COVID-19 Pandemic Planning Scenarios|CDC

. The lower bound price quote is the lowest, non-zero point estimate throughout the 6 areas, while the upper bound is the acme quote throughout the 6 areas. § The percent of cases that are asymptomatic, i.e. never ever experience symptoms, stays unsure. Longitudinal testing of individuals is needed to precisely detect the absence of symptoms for the complete period of infectiousness . Existing peer-reviewed and preprint research studies differ widely in follow-up times for re-testing, or do not include re-testing of cases. In addition, studies vary in the definition of a symptomatic case, which makes it difficult to make direct contrasts between price quotes. The percent of cases that are asymptomatic may differ by age, and the age groups reported in studies differ. Provided these restrictions, the range of estimates for Scenarios 1-4 is large. The lower bound estimate approximates the lower 95%self-confidence period bound approximated from: Byambasuren, O., Cardona, M., Bell, K., Clark, J., McLaws, M. L., & Glasziou, P.(2020). Estimating the level of real asymptomatic COVID-19 and its potential for community transmission: methodical evaluation and meta-analysis. Available at SSRN 3586675. The upper bound quote approximates the upper 95 %self-confidence interval bound approximated from: Poletti, P., Tirani, M., Cereda, D., Trentini, F., Guzzetta, G., Sabatino, G., Marziano, V., Castrofino, A., Grosso, F., Del Castillo, G. and Piccarreta, R.( 2020). Likelihood of symptoms and important disease after SARS-CoV-2 infection. arXiv preprint arXiv:2006.08471. The best price quote is the midpoint of this variety

and aligns with price quotes from: Oran DP, Topol EJ. Prevalence of Asymptomatic SARS-CoV-2 Infection: A Narrative Review [released online ahead of print, 2020 Jun 3] Ann Intern Med. 2020; M20-3012. ¶ The current best estimate is based on numerous presumptions. The relative infectiousness of asymptomatic cases to symptomatic cases stays highly uncertain, as asymptomatic cases are tough to recognize, and transmission is difficult to measure and observe. The quotes for relative infectiousness are presumptions based upon studies of viral shedding characteristics. The upper bound of this quote reflects research studies that have shown similar durations and quantities of viral shedding in between asymptomatic and symptomatic cases: Lee, S., Kim, T., Lee, E., Lee, C., Kim, H., Rhee, H., Park, S.Y., Son, H.J., Yu, S., Park, J.W. and Choo, E.J., Clinical Course and Molecular Viral Shedding Among Asymptomatic and Symptomatic Patients With SARS-CoV-2 Infection in a Community Treatment Center in the Republic of Korea. JAMA Internal Medicine; Zou L, Ruan F, Huang M, et al. SARS-CoV-2 Viral Load in Upper Respiratory Specimens of Infected Patients. N Engl J Med. 2020; 382(12):1177 -1179; and Zhou R, Li F, Chen F, et al. Viral characteristics in asymptomatic patients with COVID-19. Int J Infect Dis. 2020; 96:288 -290. The lower bound of this quote shows information showing that viral loads are higher in serious cases relative to mild cases (Liu Y, Yan LM, Wan L, et al. Viral dynamics in severe and moderate cases of COVID-19. Lancet Infect Dis. 2020; 20(6 ):656 -657 )and data showing that viral loads and shedding durations are higher among symptomatic cases relative to asymptomatic cases( Noh JY, Yoon JG, Seong H, et al. Asymptomatic infection and irregular manifestations of

