The first case of infection in Japan occurred on January 15, 2020, in Kanagawa Prefecture. Since that time, measures have primarily focused on borderline control, including those for returnees from Wuhan and the Diamond Princess. In addition, the Ministry of Health, Labor and Welfare (hereinafter, MHLW) established a surveillance system, formulated guidelines for proactive epidemiological surveillance, and prepared for the establishment of a PCR testing system and a medical care supply system. The Headquarters for COVID-19 Control within the MHLW, as well as the Prime Minister's Office headed by the Prime Minister was established. In addition, an Advisory Board and the Expert Council on COVID-19 were set up to obtain advice from experts.

In April, the spread of the infection showed no sign of abating, and on April 7, the first state of emergency was declared, and emergency measures were implemented in some prefectures, including Tokyo and Osaka, etc. On April 15, the scope of the emergency measures was expanded nationwide. After reaching a peak of 644 daily cases on April 11, the number of cases began to decline, and on May 25, the emergency declaration was lifted. This outbreak was later referred to as the first wave.

The second wave arrived in August, the third in winter, the fourth in spring 2021, the fifth in summer, the sixth in winter to spring 2022, and the seventh in summer. During this period, the virus mutated and spread throughout the world.

From the beginning of 2020, efforts were made to develop vaccines and medicines. Since it was anticipated that there would be a battle among countries for the vaccine, discussions with foreign vaccine manufacturers began in the summer and a contract was concluded. As a result, vaccination of healthcare workers began in February 2021, followed by the expansion of vaccination to the elderly and those with underlying diseases, while establishing vaccination systems in municipal governments, and the second, third, and fourth doses were administered to a large number of citizens.

The number of cases of infection and deaths per population has thus far remained significantly lower than in other industrialized countries. This paper reviews the various responses implemented by the government, including the initial response, organization and governance, borderline control measures, surveillance, proactive epidemiological investigation, public health center system, laboratory system, medical supply system, vaccines, drugs, and public information and risk communication, and summarizes the lessons learned.

Public Health Centers of Japan, of which there are 468 across the country as of April 2022, are at the core of health crisis management, responding to natural disasters and infectious diseases according to the Community Health Act (1994). Under the Infectious Diseases Control Law, these centers have made repeated efforts to respond to COVID-19 from the first to the seventh waves, while epidemic dynamics changed, variants emerged, and pathogenicity fluctuated. All centers essentially play a common role in infectious disease control (answering questions and consultations, testing, registering cases, coordinating healthcare, transporting confirmed patients, following up with patients and close contacts, carrying out epidemiological investigations, issuing notifications for recommendations on hospital stays and work restrictions, etc.). However, due to the varying number of cases and healthcare resources depending on the region, the actual work was not identical, and local governments, which operate the centers, took different approaches.

Looking back on the epidemic, the first, second, and third waves saw travel restrictions implemented across the country, and were characterized by a demand for testing that exceeded capacity. At that time, COVID-19 was a threat to the respiratory system, no effective treatment or vaccination was available, and the number of healthcare institutions diagnosing and treating cases was inadequate. The fourth wave saw the Alpha variant ripping through nursing homes, putting a significant burden on healthcare, while the fifth wave saw the Delta variant spreading mainly from Tokyo after the Olympics. The sixth and seventh waves came with the highly-contagious Omicron variant, leading to skyrocketing patient numbers and the public health capacity quickly being overwhelmed. Local governments considered ways to reduce the burden on Public Health Centers, including outsourcing. Over this 2.5 year period, numerous advisories were issued by the Ministry of Health, Labor, and Welfare (MHLW), and the Japanese Association of Public Health Center Directors has advocated actively on behalf of the centers.

Given that Japan is a disaster-prone country, Public Health Centers in Japan are expected to play a pivotal role in crisis preparedness, responses to, and recovery from natural disasters and infectious diseases. As a coordination hub to protect lives and maintain health, here we strongly suggest that public health centers implement the lessons learned from COVID-19 to collaborate with healthcare institutions and long-term care facilities, and evolve into a sustainable social framework to advance pandemic preparedness in their respective communities.

