Estimating the reproductive number R0 of SARS-CoV-2 in the United States and eight European countries and implications for vaccination.
J Theor Biol
; 517: 110621, 2021 05 21.
Article
in English
| MEDLINE | ID: covidwho-1114510
ABSTRACT
SARS-CoV-2 rapidly spread from a regional outbreak to a global pandemic in just a few months. Global research efforts have focused on developing effective vaccines against COVID-19. However, some of the basic epidemiological parameters, such as the exponential epidemic growth rate and the basic reproductive number, R0, across geographic areas are still not well quantified. Here, we developed and fit a mathematical model to case and death count data collected from the United States and eight European countries during the early epidemic period before broad control measures were implemented. Results show that the early epidemic grew exponentially at rates between 0.18 and 0.29/day (epidemic doubling times between 2.4 and 3.9 days). We found that for such rapid epidemic growth, high levels of intervention efforts are necessary, no matter the goal is mitigation or containment. We discuss the current estimates of the mean serial interval, and argue that existing evidence suggests that the interval is between 6 and 8 days in the absence of active isolation efforts. Using parameters consistent with this range, we estimated the median R0 value to be 5.8 (confidence interval 4.7-7.3) in the United States and between 3.6 and 6.1 in the eight European countries. We further analyze how vaccination schedules depend on R0, the duration of protective immunity to SARS-CoV-2, and show that individual-level heterogeneity in vaccine induced immunity can significantly affect vaccination schedules.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Vaccination
/
COVID-19 Vaccines
/
SARS-CoV-2
/
COVID-19
/
Models, Biological
Type of study:
Observational study
Topics:
Vaccines
Limits:
Female
/
Humans
/
Male
Country/Region as subject:
North America
/
Europa
Language:
English
Journal:
J Theor Biol
Year:
2021
Document Type:
Article
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