Public health responses to COVID-19 in Japan.

Two years have passed since the confirmation of the first case of coronavirus disease (COVID-19) in Japan. The aim of this article was to review the public health responses to COVID-19 in Japan. As of January 31, 2022, COVID-19-positive cases have cumulatively totaled 2,669,638 and deaths cases have cumulatively totaled 18,784. To deter COVID-19 transmission in the community, the government declared a state of emergency to minimize the impact on people's livelihoods and the economy. The prefectural (province) governor of an area under a "State of Emergency" may request special action to prevent the spread of infection among residents. A nationwide campaign, Avoid the "3 Cs" (Closed spaces, Crowded spaces, and Close-contact settings), has been widely acknowledged to have controlled infection in high-risk areas. In Japan, COVID-19 vaccines were supplied by Pfizer, Moderna, and AstraZeneca. Pfizer's vaccine received regulatory approval in Japan in February 2021, and Moderna and AstraZeneca's did so in May 2021. Public health centers (PHCs) under the jurisdiction of local governments are responsible for conducting Polymerase Chain Reaction (PCR) testing, coordinating the treatment of COVID-19-positive patients, and identifying persons in close contact with COVID-19 patients through an epidemiological study of each positive case. These public health responses have been implemented based on the assessment of the impact of each variant and support from a government panel of experts. Further studies may be need to be conducted develop more flexible and efficient public health responses.

Increased Secondary Attack Rates among the Household Contacts of Patients with the Omicron Variant of the Coronavirus Disease 2019 in Japan.

This study investigated the household secondary attack rate (HSAR) of patients with coronavirus disease (COVID-19) during the omicron variant-dominant period. The HSAR of COVID-19 cases during the omicron variant-dominant period (4-20 January 2022) was calculated and compared with the delta variant-dominant period (20 August to 7 November 2021) in Itako, Japan. In Itako, all 47 and 119 samples tested during the omicron and delta variant-dominant periods were negative and positive, respectively, for the L452R mutation. We used a generalized estimating equation regression model. The HSAR was 31.8% (95% confidence interval (CI) 27.7-36.2) for 456 household contacts during the omicron variant-dominant period; it was higher than that during the delta variant-dominant period (25.2%) (adjusted risk ratio [aRR] 1.61, CI 1.13-2.28). During the omicron variant-dominant period, HSAR was lower for the household contacts of completely vaccinated index patients (27.3%) than for contacts of other index patients (41.2%) (vaccine effectiveness for infectee 0.43, 95% CI 0.16-0.62) and was significantly higher for female contacts than for male contacts (36.2% vs. 26.1%; aRR 1.29, 95% CI 1.01-1.65). The HSAR was significantly higher during the omicron variant-dominant period than the delta variant-dominant period. The vaccination of index patients might protect household contacts.

Contributions of the Medical Affairs Department to Healthcare Professionals and the Effects of the New Coronavirus Disease 2019 Pandemic on the Contributions

Objective: The purpose of this study was to assess the opinions of healthcare professional regarding the contributions of the Medical Affairs department. Furthermore, we aimed to identify factors influencing and reasons for the contributions in the new coronavirus disease 2019 (COVID-19) pandemic situation. Design/Methods: A web-based survey was conducted among healthcare professionals (Key Opinion Leader/Key Thought Leader, KOL/KTL) who had multiple contacts with the Medical Affairs department, Japan. Results: The responses of 141 KOL/KTLs in Japan were collected;77.3% of the respondents indicated that the contributions of the Medical Affairs department exceeded their expectations (achieved the expected level of contribution). The most common responses were “the identification of unmet medical needs” and “the dissemination of medical and scientific information, providing advanced medical and scientific information;” other responses included “promoting sales of the company's drugs.” The requests from KOL/KTLs regarding quality were “knowledge about biological and clinical statistics” and “proposal and quick response ability from the perspective of medical staff and patients,” but these responses were partially different between physicians and pharmacists. COVID-19 has resulted in substantial changes, for example, “face-to-face” interactions have significantly decreased from 91.5 to 50.4% and “Online” interactions have significantly increased from 20.6 to 70.9%. However, the effects of the declaration of emergency state could not be identified. The KOL/KTLs requested to make the meeting times more appropriate, conduct in-depth two-way discussions, provide latest information, and discuss about professional manners and behaviors. Conclusion: In summary, regardless of the changes in the types of activities caused by COVID-19, the Medical Affairs department has made substantial contributions to healthcare professionals, who highly appreciated them. Furthermore, depending on responses of individuals whose expectations could not be met, areas of improvements have been suggested.

Increased Secondary Attack Rate among Unvaccinated Household Contacts of Coronavirus Disease 2019 Patients with Delta Variant in Japan.

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.

Increased Secondary Attack Rate among Unvaccinated Household Contacts of Coronavirus Disease 2019 Patients with Delta Variant in Japan

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.

Proactive Engagement of the Expert Meeting in Managing the Early Phase of the COVID-19 Epidemic, Japan, February-June 2020.

