Nishiura[SUP] 1 [/SUP]
Affiliations
- PMID: 35903315
- PMCID: PMC9315273
- DOI: 10.3389/fmed.2022.937732
Abstract
Background: Public health and social measures (PHSM) against COVID-19 in Japan involve requesting the public to voluntarily reduce social contact; these measures are not legally binding. The effectiveness of such PHSM has been questioned with emergence of the SARS-CoV-2 Alpha variant (B.1.1.7), which exhibited elevated transmissibility.
Materials and methods: We investigated the epidemic dynamics during the fourth epidemic wave in Japan from March to June 2021 involving pre-emergency measures and declaration of a state of emergency (SoE). We estimated the effective reproduction number (R [SUB]t[/SUB] ) before and after these interventions, and then analyzed the relationship between lower R [SUB]t[/SUB] values and each PHSM.
Results: With implementation of pre-emergency measures (PEM) in 16 prefectures, the R [SUB]t[/SUB] was estimated to be < 1 in six prefectures; its average relative reduction ranged from 2 to 19%. During the SoE, 8 of 10 prefectures had an estimated R [SUB]t[/SUB] < 1, and the average relative reduction was 26%-39%. No single intervention was identified that uniquely resulted in an R [SUB]t[/SUB] value < 1.
Conclusion: An SoE can substantially reduce the R [SUB]t[/SUB] and may be required to curb a surge in cases caused by future SARS-CoV-2 variants of concern with elevated transmissibility. More customized interventions did not reduce the R [SUB]t[/SUB] value to < 1 in this study, but that may be partly attributable to the greater transmissibility of the Alpha variant.
Keywords: Infectious Disease; coronavirus; effective reproduction number; mathematical model; modeling; statistical estimation.