Intrinsic generation time of the SARS-CoV-2 Omicron variant: An observational study of household transmission.
Bayesian inference
COVID-19
Contact tracing
Generation time
Omicron
SARS-CoV-2
Journal
The Lancet regional health. Europe
ISSN: 2666-7762
Titre abrégé: Lancet Reg Health Eur
Pays: England
ID NLM: 101777707
Informations de publication
Date de publication:
Aug 2022
Aug 2022
Historique:
entrez:
6
7
2022
pubmed:
7
7
2022
medline:
7
7
2022
Statut:
ppublish
Résumé
Starting from the final months of 2021, the SARS-CoV-2 Omicron variant expanded globally, swiftly replacing Delta, the variant that was dominant at the time. Many uncertainties remain about the epidemiology of Omicron; here, we aim to estimate its generation time. We used a Bayesian approach to analyze 23,122 SARS-CoV-2 infected individuals clustered in 8903 households as determined from contact tracing operations in Reggio Emilia, Italy, throughout January 2022. We estimated the distribution of the intrinsic generation time (the time between the infection dates of an infector and its secondary cases in a fully susceptible population), realized household generation time, realized serial interval (time between symptom onset of an infector and its secondary cases), and contribution of pre-symptomatic transmission. We estimated a mean intrinsic generation time of 6.84 days (95% credible intervals, CrI, 5.72-8.60), and a mean realized household generation time of 3.59 days (95%CrI: 3.55-3.60). The household serial interval was 2.38 days (95%CrI 2.30-2.47) with about 51% (95%CrI 45-56%) of infections caused by symptomatic individuals being generated before symptom onset. These results indicate that the intrinsic generation time of the SARS-CoV-2 Omicron variant might not have shortened as compared to previous estimates on ancestral lineages, Alpha and Delta, in the same geographic setting. Like for previous lineages, pre-symptomatic transmission appears to play a key role for Omicron transmission. Estimates in this study may be useful to design quarantine, isolation and contact tracing protocols and to support surveillance (e.g., for the accurate computation of reproduction numbers). The study was partially funded by EU grant 874850 MOOD.
Sections du résumé
Background
UNASSIGNED
Starting from the final months of 2021, the SARS-CoV-2 Omicron variant expanded globally, swiftly replacing Delta, the variant that was dominant at the time. Many uncertainties remain about the epidemiology of Omicron; here, we aim to estimate its generation time.
Methods
UNASSIGNED
We used a Bayesian approach to analyze 23,122 SARS-CoV-2 infected individuals clustered in 8903 households as determined from contact tracing operations in Reggio Emilia, Italy, throughout January 2022. We estimated the distribution of the intrinsic generation time (the time between the infection dates of an infector and its secondary cases in a fully susceptible population), realized household generation time, realized serial interval (time between symptom onset of an infector and its secondary cases), and contribution of pre-symptomatic transmission.
Findings
UNASSIGNED
We estimated a mean intrinsic generation time of 6.84 days (95% credible intervals, CrI, 5.72-8.60), and a mean realized household generation time of 3.59 days (95%CrI: 3.55-3.60). The household serial interval was 2.38 days (95%CrI 2.30-2.47) with about 51% (95%CrI 45-56%) of infections caused by symptomatic individuals being generated before symptom onset.
Interpretation
UNASSIGNED
These results indicate that the intrinsic generation time of the SARS-CoV-2 Omicron variant might not have shortened as compared to previous estimates on ancestral lineages, Alpha and Delta, in the same geographic setting. Like for previous lineages, pre-symptomatic transmission appears to play a key role for Omicron transmission. Estimates in this study may be useful to design quarantine, isolation and contact tracing protocols and to support surveillance (e.g., for the accurate computation of reproduction numbers).
Funding
UNASSIGNED
The study was partially funded by EU grant 874850 MOOD.
Identifiants
pubmed: 35791373
doi: 10.1016/j.lanepe.2022.100446
pii: S2666-7762(22)00140-5
pmc: PMC9246701
doi:
Types de publication
Journal Article
Langues
eng
Pagination
100446Informations de copyright
© 2022 The Author(s).
Déclaration de conflit d'intérêts
MA has received research funding from Seqirus. The funding is not related to COVID-19. All other authors declare no conflicts of interest.
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