SARS-CoV-2 is transmitted through respiratory droplets. Therefore, limiting close contact between people has been key in reducing the spread of the infection. This article aims to summarize the infection prevention measures implemented in our country between 2020 and the first half of 2022, and the associated lessons. The government discussed mitigation measures at the individual and societal levels, such as the declaration of a state of emergency, which strictly limits social contact and can have an economic impact. The government introduced the “Basic Policies for Novel Coronavirus Disease Control” at the societal level, as a framework for the overall COVID-19 countermeasure strategy. The government’s strategy involved issuing messages that resonate with the people, and providing new and updated information to promote behavioral changes. Prevention measures at the individual level included avoiding the “Three Cs (avoiding closed spaces, crowded places, and close-contact settings)” and wearing masks. During nationwide rapid infection surges, which significantly impacted people’s livelihoods and the economy, the state of emergency included stay-at-home requests. Furthermore, after the SARS-CoV-2 outbreak, the law was amended to add quasi-emergency measures to compensate for the limitations of the state of emergency. It was preferable for such stringent measures to be implemented early and only for a short time. However, the public and politicians were usually convinced of the necessity of these measures only after problems had gained a certain degree of recognition, and therefore, implementation was often delayed. Delays in mitigation led to the spread of the infection, which could require several weeks to several months before the infections declined or the number of seriously ill cases decreased sufficiently to alleviate the strain on hospital beds. The state of emergency and social distancing had a significant impact on our society. Economically, for example, the GDP dropped, and the effects on the food service industry and the hotel industry were devastating. Furthermore, the numbers of new marriages and births were also affected. Public funds were spent on various economic measures implemented by the government. We are currently awaiting an economic evaluation of the effectiveness of these measures. We must continue to plan and deliberate practical steps to prepare for new variants and the next pandemic. However, these challenges may be suitably met if multi-disciplinary stakeholders, especially politicians and the government, get involved.

Nucleic acid amplification tests for coronavirus diseases (COVID-19) were nearly established by the end of January 2020, mainly at regional Public Health Laboratories (PHLs) nationwide. Initially, the nucleic acid amplification test was a combination of conventional PCR and sequencing, in accordance with the pathogen detection manual of the National Institute of Infectious Diseases (NIID). However, this was soon changed to a real-time PCR method (NIID method), and test reagents were distributed by the NIID. In order to cope with the further increase in the number of tests, private laboratories began testing for novel coronaviruses in March, and PHLs cooperated with the launch of testing by private laboratories. Subsequently, a large variety of test reagents that replaced the NIID method were approved by the Ministry of Health, Labour and Welfare as in vitro diagnostic products.

In December 2020, highly infectious variants of SARS-CoV-2 emerged, and the PHL also became involved in screening tests and genome analysis to identify and analyze the alpha strain and other strains specified as Variants of Concern (VOC) by the World Health Organization (WHO). The epidemic that followed was characterized by a replacement of the initial variant with new variants, and the PHL also added SARS-CoV-2 whole-genome analysis using next-generation sequencers (NGS) and variant surveillance via real-time PCR to its work. This manuscript outlines the events of the past three years, including the establishment of Nucleic acid amplification tests at PHLs and our response to new variants.

One characteristic of the healthcare structure in Japan is that, compared with other Organization for Economic Co-operation and Development (OECD) countries, fewer substantive acute phase beds are available to handle highly complex pathologies, and there are fewer assigned healthcare personnel. In addition, Japan's population is aging at one of the highest rates in the world, and its healthcare system has been structured with an emphasis on treating the elderly and long-term chronic conditions. It has traditionally also lacked a mechanism to force doctors and nurses to engage in specific practices, and has struggled to deal with infectious disease pandemics. Based on the lessons learned in handling the outbreak on the Diamond Princess cruise ship that occurred in February 2020, a system for dealing with infectious disease pandemics has been developed. However, a comprehensive and justly proportional system for the provision of healthcare, including the provision of outpatient services, medical interventions for home care patients and patients in elderly welfare facilities, and healthcare provision for patients with comorbid COVID-19 has yet to be sufficiently established. As ensuring hospital beds when there is a rapidly increasing demand for hospitalization during the spread of infections remains an issue, measures have been taken such as the conclusion of agreements related to ensuring beds, a review of hospitalization criteria and ensuring beds with “rearward” acceptance, and the participation of community medicine in health observations of home care patients. However, while the characteristics of the virus were gradually becoming clear, and vaccines and treatment methods were being developed, COVID-19 could not be positioned as one among the myriad types of disease, and many problems surfaced.

As lessons from the experience of COVID-19 and measures for the future, investigations are needed based on the thinking of health risk management. It is therefore necessary to prepare and develop systems for dealing immediately with emergencies in which maintaining people's health may become difficult. The implementation of a health security system that involves national to local governments, which already have the best healthcare provision systems, is absolutely essential. The information sharing infrastructure and how to best communicate with citizens have been issues in this pandemic, and efforts that include expertise from outside the healthcare system are needed.

