Epidemiology - Revision history

Bosmana: /* Children */

2020-09-18T20:08:15Z

‎Children

Bosmana: /* Unusual clinical expression */

2020-07-06T09:14:52Z

‎Unusual clinical expression

Bosmana: /* Consequences for action */

2020-07-02T07:58:32Z

‎Consequences for action

Bosmana: /* Observations */

2020-07-02T07:55:26Z

‎Observations

Bosmana: /* Observations */

2020-07-02T07:54:22Z

‎Observations

Bosmana: /* Analysis and interpretation */

2020-07-02T07:53:55Z

‎Analysis and interpretation

Bosmana: /* Observations */

2020-07-02T07:47:58Z

‎Observations

Bosmana: /* Consequences for action */

2020-04-24T15:37:23Z

‎Consequences for action

Bosmana: /* Unusual clinical expression */

2020-04-24T15:36:01Z

‎Unusual clinical expression

Bosmana at 14:28, 24 April 2020

2020-04-24T14:28:58Z

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 * A large study of 2,143 pediatric patients in China found that, while 90% had mild or moderate illness, children <1 are more likely to have critical illness, if infected. <ref>Dong, Y., Mo, X., Hu, Y., Qi, X., Jiang, F., Jiang, Z., & Tong, S. (2020). Epidemiological characteristics of 2143 pediatric patients with 2019 coronavirus disease in China. Pediatrics.</ref>
 * Overall, children are at a similar risk of '''infection''' as the adult population, though less likely to have severe ''symptoms'', if infected. <ref name="BiQ2020"/> <Ref name="ECDCRRA7"/>
 ===Reservoir and sources===

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 * Some note "chilblains-like lesion or as a vasculitis-like presentation on fingers and toes that can occur in children, teenagers and adults who have been diagnosed as positive for COVID-19 or are asymptomatic." <Ref>COVID-19 Skin Manifestations And The Foot: What We Know So Far. April 22, 2020 By Tracey Vlahovic DPM. https://www.podiatrytoday.com/blogged/covid-19-skin-manifestations-and-foot-what-we-know-so-far</ref>
 * In Italy, health-care practitioners confirmed dozens of reports of acrocyanotic lesions in asymptomatic COVID-19-positive children and adolescents who were generally in good health prior to the skin rash onset. <ref>Mazzotta F, Troccoli T. Acute acro-ischemia in the child at the time of COVID-19. International Federation of Podiatrists. Available at: https://www.fip-ifp.org/wp-content/uploads/2020/04/acroischemia-ENG.pdf Accessed April 16, 2020.</ref>
+* Cardiac arrests and arrhythmias are likely the consequence of systemic illness and not solely the direct effects of COVID-19 infection. <ref>Bhatla, A., Mayer, M. M., Adusumalli, S., Hyman, M. C., Oh, E., Tierney, A., ... & Domenico, C. M. (2020). COVID-19 and Cardiac Arrhythmias. Heart Rhythm.</ref>
 ==Analysis and interpretation==
 * The dermatological signs, if confirmed to be associated to SARS-CoV2, could be useful for identifying children and adolescents with minimal forms of infection, but potential sources of further infection.

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 ==Consequences for action==
-* Ideally, cohorts of exposed individuals need to be identified and followed up to establish the proportion asymptomatic more reliably.
+* More field studies such as the one designed and performed by Valencia and others <ref name="Valencia2020"/> are needed to further strengthen the body of evidence around the natural history of SARS-CoV2 infections. Understanding the extend of asymptomatic transmission is a relevant piece of evidence to be taken into account in response strategies (be it containment or mitigation)
 =Anosmia=

