Effects of voluntary event cancellation and school closure as countermeasures against COVID-19 outbreak in Japan

Non-Pharmacologic Interventions in COVID-19 Pandemic Management; a Systematic Review

Introduction

Different countries throughout the world have adopted non-pharmacologic interventions to reduce and control SARS - CoV-2. In this systematic approach, the impact of non-pharmacologic interventions in management of COVID-19 pandemic was assessed.

Methods

Following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, systematic search was carried out on the basis of a search strategy on PubMed, Web of Science, Scopus, and WHO databases on COVID-19. The impact of travel ban, personal protective equipment, distancing, contact tracing, school closure, and social distancing and the combined effect of interventions on COVID-19 were assessed.

Results

Of the 14,857 articles found, 44 were relevant. Studies in different countries have shown that various non-pharmacological interventions have been used during the COVID-19 pandemic. The travel ban, either locally or internationally in most of the countries, movement restriction, social distancing, lockdown, Personal Protective Equipment (PPE), quarantine, school closure, work place closure, and contact tracing had a significant impact on the reduction of mortality or morbidity of COVID-19.

Conclusion

Evidence shows that the implementation of non-pharmacologic interventions (NPIs), for this study suggests that the effectiveness of any NPI alone is probably limited, thus, a combination of various actions, for example, social distancing, isolation, and quarantine, distancing in the workplace and use of personal protective equipment, is more effective in reducing COVID-19.

Decreased community-acquired pneumonia coincided with rising awareness of precautions before governmental containment policy in Japan

The effectiveness of population-wide compliance to personal precautions (mask-wearing and hand hygiene) in preventing community-acquired pneumonia has been unknown. In Japan, different types of nonpharmaceutical interventions from personal precautions to containment and closure policies (CACPs, e.g. stay-at-home requests) were sequentially introduced from late January to April 2020, allowing for separate analysis of the effects of personal precautions from other more stringent interventions. We quantified the reduction in community-acquired pneumonia hospitalizations and deaths and assessed if it coincided with the timing of increased public awareness of personal precautions before CACPs were implemented. A quasi-experimental interrupted time-series design was applied to non-COVID-19 pneumonia hospitalization and 30-day death data from April 2015 to August 2020 across Japan to identify any trend changes between February and April 2020. We also performed a comparative analysis of pyelonephritis and biliary tract infections to account for possible changes in the baseline medical attendance. These trend changes were then compared with multiple indicators of public awareness and behaviors related to personal precautions, including keyword usage in mass media coverage and sales of masks and hand hygiene products. Hospitalizations and 30-day deaths from non-COVID-19 pneumonia dropped by 24.3% (95% CI 14.8-32.8) and 16.1% (5.5-25.5), respectively, in February 2020, before the implementation of CACPs, whereas pyelonephritis and biliary tract infections did not suggest a detectable change. These changes coincided with increases in indicators related to personal precautions rather than those related to contact behavior changes. Community-acquired pneumonia could be reduced by population-wide compliance to moderate precautionary measures.

COVID-19 in Japan, January-March 2020: insights from the first three months of the epidemic

BACKGROUND

Understanding the characteristics and natural history of novel pathogens is crucial to inform successful control measures. Japan was one of the first affected countries in the COVID-19 pandemic reporting their first case on 14 January 2020. Interventions including airport screening, contact tracing, and cluster investigations were quickly implemented. Here we present insights from the first 3 months of the epidemic in Japan based on detailed case data.

METHODS

We conducted descriptive analyses based on information systematically extracted from individual case reports from 13 January to 31 March 2020 including patient demographics, date of report and symptom onset, symptom progression, travel history, and contact type. We analysed symptom progression and estimated the time-varying reproduction number, Rt, correcting for epidemic growth using an established Bayesian framework. Key delays and the age-specific probability of transmission were estimated using data on exposures and transmission pairs.

RESULTS

The corrected fitted mean onset-to-reporting delay after the peak was 4 days (standard deviation: ± 2 days). Early transmission was driven primarily by returning travellers with Rt peaking at 2.4 (95% CrI: 1.6, 3.3) nationally. In the final week of the trusted period (16-23 March 2020), Rt accounting for importations diverged from overall Rt at 1.1 (95% CrI: 1.0, 1.2) compared to 1.5 (95% CrI: 1.3, 1.6), respectively. Household (39.0%) and workplace (11.6%) exposures were the most frequently reported potential source of infection. The estimated probability of transmission was assortative by age with individuals more likely to infect, and be infected by, contacts in a similar age group to them. Across all age groups, cases most frequently onset with cough, fever, and fatigue. There were no reported cases of patients < 20 years old developing pneumonia or severe respiratory symptoms.

