(COVID-19) and the Persistent Threat of Respiratory Tract Infectious Diseases to Global Health Security
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CE: Namrta; MCP/260315; Total nos of Pages: 4; MCP 260315 EDITORIAL CURRENT OPINION The explosive epidemic outbreak of novel coronavirus disease 2019 (COVID-19) and the persistent threat of respiratory tract infectious diseases to global health security Alimuddin Zumlaa,b and Michael S. Niedermanc Respiratory tract infections remain the top cause of considerable consternation and panic among the morbidity and mortality from infectious diseases national, regional, and international public and worldwide [1]. The emergence of new pathogens political communities compounded by news media that cause lethal human respiratory illnesses with and social media hype [12]. A specific molecular test pandemic potential [2,3] pose major challenges and for SARS-CoV-2 was developed [13] and a flurry of rapidly focus the attention of global public health investigations and research on COVID-19 outbreak authorities and HCWs. Two zoonotic coronaviruses rapidly defined the epidemiological, virologic, and which cause lethal respiratory tract infections clinical features and provided evidence of human- in humans feature on the WHO Blueprint list of to-human transmission in community, household, priority pathogens for research and development [4] and hospital settings [6,8–10,14–19]. These have because of their pandemic potential. The first guided the development of numerous WHO guide- human case of severe acute respiratory syndrome lines and recommendation documents related (SARS) coronavirus (SARS-CoV) infection which was to case definitions, reporting of cases, diagnosis, first reported from Guangdong province China [5], management, prevention, and control guideline and that of Middle East respiratory syndrome documents [10]. The rapid spread occurring within (MERS) coronavirus (MERS-CoV) from Jeddah, Saudi China despite a ‘lock down’ of Wuhan resulted in Arabia, in 2012 [5]. In January 2020, another novel numerous chains of transmission [6,10,14–19], and zoonotic coronavirus that causes lethal human spread of the virus was facilitated by national and disease, SARS-CoV-2, was included on the WHO international travel during the January New priority Blueprint list [4]. This followed the appear- Year holiday period [20]. The appearance of novel ance in December 2019 of a case cluster of patients zoonotic diseases is never without controversies with pneumonia of unknown origin in Wuhan, [21–23]. Reports of conspiracy theories for the capital of Hubei province in China [6–8]. The source and sudden appearance of the virus have Chinese Center for Disease Control and Prevention been negated by phylogenetic studies using sequen- (China CDC) epidemiological investigations impli- ces of SARS-CoV2–19 obtained from early cases cated the source as Wuhan’s Huanan Seafood [8,9], which indicate that the novel virus may have Wholesale Market [6]. The China CDC took prompt been introduced to human populations from the action instituting public health measures including animal kingdom in November 2019 or December intensive surveillance, epidemiological investiga- tions, and closure of the market on 1 January 2020. A novel coronavirus was identified from aDivision of Infection and Immunity, Centre for Clinical Microbiology, patients’ samples using whole-genome sequencing University College London, bNIHR Biomedical Research Centre, UCL [8,9] and was provisionally named 2019-nCoV, now Hospitals NHS Foundation Trust, London, UK and cDivision of Pulmonary renamed as SARS-CoV-2 [10]. The disease caused by and Critical Care Medicine, Weill Cornell Medical College, New York, New York, USA SARS-CoV-2 is abbreviated as COVID-19 (COrona- VIrus Disease-2019). Correspondence to: Sir Prof Alimuddin Zumla, MD, PhD, FRCP, Division of Infection and Immunity, Centre for Clinical Microbiology, University The World Health Organization International College London Royal Free Campus, 2nd floor, Rowland Hill Street, Health Regulations Emergency Committee declared London NW3 2PF, United Kingdom. Tel: +44 2074726402; COVID-19 outbreak a Global emergency [11] fax: +44 2077940433; e-mail: [email protected]. because SARS-CoV has spread rapidly within and Curr Opin Pulm Med 2020, 26:000–000 outside China at an alarming pace and has caused DOI:10.1097/MCP.0000000000000676 1070-5287 Copyright ß 2020 Wolters Kluwer Health, Inc. All rights reserved. www.co-pulmonarymedicine.com CE: Namrta; MCP/260315; Total nos of Pages: 4; MCP 260315 Infectious diseases 2019 [21]. As with SARS-CoV [24] and MERS-CoV southern China in 2003 and infected more than [25], defining the actual zoonotic source and mode 3000 people, killing 774 by 2004 before it ended. of primary transmission of SARS-CoV-2 to humans For the COVID-19 outbreak, the China CDC remains an enigma, and requires urgent study recently reported epidemiological features of 44 through ONE-HEALTH collaborations [23]. 