Mary Wilson
Well-known member
09/Jan/2025
https://doi.org/10.2807/1560-7917.ES.2025.30.1.2400293
Adriana Traore¹ , Kelly Charniga² , Sophie Grellet3,* , Garance Terpant3,* , Héléna Da Cruz3,* , Anais Lamy3,* , Nathalie Thomas3,*, Gwladys Gbaguidi3,* , Alizé Mercier3,* , Julie Prudhomme3,* , Benoit Visseaux⁴ , Vincent Vieillefond⁵ , Stéphanie Haim-Boukobza⁶, Jean-Marc Giannoli⁷ , RELAB Study Group⁸ , Laboratory group⁹ , Javier Castro-Alvarez¹ , Alain-Claude Kouamen¹ , Marie-Anne Rameix-Welti10,11 , Samar Beirrera-Ibraim10 , Gregory Destras12 , Laurence Josset12 , Simon Cauchemez² , Bruno Lina12 , Bruno Coignard¹ , Justine Schaeffer¹ , Vincent Enouf10 , Antonin Bal12
Background: Early detection and characterisation of
SARS-CoV-2 variants have been and continue to be
essential for assessing their public health impact.
In August 2023, Santé publique France implemented
enhanced surveillance for BA.2.86 and sub-lineage
JN.1 because of their genetic divergence from other
variants and increased prevalence.
Aim: To detail how combining epidemiological and
laboratory data sources, targeted investigations and
modelling ena-bled comprehensive characterisation
of sub-lineage JN.1.
Methods: Data were collected from epidemiologi-
cal investigations using a standardised questionnaire
and from routine and novel (RELAB network) surveil-
lance systems. JN.1 cases were compared with cases
infected with previously circulating variants, such as
EG.5, BA.4/BA.5 and other BA.2.86 sub-lineages. The
growth rate and doubling time of JN.1 were estimated.
Results: JN.1 was first detected in September 2023 in
the Île-de-France region, France, and spread widely
across the country. By late November, doubling time
was estimated to be 8.6 to 26.4 days depending on
the region. For all data sources, cases infected by JN.1
showed similar demographics, rates of hospitalisa-
tion and RT-PCR cycle threshold values compared with
those infected by previous variants. JN.1 cases also
had older median age (54 years; 40–71 vs 47 years;
30–59), more frequent reports of feverish feeling
and less frequent cough or nausea compared with
BA.4/BA.5 cases. JN.1 cases had significantly higher
frequency of anosmia compared with other BA.2.86
cases.
Conclusion: Combining different data sources
played a key role in detecting emerging variant JN.1,
for which no evidence of increased public health
impact was found despite its genetic divergence.
https://www.eurosurveillance.org/do...?expires=1736483898&id=id&accname=guest&check sum=EA044CCE21075B2733C6135F2CB0D1DB
https://doi.org/10.2807/1560-7917.ES.2025.30.1.2400293
Adriana Traore¹ , Kelly Charniga² , Sophie Grellet3,* , Garance Terpant3,* , Héléna Da Cruz3,* , Anais Lamy3,* , Nathalie Thomas3,*, Gwladys Gbaguidi3,* , Alizé Mercier3,* , Julie Prudhomme3,* , Benoit Visseaux⁴ , Vincent Vieillefond⁵ , Stéphanie Haim-Boukobza⁶, Jean-Marc Giannoli⁷ , RELAB Study Group⁸ , Laboratory group⁹ , Javier Castro-Alvarez¹ , Alain-Claude Kouamen¹ , Marie-Anne Rameix-Welti10,11 , Samar Beirrera-Ibraim10 , Gregory Destras12 , Laurence Josset12 , Simon Cauchemez² , Bruno Lina12 , Bruno Coignard¹ , Justine Schaeffer¹ , Vincent Enouf10 , Antonin Bal12
Background: Early detection and characterisation of
SARS-CoV-2 variants have been and continue to be
essential for assessing their public health impact.
In August 2023, Santé publique France implemented
enhanced surveillance for BA.2.86 and sub-lineage
JN.1 because of their genetic divergence from other
variants and increased prevalence.
Aim: To detail how combining epidemiological and
laboratory data sources, targeted investigations and
modelling ena-bled comprehensive characterisation
of sub-lineage JN.1.
Methods: Data were collected from epidemiologi-
cal investigations using a standardised questionnaire
and from routine and novel (RELAB network) surveil-
lance systems. JN.1 cases were compared with cases
infected with previously circulating variants, such as
EG.5, BA.4/BA.5 and other BA.2.86 sub-lineages. The
growth rate and doubling time of JN.1 were estimated.
Results: JN.1 was first detected in September 2023 in
the Île-de-France region, France, and spread widely
across the country. By late November, doubling time
was estimated to be 8.6 to 26.4 days depending on
the region. For all data sources, cases infected by JN.1
showed similar demographics, rates of hospitalisa-
tion and RT-PCR cycle threshold values compared with
those infected by previous variants. JN.1 cases also
had older median age (54 years; 40–71 vs 47 years;
30–59), more frequent reports of feverish feeling
and less frequent cough or nausea compared with
BA.4/BA.5 cases. JN.1 cases had significantly higher
frequency of anosmia compared with other BA.2.86
cases.
Conclusion: Combining different data sources
played a key role in detecting emerging variant JN.1,
for which no evidence of increased public health
impact was found despite its genetic divergence.
https://www.eurosurveillance.org/do...?expires=1736483898&id=id&accname=guest&check sum=EA044CCE21075B2733C6135F2CB0D1DB
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