COVID-19: Comparison of viral shedding period [released online ahead of print, 2020 May 21] J Infect. 2020; S0163-4453(20 )30310-8). ** The lower bound of this criterion is estimated from the lower 95%confidence period bound from: He, X., Lau, E.H., Wu, P., Deng, X., Wang, J., Hao, X., Lau, Y.C., Wong, J.Y., Guan, Y., Tan, X. and Mo, X. (2020 ). Temporal characteristics in viral shedding and transmissibility of COVID-19. Nature medication, 26(5 ), pp.672-675. The upper bound of this parameter is approximated from the greater quotes of specific research studies consisted of in: Casey, M., Griffin, J., McAloon, C.G., Byrne, A.W., Madden, J.M., McEvoy, D., Collins, A.B., Hunt, K., Barber, A., Butler, F. and Lane, E.A.(2020). Estimating pre-symptomatic transmission of COVID-19: a secondary analysis using published information. medRxiv.The finest estimate is the geometric mean of the point estimates from these 2 research studies. Table 2. Specification Values Common to the Five COVID-19 Pandemic Planning Scenarios. The criterion values are likely to change as we get extra information about disease seriousness and viral transmissibility of COVID-19. Specification values are based upon information received by CDC through August 8, 2020, including COVID-19 Case Surveillance Public Use Data (https://data.cdc.gov/Case-Surveillance/COVID-19-Case-Surveillance-Public-Use-Data/vbim-akqf ); information from the Hospitalization Surveillance Network (COVID-NET)(through August 1 ); and data from Data Collation and Integration for Public Health Event Response(DCIPHER ). Parameter worths Table 2 Pre-existing immunity Presumption, ASPR and CDC No pre-existing immunity before the pandemic began in 2019. It is assumed that all members of the U.S. population were susceptible to infection prior to the pandemic. Time from exposure to sign onset * ~ 6 days(mean )Time from sign start in a private and sign start of a second person infected by that specific † ~ 6 days (mean )Mean ratio of approximated infections to reported case counts, Overall(range)§ 11(6, 24 )Parameter Values Related to Healthcare Usage Typical variety of days from symptom onset to SARS-CoV-2 test amongst SARS-CoV-2 positive clients(interquartile range )¶ Overall: 3 (1, 6)days Median number of days from symptom beginning to hospitalization(interquartile range) ** 18-49 years: 6( 3, 10)days 50-64 years: 6(2, 10)days ≥ 65 years: 4(1, 9)days Median variety of days of hospitalization amongst those not admitted to ICU(interquartile variety)† † 18-49 years: 3 (2, 5)days 50-64 years: 4(2, 7)days ≥ 65 years: 6(3, 10)days Typical number of days of hospitalization among those confessed to ICU (interquartile range)† †, §

§ 18-49 years: 11(6, 20)days 50-64 years: 14(8, 25 )days ≥ 65 years: 12(6, 20) days Percent confessed to ICU among those hospitalized † † 18-49 years: 23.8% 50-64 years: 36.1%≥ 65 years: 35.3 %Percent on mechanical ventilation amongst those hospitalized.

Consists of both non-ICU and ICU admissions † † 18-49 years: 12.0% 50-64 years: 22.1 %≥ 65 years: 21.1%Percent that pass away among those hospitalized. Consists of both non-ICU and ICU admissions † † 18-49 years: 2.4%50-64 years: 10.0%≥ 65 years: 26.6%Median number of days of mechanical ventilation (interquartile range)** Overall: 6(2, 12)days Mean variety of days from sign beginning to death (interquartile range

, inclusive of

both ICU and non-ICU days

. ¶ ¶ Estimates just include death

dates between March 1, 2020

— July 15, 2020 to ensure

enough time for reporting. Information for 17 year olds and under are suppressed due to small sample

sizes. This material was initially released here.

† These estimates are based on age-specific quotes of infection death ratios from Hauser, A., Counotte, M.J., Margossian, C.C., Konstantinoudis, G., Low, N., Althaus, C.L. and Riou, J., 2020. Hauser et al. produced price quotes of IFR for 10-year age bands from 0 to 80+year old for 6 regions in Europe. The quotes for persons ≥ 70 years old provided here do not consist of persons ≥ 80 years old as IFR estimates from Hauser et al., assumed that 100%of infections among individuals ≥ 80 years old were reported. The lower bound quote is the lowest, non-zero point price quote throughout the 6 areas, while the upper bound is the greatest point price quote across the 6 areas. The upper bound price quote approximates the upper 95 %self-confidence period bound estimated from: Poletti, P., Tirani, M., Cereda, D., Trentini, F., Guzzetta, G., Sabatino, G., Marziano, V., Castrofino, A., Grosso, F., Del Castillo, G. and Piccarreta, R.( 2020).