672 COVID-19 cases across all of China [6], which The clinical and virologic features of SARS-CoV- showed the overall death rate at 2.3%. In China’s 2 have been defined by several studies [6,10,14–19], provinces, the death rate is 2.9% compared with and although there are similarities to SARS-CoV and 0.4% in the rest of the country. At least 80% of MERS-CoV, some differences have also been the cases have been mild, with the sick and elderly observed. COVID-19 appears to replicate efficiently most at risk. Worryingly 3019 HCWs have been in the upper respiratory tract [14,26] and appears to identified with COVID-19. cause less abrupt onset of symptoms, which are The WHO has established a global surveillance similar to conventional human coronaviruses that system to collect information to describe and moni- are a major cause of common colds and URTIs in the tor COVID-19. Case classifications are based on WHO winter seasons. Furthermore, during the prodrome case definitions for COVID-19 [28]. Active surveil- and early phase of disease, the upper respiratory lance is taking place globally for possible infections tract appears to have large quantity of virus and in all countries using the WHO-recommended may be responsible for the rapid person to person surveillance case definitions. Since its first discovery spread [26]. In SARS-CoV and MERS-CoV, whereas in December 2019, the COVID-19 epidemic has accurate data are unavailable, the highest viral loads progressed relentlessly and there are no indications were seen in seriously ill patients. This has implica- that the epidemic is slowing down [6,29]. As of March tions on infection control measures. COVID-19 also 3, 2020, there were 88948 confirmed cases of COVID- has affinity for cells in the entire respiratory tract. 19 reported to the WHO [28]. Of these, 80174 were The time from exposure to onset of symptoms from China with 2915 deaths; and 8774 cases from is between 2 and 14 days. As with SARS and MERS, 64 countries outside China with 128 deaths. Contin- data for COVID-19 available to date [14–19] indicate ued intensive source control is ongoing at the epi- a spectrum of clinical manifestations occur, from center in China with contact tracing and strict asymptotic subclinical infection, or mild upper infection prevention and control measures being respiratory tract illness to nonlife-threatening pneu- implemented at hospitals, healthcare centers and monia to severe pneumonia progressing to acute quarantine facilities. respiratory distress syndrome (ARDS) requiring With ease of travel, the world has become increas- intensive care, mechanical ventilation, and extra- ingly susceptible to outbreaks of new and reemerging corporeal membrane oxygenation (ECMO). A study infectious diseases that can spread quickly because of of 138 hospitalized patients with COVID-19 ease of transportation and rapid movement of people the median age was 56 years (interquartile range, within regions and continents. The virus has spread 42–68; range, 22–92 years) and 75 (54.3%) were beyond mainland China to countries around the men. Several studies [14–19] show that symptoms globe and two cruise ships are now confirmed to of COVID-19 patients are similar to MERS and have been affected. WHO has recommended that SARS and fever (92–98%), dry cough (75–82%), countries with frequent air travel exchange with fatigue (69–75%), and gastrointestinal symptoms Wuhan should take precautionary public health (20–40%) were the most common clinical manifes- measures and undertake screening and infection tations. A wide spectrum of clinical disease is being control activities. The lock-down of Wuhan City seen from asymptomatic, subclinical, mild, and self- seems to have slowed international spread of limiting disease to severe disease and ARDS among COVID-19 but many challenges remain before it older people or those with other comorbid diseases can be brought under control [30]. such as diabetes, chronic respiratory disease, and A recent Conference (11th and 12th February hypertension, with men are more likely to die than 2020) held in Geneva hosted by WHO in Geneva women. Several of these patients have negative [31] delineated priorities for intensified research for rtPCR tests. Bilateral ground glass or patchy opacity development of point of care diagnostic tests, new are the most common signs of radiological finding vaccines, treatments, improved collaborations with and CT changes [27] have been included as a case the animal and environmental sectors, and commu- definition of COVID-19 by China CDC. nity engagement. Although the world awaits the Although COVID-19 appears from currently development and evaluation of new vaccines, available data to have a lower death rate [6], it has anti-SARS-CoV-2 specific drugs, antibody, and/or caused more deaths than SARS and MERS combined. other host-directed interventions [32,33], public The SARS outbreak in 2003 had rapidly spread from health infection control measures remain of prime 2 www.co-pulmonarymedicine.com Volume 26 Number 00 Month 2020 CE: Namrta; MCP/260315; Total nos of Pages: 4; MCP 260315 Epidemic outbreak of novel SARS-CoV-2 Zumla and Niederman importance in limiting human-to-human transmis- and prevention of community acquired pneumonia, sion, especially among close contacts and HCWs, and bacterial and viral RTIs [34–42].