CONCLUSIONS

Information collected in the early phases of an outbreak are important in characterising any novel pathogen. The availability of timely and detailed data and appropriate analyses is critical to estimate and understand a pathogen's transmissibility, high-risk settings for transmission, and key symptoms. These insights can help to inform urgent response strategies.

Associations between components of household expenditures and the rate of change in the number of new confirmed cases of COVID-19 in Japan: Time-series analysis

Background

Social distancing measures to prevent the spread of COVID-19 included restrictions on retail services in many countries. In some countries, the governments also subsidized consumer spending on part of retail services to help struggling businesses. To evaluate the costs and benefits of government interventions in retail services, it is necessary to measure the infectiousness of each type of consumer activity.

Methods

This study regresses the log difference over seven days in the number of new confirmed cases of COVID-19 in Japan on lagged values of household expenditures per household on eating out, traveling, admissions to entertainment facilities, clothing and footwear, and the other items, as well as a measure of mobility in public transportation in the past 14 days. The sample period of the dependent variable is set from March 1, 2020, to February 1, 2021, in order to avoid a possible structural break due to the spread of mutant strains in 2021. The regression model is estimated by the Bayesian method with a non-informative (improper) prior. The estimated model is evaluated by out-of-sample forecast performance from February 2, 2021, onward.

Results

The out-of-sample forecasts of the regression by the posterior means of regression coefficients perform well before the spread of the Delta variant in Japan since June 2021. R² for the out-of-sample forecasts from February 2, 2021, to June 30, 2021, is 0.60. The dependent variable of the regression overshot the out-of-sample forecasts from mid-June to August 2021. Then, the out-of-sample forecasts overpredicted the dependent variable for the rest of 2021.

Conclusion

The estimated model can be potentially useful in simulating changes in the number of new confirmed cases due to household spending on retail services, if it can be adjusted to real-time developments of mutant strains and vaccinations. Such simulations would help in designing cost-efficient government interventions.

Waning COVID-19 vaccine effectiveness in Japan

As of the end of November, 2021, the rate of completion for second-dose COVID-19 vaccine administration was almost 80% in Japan. We evaluated waning COVID-19 vaccine effectiveness in Japan, controlling for mutated strains, the Olympic Games, and countermeasures. The effective reproduction number R(t) was regressed on current vaccine coverage and data of a certain number of days prior, as well as shares of mutated strains, and an Olympic Games dummy variable along with data of temperature, humidity, mobility, and countermeasures. The study period was February, 2020 through November 4, as of November 25, 2021. Estimation results indicate that vaccine coverage of more than 90 days prior raises R(t) significantly. Especially, vaccine coverage with 90 or 120 days prior cancelled vaccine effectiveness completely. Results indicate significant waning of vaccine effectiveness from 90 days after the second dose.

A review on COVID-19 transmission, epidemiological features, prevention and vaccination

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused hundreds of millions of infections and millions of deaths over past two years. Currently, many countries have still not been able to take the pandemic under control. In this review, we systematically summarized what we have done to mitigate the COVID-19 pandemic, from the perspectives of virus transmission, public health control measures, to the development and vaccination of COVID-19 vaccines. As a virus most likely coming from bats, the SARS-CoV-2 may transmit among people via airborne, faecal-oral, vertical or foodborne routes. Our meta-analysis suggested that the R₀ of COVID-19 was 2.9 (95% CI: 2.7–3.1), and the estimates in Africa and Europe could be higher. The median R_t could decrease by 23–96% following the nonpharmacological interventions, including lockdown, isolation, social distance, and face mask, etc. Comprehensive intervention and lockdown were the most effective measures to control the pandemic. According to the pooled R₀ in our meta-analysis, there should be at least 93.3% (95% CI: 89.9–96.2%) people being vaccinated around the world. Limited amount of vaccines and the inequity issues in vaccine allocation call for more international cooperation to achieve the anti-epidemic goals and vaccination fairness.