Assessing Public Health and Social Measures Against COVID-19 in Japan From March to June 2021

Abstract

BackgroundPublic 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 MethodsWe 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 (Rt) before and after these interventions, and then analyzed the relationship between lower Rt values and each PHSM.ResultsWith implementation of pre-emergency measures (PEM) in 16 prefectures, the Rt 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 Rt < 1, and the average relative reduction was 26%–39%. No single intervention was identified that uniquely resulted in an Rt value < 1.ConclusionAn SoE can substantially reduce the Rt 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 Rt value to < 1 in this study, but that may be partly attributable to the greater transmissibility of the Alpha variant.

Effectiveness of social distancing measures and lockdowns for reducing transmission of COVID-19 in non-healthcare, community-based settings

“…In Pakistan, a city that implemented complete school closures for 10 days saw a greater decline in incidence for the overall city population compared with a city that partially closed schools [217]. In the remaining 18 studies [22,27,36,45,49,50,[221][222][223][224][225][226][227][228][229][230][231][232], the effects of school closures were estimated alongside other interventions, making it challenging to isolate the individual effect of school closure strategies.…”

A large-scale machine learning study of sociodemographic factors contributing to COVID-19 severity

“…On the other hand, a significant advantage of our study is that the epidemic intervention decisions (social distancing, quarantine, etc.) that impact the disease spread (transmissibility) (Hayashi et al, 2022) do not influence our severity measure (Markovic et al, 2021). This is because our severity measure m/r is independent of transmissibility, which does not apply to measures commonly used to quantify COVID-19 severity/mortality (such as the number of fatalities).…”

Identifying High-Risk Events for COVID-19 Transmission: Estimating the Risk of Clustering Using Nationwide Data

“…Public health and social measures in Japan initially requested that social contacts and movements be uniformly reduced in the form of a state of emergency (SoE). As an alternative measure to the SoE, pre-emergency measures (PEMs) were introduced in early 2021, in which interventions were more customized and focused on high-risk settings [ 15 ] that are likely to meet the 3Cs concept. This included settings such as eating and drinking establishments that serve alcohol.…”

“…This included settings such as eating and drinking establishments that serve alcohol. PEMs allowed the local governor of the target area to decide which sub-regional areas would be subject to these customized interventions [ 15 ].…”