To deal with the risk of emerging diseases with many unknowns, close and timely collaboration and communication between science experts and policymakers are crucial to developing and implementing an effective science-based intervention strategy. The Expert Meeting, an ad hoc medical advisory body, was established in February 2020 to advise Japan's COVID-19 Response Headquarters. The group played an important role in the policymaking process, promoting timely situation awareness and developing science-based proposals on interventions that were promptly reflected in government actions. However, this expert group may have been overly proactive in taking on the government's role in crisis management. For the next stage of managing the coronavirus disease pandemic and future pandemics, the respective roles of the government and its advisory bodies need to be clearly defined. Leadership and strategic risk communication by the government are key.

Secondary Attack Rate among Non-Spousal Household Contacts of Coronavirus Disease 2019 in Tsuchiura, Japan, August 2020-February 2021.

Household secondary attack rate (HSAR) by risk factor might have a higher transmission rate between spouses. We investigated risk factors for the HSAR among non-spousal household contacts of patients with coronavirus disease 2019 (COVID-19). We studied household contacts of index cases of COVID-19 in Tsuchiura, Japan, from August 2020 through February 2021. The HSARs of the whole household contacts and non-spousal household contacts were calculated and compared across risk factors. We used a generalized linear mixed regression model for multivariate analysis. We enrolled 496 household contacts of 236 index COVID-19 cases. The HSAR was higher for spousal household contacts (37.8%) than for other contacts (21.2%). The HSAR was lower for non-spousal household contacts with a household size (number of household members) of two (18.2%), compared to the HSAR for contacts with a household size ≥4. The HSAR was higher for non-spousal household contacts of index patients with ≥3 days of diagnostic delay (period between onset and diagnosis) (26.0%) compared to those with ≤2 days' delay (12.5%) (p = 0.033). Among non-spousal household contacts, the HSAR was low for those with a household size of two and was high for contacts of index patients with a long diagnostic delay.

Infection and transmission of COVID-19 among students and teachers in schools in Japan after the reopening in June 2020.

We aimed to investigate the confirmed COVID-19 cases among students and teachers in elementary schools (ages 6-12 years) and junior high schools (ages 13-15 years) in Japan between 1 June and 31 July 2020. We requested all schools to provide reports when students or teachers tested positive for COVID-19. A total of 207 cases were reported among students. Household transmission was identified as the dominant transmission route, confirmed in 71.4% of elementary schools and 60.3% of junior high schools. A total of 39 cases were reported among teachers, of which transmission route was unknown in 72.4% of elementary schools and 90.0% of junior high schools.

Environmental Sampling for Severe Acute Respiratory Syndrome Coronavirus 2 During a COVID-19 Outbreak on the Diamond Princess Cruise Ship.

During a COVID-19 outbreak on the Diamond Princess cruise ship we sampled environmental surfaces after passengers and crew vacated cabins. SARS-CoV-2 RNA was detected in 58 of 601 samples (10%) from case cabins 1-17 days after cabins were vacated but not from noncase cabins. There was no difference in detection proportion between cabins of symptomatic (15%, 28/189; cycle quantification [Cq], 29.79-38.86) and asymptomatic cases (21%, 28/131; Cq, 26.21-38.99). No SARS-CoV-2 virus was isolated from any of the samples. Transmission risk of SARS-CoV-2 from symptomatic and asymptomatic patients may be similar and surfaces could be involved in transmission.

Japanese citizens' behavioral changes and preparedness against COVID-19: An online survey during the early phase of the pandemic.

The Japanese government instituted countermeasures against COVID-19, a pneumonia caused by the new coronavirus, in January 2020. Seeking "people's behavioral changes," in which the government called on the public to take precautionary measures or exercise self-restraint, was one of the important strategies. The purpose of this study is to investigate how and from when Japanese citizens have changed their precautionary behavior under circumstances in which the government has only requested their cooperation. This study uses micro data from a cross-sectional survey conducted on an online platform of an online research company, based on quota sampling that is representative of the Japanese population. By the end of March 2020, a total of 11,342 respondents, aged from 20 to 64 years, were recruited. About 85 percent reported practising the social distancing measures recommended by the government including more females than males and more older than younger participants. Frequent handwashing is conducted by 86 percent of all participants, 92 percent of female, and 87.9 percent of over-40 participants. The most important event influencing these precautionary actions was the infection aboard the Diamond Princess cruise ship, which occurred in early February 2020 (23 percent). Information from the central and local governments, received by 60 percent of the participants, was deemed trustworthy by 50 percent. However, the results also showed that about 20 percent of the participants were reluctant to implement proper prevention measures. The statistical analysis indicated that the typical characteristics of those people were male, younger (under 30 years old), unmarried, from lower-income households, a drinking or smoking habit, and a higher extraversion score. To prevent the spread of infection in Japan, it is imperative to address these individuals and encourage their behavioural changes using various means to reach and influence them.