The 19B / 501Y Henri Mondor variant (lineage A.27) has been detected in France since January 2021 infrequently but overall stable, with fluctuations from one week to the next: it represented 1% of sequences interpretable in the Flash # 6 survey (03/30/2021) versus 0.2% in the Flash # 5 survey (03/16/2021). In week 13, 18 detections of this variant were reported by the EMERGEN consortium. The clusters of large size that have been detected in connection with this variant have been closed to date, although strings of intrafamily transmission continue to be detected, particularly in the PACA region.
However, several points of attention should be noted and justify continuing the reinforced surveillance of this variant. First of all, it was detected in several large clusters, affecting school establishments, care (including hospitals, SSR and nursing homes) or military, especially in Ile-de-France (hospital and intra-family clusters), Pays de la Loire (3 clusters mainly affecting school establishments and military), Brittany (1 cluster in nursing homes in Morbihan) and Nouvelle-Aquitaine (6 clusters affecting healthcare establishments in Dordogne).
Maintaining sporadic detection of this variant on the national territory indicates a community transmission with low noise. At this point it seems less competitive than VOC 20I / 501Y.V1, since its prevalence remains much lower than the latter, including in geographic areas where it appears to have disseminated more extensively than nationally during of the 1st quarter of 2021 (Dordogne and Ile-de-France in particular).
In addition, three cases considered to be probable reinfections were identified 9 with confirmation of infection with this variant during the second episode, without it being possible to date to estimate the frequency of re-infections with this variant, nor to compare it with that of other viral strains circulating in France.
Data is still lacking at this stage on the clinical features of infection with this variant, but we did not detect a signal in favor of a significant impact on its transmissibility or an increased severity of the infection caused by this variant compared to the reference viral strains or variants of concern.
The VOI 19B / 501Y (lineage A.27) has been detected infrequently but regularly in France since January 2021. It represented 1.8% of the interpretable sequences during the Flash # 4 survey versus 0% during the Flash Inquiry # 3. In weeks 10 and 11, respectively 48 and 47 detections of this variant were reported by the 4 national sequencing platforms.
However, several points of attention should be note and justify continuing the reinforced surveillance of this variant. First, it was detected during several clusters, a priori all closed, affecting schools, healthcare (including centers hospitals, SSR and Ehpad) or military, with for some a high number of COVID-19 cases (more around sixty), particularly in Ile-de-France (2 hospital clusters and 8 intra-family clusters), Pays de la Loire (3 clusters), Brittany (1 cluster in Morbihan) and Nouvelle-Aquitaine (6 clusters in Dordogne).
Community transmission of this variant is suspected in at least two departments (Seine-et-Marne et Dordogne), and additional investigations are currently being carried out by the ARS concerned, in conjunction with SpF and CNR, to characterize this signal. In addition, three cases considered as probable re-infections were identified with confirmation of infection with this variant during the second episode, without it being possible to date to estimate the frequency of re-infections with this variant, nor to compare it with that of other viral strains circulating in France.
Data is still lacking at this stage on the clinical features of infection with this variant, but we did not detect a signal in favor of significant impact on its transmissibility or increased severity of infection caused by this variant. The strengthening of the surveillance of this variant should be able to more precisely document its characteristics, which will be noted to you when additional data becomes available.
French Health Department – Risk analysis related to emerging variants of SARS-COV-2 (PDF)
We report a novel severe acute respiratory syndrome coronavirus 2 variant derived from clade 19B (HMN.19B variant or Henri Mondor variant). This variant is characterized by the presence of 18 amino acid substitutions, including 7–8 substitutions in the spike protein and 2 deletions. These variants actively circulate in different regions of France.
We identified a new, previously undescribed variant of SARS-CoV-2 (HMN.19B or Henri Mondor variant) within a cluster of hospital staff in Paris. This variant stems from an older SARS CoV-2 clade, 19B, which emerged in late 2019 but have been rarely detected since early 2020, overtaken by clades 20A, 20B, and 20C, which harbor the D614G substitution believed to improve viral transmission (1). The HMN.19B variant is characterized by the presence of 2 deletions and 18 amino acid substitutions over the entire sequence, including 8 substitutions within the spike protein, some of which are common with other recently described variants, a finding in keeping with the ongoing evolutionary convergence of SARS-CoV-2 variants. The acquisition of spike substitutions, including N501Y and L452R, has been suggested to enhance the interaction of spike with the angiotensin-converting enzyme 2 viral receptor. The resulting substantial fitness acquisition could explain the reappearance of clade 19B
In the 4 weeks after its first detection, our laboratory, which maintains 1 of the 4 national SARS CoV-2 sequencing surveillance platforms in France, found the HMN.19B variant in 12 patients from the greater Paris area