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 =Proportion asymptomatic=
 ==Observations==
-* There is clear evidence of asymptomatic infection with COVID-19. Estimates of the proportion of laboratory-confirmed cases who are asymptomatic may vary by age group, study setting and study methodology ranging from 1.2% (China)<ref>Surveillances, V. (2020). The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19)—China, 2020. China CDC Weekly, 2(8), 113-122.</ref>, 6.4% (Italy)<Ref>[https://www.epicentro.iss.it/coronavirus/bollettino/Infografica_26marzo%20ENG.pdf Integrated surveillance of COVID19 in Italy. Website ISS]</ref>, 12.9% (pediatric cases in China)<ref>Dong, Y., Mo, X., Hu, Y., Qi, X., Jiang, F., Jiang, Z., & Tong, S. (2020). Epidemiological characteristics of 2143 pediatric patients with 2019 coronavirus disease in China. Pediatrics.</ref>, 13.0% (long-term care facility in Washington State) <RefKimball, A. (2020). Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility—King County, Washington, March 2020. MMWR. Morbidity and Mortality Weekly Report, 69.</ref>, and 17.9% (modelled estimate based on data from the Diamond Princess cruise ship)<Ref name=“Mizmuto2020”>Mizumoto, K., Kagaya, K., Zarebski, A., & Chowell, G. (2020). Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2020. [https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2020.25.10.2000180 Eurosurveillance, 25(10).] </ref>. The extent to which screening is undertaken in group exposures and for contacts of cases, as well the duration of follow-up to ensure asymptomatic individuals do not subsequently develop symptoms will also influence the proportion of cases who are asymptomatic. <Ref>[https://www.publichealthontario.ca/-/media/documents/ncov/what-we-know-jan-30-2020.pdf?la=en What We Know So Far About… Asymptomatic Infection and Asymptomatic Transmission.] SYNOPSIS Version 4 03/30/2020 [https://www.publichealthontario.ca/en/diseases-and-conditions/infectious-diseases/respiratory-diseases/novel-coronavirus/what-we-know COVID-19 – Public Health Ontario]</ref>
+* There is clear evidence of asymptomatic infection with COVID-19. Estimates of the proportion of laboratory-confirmed cases who are asymptomatic may vary by age group, study setting and study methodology ranging from 1.2% (China)<ref>Surveillances, V. (2020). The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19)—China, 2020. China CDC Weekly, 2(8), 113-122.</ref>, 6.4% (Italy)<Ref>[https://www.epicentro.iss.it/coronavirus/bollettino/Infografica_26marzo%20ENG.pdf Integrated surveillance of COVID19 in Italy. Website ISS]</ref>, 12.9% (pediatric cases in China)<ref>Dong, Y., Mo, X., Hu, Y., Qi, X., Jiang, F., Jiang, Z., & Tong, S. (2020). Epidemiological characteristics of 2143 pediatric patients with 2019 coronavirus disease in China. Pediatrics.</ref>, 13.0% (long-term care facility in Washington State) <Ref>Kimball, A. (2020). Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility—King County, Washington, March 2020. MMWR. Morbidity and Mortality Weekly Report, 69.</ref>, and 17.9% (modelled estimate based on data from the Diamond Princess cruise ship)<Ref name=“Mizmuto2020”>Mizumoto, K., Kagaya, K., Zarebski, A., & Chowell, G. (2020). Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2020. [https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2020.25.10.2000180 Eurosurveillance, 25(10).] </ref>. The extent to which screening is undertaken in group exposures and for contacts of cases, as well the duration of follow-up to ensure asymptomatic individuals do not subsequently develop symptoms will also influence the proportion of cases who are asymptomatic. <Ref>[https://www.publichealthontario.ca/-/media/documents/ncov/what-we-know-jan-30-2020.pdf?la=en What We Know So Far About… Asymptomatic Infection and Asymptomatic Transmission.] SYNOPSIS Version 4 03/30/2020 [https://www.publichealthontario.ca/en/diseases-and-conditions/infectious-diseases/respiratory-diseases/novel-coronavirus/what-we-know COVID-19 – Public Health Ontario]</ref>
 * A cohort study around an outbreak of COVID19 in a bar in Vietnam in March 2020 suggests that the proportion of asymptomatic infections is larger than estimated so far. The study differentiated between asymptomatic (44% of all observed infections) and presymptomatic (38%).  <ref name="Valencia2020">Valencia C, Quang L, Handcock M, Nguyen D, Doan Q, Nguyen TV, Le N, Truong T, Do H, Otsu S, Le T. Asymptomatic and Presymptomatic Transmission of 2019 Novel Coronavirus (COVID-19) Infection: An Estimation from a Cluster of Confirmed Cases in Ho Chi Minh City, Vietnam.</ref>

