p_sym_if_inf 
A twoelement numeric vector containing c(alpha,
beta) parameters/hyperpriors of a Beta distribution modeling the
probability of becoming symptomatic if infectious.
Sources for default value:
Byambasuren O, Cardona M, Bell K, Clark J, McLaws M, Glasziou P (2020).
“Estimating the extent of asymptomatic COVID19 and its potential for community transmission: systematic review and metaanalysis.”
Infectious Diseases (except HIV/AIDS).
doi: 10.1101/2020.05.10.20097543
, http://medrxiv.org/lookup/doi/10.1101/2020.05.10.20097543.
Mizumoto K, Kagaya K, Zarebski A, Chowell G (2020).
“Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2020.”
Eurosurveillance, 25(10).
ISSN 15607917, doi: 10.2807/15607917.ES.2020.25.10.2000180
, https://www.eurosurveillance.org/content/10.2807/15607917.ES.2020.25.10.2000180.
Nishiura H, Kobayashi T, Miyama T, Suzuki A, Jung S, Hayashi K, Kinoshita R, Yang Y, Yuan B, Akhmetzhanov AR, Linton NM (2020).
“Estimation of the asymptomatic ratio of novel coronavirus infections (COVID19).”
International Journal of Infectious Diseases, 94, 154155.
ISSN 12019712, doi: 10.1016/j.ijid.2020.03.020
, https://linkinghub.elsevier.com/retrieve/pii/S1201971220301399.

p_sev_if_sym 
A twoelement numeric vector containing c(alpha,
beta) parameters/hyperpriors of a Beta distribution modeling the
probability of transitioning into the "severe" health state if
symptomatic. "Severe" disease is defined as disease that would likely
require hospitalization.
Sources for default value:
CDC COVID19 Response Team, CDC COVID19 Response Team, Bialek S, Boundy E, Bowen V, Chow N, Cohn A, Dowling N, Ellington S, Gierke R, Hall A, MacNeil J, Patel P, Peacock G, Pilishvili T, Razzaghi H, Reed N, Ritchey M, SauberSchatz E (2020).
“Severe Outcomes Among Patients with Coronavirus Disease 2019 (COVID19) — United States, February 12–March 16, 2020.”
MMWR. Morbidity and Mortality Weekly Report, 69(12), 343346.
ISSN 01492195, 1545861X, doi: 10.15585/mmwr.mm6912e2
, http://www.cdc.gov/mmwr/volumes/69/wr/mm6912e2.htm?s_cid=mm6912e2_w.
Verity R, Okell LC, Dorigatti I, Winskill P, Whittaker C, Imai N, CuomoDannenburg G, Thompson H, Walker PGT, Fu H, Dighe A, Griffin JT, Baguelin M, Bhatia S, Boonyasiri A, Cori A, Cucunubá Z, FitzJohn R, Gaythorpe K, Green W, Hamlet A, Hinsley W, Laydon D, NedjatiGilani G, Riley S, van Elsland S, Volz E, Wang H, Wang Y, Xi X, Donnelly CA, Ghani AC, Ferguson NM (2020).
“Estimates of the severity of coronavirus disease 2019: a modelbased analysis.”
The Lancet Infectious Diseases, 20(6), 669677.
ISSN 14733099, doi: 10.1016/S14733099(20)302437
, https://linkinghub.elsevier.com/retrieve/pii/S1473309920302437.

p_die_if_sev 
A twoelement numeric vector containing c(alpha,
beta) parameters/hyperpriors of a Beta distribution modeling the
probability of dying if in the "severe" health state.
Source for default value: CDC COVID19 Response Team, CDC COVID19 Response Team, Bialek S, Boundy E, Bowen V, Chow N, Cohn A, Dowling N, Ellington S, Gierke R, Hall A, MacNeil J, Patel P, Peacock G, Pilishvili T, Razzaghi H, Reed N, Ritchey M, SauberSchatz E (2020).
“Severe Outcomes Among Patients with Coronavirus Disease 2019 (COVID19) — United States, February 12–March 16, 2020.”
MMWR. Morbidity and Mortality Weekly Report, 69(12), 343346.
ISSN 01492195, 1545861X, doi: 10.15585/mmwr.mm6912e2
, http://www.cdc.gov/mmwr/volumes/69/wr/mm6912e2.htm?s_cid=mm6912e2_w. 
p_die_if_inf 
A twoelement numeric vector containing c(alpha,
beta) parameters/hyperpriors of a Beta distribution modeling the
probability of dying if infected (e.g. the infection fatality rate). This
prior represents a national average value, which is later adjusted for
state and countylevel factors, and to reflect higher fatality rates early
in the epidemic.
Source for default value: Adummy A (2021).
“Not avalable.”
Failed to insert reference with key = ODriscoll_Nature_2020 from package = 'covidestim'. Possible cause  missing or misspelled key. 
ifr_decl_OR 
A twoelement numeric vector containing c(shape,
rate) parameters/hyperpriors of a Gamma distribution modeling the
elevated IFR in early 2020, relative to the present. Default value
represents an IFR 30% higher in March of 2020, with 95% interval 1050%
higher.
Source for default value: Expert opinion 