TY - JOUR
T1 - Synthesizing data and models for the spread of MERS-CoV, 2013
T2 - Key role of index cases and hospital transmission
AU - Chowell, Gerardo
AU - Blumberg, Seth
AU - Simonsen, Lone
AU - Miller, Mark A.
AU - Viboud, Cécile
N1 - Funding Information:
This research was conducted in the context of the Multinational Influenza Seasonal Mortality Study (MISMS), an on-going international collaborative effort to understand influenza epidemiological and evolutionary patterns, led by the Fogarty International Center, National Institutes of Health ( http://www.origem.info/misms/index.php ). Funding for this project comes in part (LS) from the RAPIDD program of the Science & Technology Directorate, Department of Homeland Security, and from the Office of Global Affairs’ International Influenza Unit in the Office of the Secretary of the Department of Health and Human Services . SB acknowledges financial support from RAPIDD program of the Science and Technology Directorate, Department of Homeland Security, the Fogarty International Center , National Institutes of Health , and the National Institute of Health MIDAS program (Modeling Infectious Disease Agent Study, grant number NIH NIGMS 1-U01-GM08778 ].
Publisher Copyright:
© 2014.
PY - 2014
Y1 - 2014
N2 - The outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) has caused 209 deaths and 699 laboratory-confirmed cases in the Arabian Peninsula as of June 11, 2014. Preparedness efforts are hampered by considerable uncertainty about the nature and intensity of human-to-human transmission, with previous reproduction number estimates ranging from 0.4 to 1.5. Here we synthesize epidemiological data and transmission models for the MERS-CoV outbreak during April-October 2013 to resolve uncertainties in epidemic risk, while considering the impact of observation bias. We match the progression of MERS-CoV cases in 2013 to a dynamic transmission model that incorporates community and hospital compartments, and distinguishes transmission by zoonotic (index) cases and secondary cases. When observation bias is assumed to account for the fact that all reported zoonotic cases are severe, but only ~57% of secondary cases are symptomatic, the average reproduction number of MERS-CoV is estimated to be 0.45 (95% CI:0.29-0.61). Alternatively, if these epidemiological observations are taken at face value, index cases are estimated to transmit substantially more effectively than secondary cases, (Ri=0.84 (0.58-1.20) vs Rs=0.36 (0.24-0.51)). In both scenarios the relative contribution of hospital-based transmission is over four times higher than that of community transmission, indicating that disease control should be focused on hospitalized patients.Adjusting previously published estimates for observation bias confirms a strong support for the average R<. 1 in the first stage of the outbreak in 2013 and thus, transmissibility of secondary cases of MERS-CoV remained well below the epidemic threshold. More information on the observation process is needed to clarify whether MERS-CoV is intrinsically weakly transmissible between people or whether existing control measures have contributed meaningfully to reducing the transmissibility of secondary cases. Our results could help evaluate the progression of MERS-CoV in recent months in response to changes in disease surveillance, control interventions, or viral adaptation.
AB - The outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) has caused 209 deaths and 699 laboratory-confirmed cases in the Arabian Peninsula as of June 11, 2014. Preparedness efforts are hampered by considerable uncertainty about the nature and intensity of human-to-human transmission, with previous reproduction number estimates ranging from 0.4 to 1.5. Here we synthesize epidemiological data and transmission models for the MERS-CoV outbreak during April-October 2013 to resolve uncertainties in epidemic risk, while considering the impact of observation bias. We match the progression of MERS-CoV cases in 2013 to a dynamic transmission model that incorporates community and hospital compartments, and distinguishes transmission by zoonotic (index) cases and secondary cases. When observation bias is assumed to account for the fact that all reported zoonotic cases are severe, but only ~57% of secondary cases are symptomatic, the average reproduction number of MERS-CoV is estimated to be 0.45 (95% CI:0.29-0.61). Alternatively, if these epidemiological observations are taken at face value, index cases are estimated to transmit substantially more effectively than secondary cases, (Ri=0.84 (0.58-1.20) vs Rs=0.36 (0.24-0.51)). In both scenarios the relative contribution of hospital-based transmission is over four times higher than that of community transmission, indicating that disease control should be focused on hospitalized patients.Adjusting previously published estimates for observation bias confirms a strong support for the average R<. 1 in the first stage of the outbreak in 2013 and thus, transmissibility of secondary cases of MERS-CoV remained well below the epidemic threshold. More information on the observation process is needed to clarify whether MERS-CoV is intrinsically weakly transmissible between people or whether existing control measures have contributed meaningfully to reducing the transmissibility of secondary cases. Our results could help evaluate the progression of MERS-CoV in recent months in response to changes in disease surveillance, control interventions, or viral adaptation.
KW - Community
KW - Epidemic modeling
KW - Hospital
KW - Index cases
KW - Middle east respiratory syndrome
KW - Reproduction number
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U2 - 10.1016/j.epidem.2014.09.011
DO - 10.1016/j.epidem.2014.09.011
M3 - Article
AN - SCOPUS:84908692878
SN - 1755-4365
VL - 9
SP - 40
EP - 51
JO - Epidemics
JF - Epidemics
ER -