Closed environments facilitate secondary transmission of coronavirus disease 2019 (COVID-19)

ObjectiveTo identify common features of cases with novel coronavirus disease (COVID-19) so as to better understand what factors promote secondary transmission including superspreading events. MethodsA total of 110 cases were examined among eleven clusters and sporadic cases, and investigated who acquired infection from whom. The clusters included four in Tokyo and one each in Aichi, Fukuoka, Hokkaido, Ishikawa, Kanagawa and Wakayama prefectures. The number of secondary cases generated by each primary case was calculated using contact tracing data. ResultsOf the 110 cases examined, 27 (24.6%) were primary cases who generated secondary cases. The odds that a primary case transmitted COVID-19 in a closed environment was 18.7 times greater compared to an open-air environment (95% confidence interval [CI]: 6.0, 57.9). ConclusionsIt is plausible that closed environments contribute to secondary transmission of COVID-19 and promote superspreading events. Our findings are also consistent with the declining incidence of COVID-19 cases in China, as gathering in closed environments was prohibited in the wake of the rapid spread of the disease.

Lessons Learned from International Responses to Severe Acute Respiratory Syndrome (SARS)

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.

Lessons learned from international responses to severe acute respiratory syndrome (SARS)

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.