Background: Describing transmission dynamics of the outbreak and impact of
intervention measures are critical to planning responses to future
outbreaks and providing timely information to guide policy makers
decision. We estimate serial interval (SI) and temporal reproduction
number (Rt) of SARS-CoV-2 in Tunisia. Methods: We collected data of
investigations and contact tracing between March 1, 2020 and May 5, 2020
as well as illness onset data during the period February 29-May 5, 2020
from National Observatory of New and Emerging Diseases of Tunisia. Maximum
likelihood (ML) approach is used to estimate dynamics of Rt. Results: 491
of infector-infectee pairs were involved, with 14.46% reported
pre-symptomatic transmission. SI follows Gamma distribution with mean 5.30
days [95% CI 4.66-5.95] and standard deviation 0.26 [95% CI 0.23-0.30].
Also, we estimated large changes in Rt in response to the combined
lockdown interventions. The Rt moves from 3.18 [95% CI 2.73-3.69] to 1.77
[95% CI 1.49-2.08] with curfew prevention measure, and under the epidemic
threshold (0.89 [95% CI 0.84-0.94]) by national lockdown measure.
Conclusions: Overall, our findings highlight contribution of interventions
to interrupt transmission of SARS-CoV-2 in Tunisia. Data is obtained from contact tracing between March 1 and May 5,
2020 from the National Observatory of New and Emerging Diseases of Tunis,
Tunisia. It was screened to clearly identified transmission events, which
are a known pairs of index and secondary cases and the dates of symptom
onset for both cases. This metadata includes two datasets: the first one consists of
contact tracing including information for pairs, dates of symptoms onset
for both infector and infectee as well as the ID for them, the second one
consists of a daily time series including information for dates and number
of incident cases.