In response to the epidemic, a COVID-19 vaccine was developed at an unprecedented speed, and vaccination was carried out on an unprecedented scale.

The COVID-19 vaccination project consists of three fields: science, logistics/practice, and policy, and is the culmination of various attempts among these fields. First, in the field of science, vaccine development, examination/approval, and evaluation of adverse reactions, etc. are carried out. It was necessary to evaluate and verify safety as well as efficacy. Second, in the field of logistics/administration, it is extremely important to secure, supply, and distribute the vaccine, and to build a vaccine administration and execution system. Since the lead time is very long, it was necessary to proceed with preparations while adopting a future outlook. Third, policy decisions were made regarding the construction of a legal framework and the start of vaccinations. In addition, it was very important to appropriately conduct publicity and risk communication, as it is the general public who make the decision to receive the vaccination, in the end.

In this article, I will explain the overall picture of the COVID-19 vaccination project, which consists of these fields, while mentioning various specific attempts to implement the project throughout Japan.

Since the first report of the outbreak of a viral pneumonia of unknown cause in Wuhan, China at the end of 2019, the global community has been engaged in confronting a pandemic of the novel coronavirus infection for two years and nine months (roughly 1,000 days), up to the present. In Japan, public health responses such as non-pharmaceutical interventions, emergency measures, an expansion of the public health care system, and mass vaccination have been implemented to address various issues that have arisen in repeated waves. This article provides a timeline of the key public health events and measures that have been taken, mainly by the national government in Japan.

Objectives: In April 2020, a state of emergency was declared regarding COVID-19, and refraining from going out was requested. Although there is concern about weight gain after the spread of the infection, there are few reports of studies in Japan. The present study examined the association between refraining from going out and weight gain after the spread of COVID-19 infection.

Methods: Cross-sectional and longitudinal analyses were conducted. Cross-sectional: Data from an internet survey conducted in August 2020 among the general population in Japan were used. Of the 25482 valid responses, 18116 persons aged 20-64 were included in the analysis. Information on refraining from going out was ascertained by a self-administered questionnaire. The outcome variable, subjective weight gain, was categorized as “increased” or “same as before/reduced” based on the question of subjective weight change in the last month compared to before January 2020. Longitudinal: In addition to cross-sectional data, data from the February 2019, February 2020, and February 2021 surveys were collated; 4399 individuals participated in all four time points, of which 4337 were included in the analysis after excluding outliers. Two outcome variables were used: 1) weight change of “>0 kg” from February 2020 to February 2021, and 2) weight change of “>0 kg” from February 2020 to February 2021 and subjective weight change of “increased”. Logistic regression analysis was used for analysis, adjusting for sex, age, occupation, hospitalization, breakfast deprivation, and snacking (in the longitudinal, the rate of weight change in the year before baseline was also adjusted). In addition, the indirect effect of snacking was examined using the Sobel test.

Results: Cross-sectional: 5168 (28.5%) of 18116 subjects reported weight gain. Multivariate-adjusted odds ratios (95% confidence intervals) for weight gain in comparison with “never refrained” were 1.46 (1.16-1.83) for “almost never refrained,” 1.87 (1.54-2.27) for “sometimes refrained,” and 2.07 (1.71-2.51) for “always refrained” (p-trend <0.001). Snacking had a significant indirect effect on the association between refraining from going out and weight gain (p<0.001). Longitudinal 1) No significant association was found (p-trend =0.401). Longitudinal 2) Similar to the cross-sectional, we found a significant association (p-trend =0.003) and a significant indirect effect of snacking (p<0.001).

Conclusions: Our results implied that refraining from going out after the spread of COVID-19 infection contributed to weight gain, and snacking mediated this association.

Every year, the National Institute of Public Health (NIPH) conducts “Pharmaceutical Hygiene Management Training” as training course for pharmaceutical inspectors belonging to 47 prefectures and PMDA to carry out GMP inspections. In this training, which is held every year for 5 weeks, in addition to the classroom training, mock inspections are conducted with the cooperation of the pharmaceutical plants. In the fiscal year 2021, we gathered online in May 2021 for classroom lectures (3 weeks), preparations for mock inspections and on-site inspections (1 week), and then compiled the report. At that time, we examined whether online inspection could be done. With the cooperation of the pharmaceutical plants, an online inspection was also conducted in hybrid style among three training teams.

As a result of conducting a hybrid style mock inspection exercise with 5 participants in the field and 7 participants online, we convinced the possibility of online inspection as an efficient inspection method by making improvements, although there are various restrictions.

We hope that this experience will lead to the possibility of online inspections in the future, and we report this time.