Influenza is one of most common acute viral infections in humans. It is estimated that seasonal epidemics affect 10–20% of the population, resulting in 250 000 to 500 000 deaths every year. In addition to seasonal influenza epidemics, antigenically distinct viruses originated from animal species tend to emerge in the human population every 10 to 40 years. Since most the human population does not have immunity to such viruses, global epidemics with significant impact, i.e. influenza pandemics, have occurred in the past.

It is critical to monitor the incidence and clinical characteristics of influenza and its associated hospitalization to understand influenza disease burden. A disease burden study can inform the prioritization of a public health response. However, little is known about the epidemiology and disease burden of influenza in developing countries, including Mongolia. Thus we performed prospective data and sample collection from patients who visited outpatient clinics with influenza-like illness (ILI) and hospitalized patients with severe acute respiratory infections (SARI) in two sites of Mongolia, Baganuur District of Ulaanbaatar and Selenghe Province, from 2008 to 2010. In total, we examined 350 ILI cases during the 2008–2009 influenza epidemic period and 1723 ILI cases during the 2009–2010 influenza epidemic period. We observed the highest ILI incidence per 1000 population in the one to four year age group in Baganuur and in the under one year age group in Selenghe during both periods. Thirteen SARI cases were positive for seasonal influenza A(H1N1) during the 2008–2009 season and 17 SARI cases were positive for pandemic influenza A(H1N1) 2009 during the 2009–2010 season. Among these cases, 84.6% and 58.8% were children under five years of age, respectively, during the 2008–2009 and 2009–2010 seasons. Taken together, children, especially children under five years, had higher influenza infection incidence and hospitalization rate in Mongolia. Although mortality impact also should be considered, we believe that our findings can be useful in formulating an influenza control strategy during influenza epidemic periods in Mongolia.

In early February 2003, a previously unknown disease causing severe pneumonia was recognised. This disease which is now known as severe acute respiratory syndrome (SARS) is believed to have had its origins in the Guangdong Province of China, and was the cause of a multi-country epidemic resulting in significant morbidity and mortality. The World Health Organization (WHO) has been coordinating the international response to provide the epidemiological, laboratory, clinical and logistic requirements needed to contain this disease.A rapid spread of SARS around the world occurred at its onset, facilitated greatly by air travel. Between November 2002 and July 2003, a total of 8,094 cases and 774 cases were reported from 26 countries worldwide.WHO responded quickly to this multi-country outbreak and on 12 March released a "global alert" about SARS. This was followed by the first WHO travel advisory on 15 March. The Global Outbreak Alert and Response Network was activated, and international experts were brought together to implement enhanced global surveillance systems for SARS.The international community has learned a lot of lessons from the SARS outbreak. Particularly, rapid and transparent information sharing between countries is critical to prevent international spread of the disease. However, information exchange was less than optimal in the early phase of the outbreak.

In response to the outbreak of coronavirus disease 2019 (COVID-19) in Japan, a national COVID-19 cluster taskforce (comprising governmental and nongovernmental experts) was established to support the country’s Ministry of Health, Labour and Welfare in conducting daily risk assessment. The assessment was carried out using established infectious disease surveillance systems; however, in the initial stages of the pandemic these were not sufficient for real-time risk assessment owing to limited accessibility, delay in data entry and inadequate case information. Also, local governments were publishing anonymized data on confirmed COVID-19 cases on their official websites as daily press releases. We developed a unique database for nationwide real-time risk assessment that included these case lists from local government websites and integrated all case data into a standardized format. The database was updated daily and checked systematically to ensure comprehensiveness and quality. Between 15 January 2020 and 15 June 2021, 776 459 cases were logged in the database, allowing for analysis of real-time risk from the pandemic. This semi-automated database was used in daily risk assessments, and to evaluate and update control measures to prevent community transmission of COVID-19 in Japan. The data were reported almost every week to the Japanese Government Advisory Panel on COVID-19 for public health responses.