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 ==Observations==
 * There is clear evidence of asymptomatic infection with COVID-19. Estimates of the proportion of laboratory-confirmed cases who are asymptomatic may vary by age group, study setting and study methodology ranging from 1.2% (China)<ref>Surveillances, V. (2020). The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19)—China, 2020. China CDC Weekly, 2(8), 113-122.</ref>, 6.4% (Italy)<Ref>[https://www.epicentro.iss.it/coronavirus/bollettino/Infografica_26marzo%20ENG.pdf Integrated surveillance of COVID19 in Italy. Website ISS]</ref>, 12.9% (pediatric cases in China)<ref>Dong, Y., Mo, X., Hu, Y., Qi, X., Jiang, F., Jiang, Z., & Tong, S. (2020). Epidemiological characteristics of 2143 pediatric patients with 2019 coronavirus disease in China. Pediatrics.</ref>, 13.0% (long-term care facility in Washington State) <RefKimball, A. (2020). Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility—King County, Washington, March 2020. MMWR. Morbidity and Mortality Weekly Report, 69.</ref>, and 17.9% (modelled estimate based on data from the Diamond Princess cruise ship)<Ref name=“Mizmuto2020”>Mizumoto, K., Kagaya, K., Zarebski, A., & Chowell, G. (2020). Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2020. [https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2020.25.10.2000180 Eurosurveillance, 25(10).] </ref>. The extent to which screening is undertaken in group exposures and for contacts of cases, as well the duration of follow-up to ensure asymptomatic individuals do not subsequently develop symptoms will also influence the proportion of cases who are asymptomatic. <Ref>[https://www.publichealthontario.ca/-/media/documents/ncov/what-we-know-jan-30-2020.pdf?la=en What We Know So Far About… Asymptomatic Infection and Asymptomatic Transmission.] SYNOPSIS Version 4 03/30/2020 [https://www.publichealthontario.ca/en/diseases-and-conditions/infectious-diseases/respiratory-diseases/novel-coronavirus/what-we-know COVID-19 – Public Health Ontario]</ref>
-* A cohort study around an outbreak of COVID19 in a bar in Vietnam in March 2020 suggests that the proportion of asymptomatic infections is larger than estimated so far. The study differentiated between asymptomatic (44% of all observed infections) and presymptomatic (38%).  <ref>Valencia C, Quang L, Handcock M, Nguyen D, Doan Q, Nguyen TV, Le N, Truong T, Do H, Otsu S, Le T. Asymptomatic and Presymptomatic Transmission of 2019 Novel Coronavirus (COVID-19) Infection: An Estimation from a Cluster of Confirmed Cases in Ho Chi Minh City, Vietnam.</ref>
+* A cohort study around an outbreak of COVID19 in a bar in Vietnam in March 2020 suggests that the proportion of asymptomatic infections is larger than estimated so far. The study differentiated between asymptomatic (44% of all observed infections) and presymptomatic (38%).  <ref name="Valencia2020">Valencia C, Quang L, Handcock M, Nguyen D, Doan Q, Nguyen TV, Le N, Truong T, Do H, Otsu S, Le T. Asymptomatic and Presymptomatic Transmission of 2019 Novel Coronavirus (COVID-19) Infection: An Estimation from a Cluster of Confirmed Cases in Ho Chi Minh City, Vietnam.</ref>
 ==Analysis and interpretation==

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 ==Analysis and interpretation==
-* The observations by Mizumoto and the International WHO Mission seem to contradict on the issue of proportion asymptomatic infections. Though cruise ship populations are hardly representative of national populations, they can be considered reliable environments to study the natural history of infectious disease, when observing large groups of exposed susceptibles.
+* The observations by Mizumoto and the International WHO Mission seemed to contradict on the issue of proportion asymptomatic infections. Though cruise ship populations are hardly representative of national populations, they can be considered reliable environments to study the natural history of infectious disease, when observing large groups of exposed susceptibles.
 * Having reliable estimates of the proportion asymptomatics is relevant for modelling the disease at the population level and making predictions about group immunity and transmission coefficients.

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 ==Consequences for Action==
 * If the relation COVID19 and Anosmia is confirmed, then clusters of sudden anosmia could be considered a clinical indicator of COVID19 in the population when testing is unavailable.
 =References=