The variant is characterized by 18 amino acid mutations – including N501Y, L452R and H655Y. There is evidence that the variant can spread faster than other strains of SARS-CoV-2.
The researchers write:
It remains to be seen whether HMN.19B will be less susceptible to protection by natural, therapeutic, or vaccine-induced immune responses. Several of its tip substitutions (N501Y, L452R and H655Y) have been shown to require higher levels of neutralizing antibodies to be controlled, both in vitro and in vivo. ”
Given the limited data available on this new variant, the study authors highlight an increased need for genomic surveillance and monitoring.
Initial detection of the HMN.19B variant
Researchers were alerted to a new variant of SARS-CoV-2 of interest on January 21, 2021, from the PCR test of an immunocompromised hospital staff member who presented with headaches, fatigue and rhinitis. Her partner from the same household and two nurses in close contact also tested positive for the variant. All four patients presented mild symptoms and did not require hospitalization.
The hospital staff member and his partner had a history of COVID-19 infection, but both had tested negative for anti-SARS-CoV-2 protein N antibodies in January 2021. One of the nurses had received his first dose of Pfizer-BioNTech vaccine 11 days before the test. positive for the virus.
Genomic monitoring of the variant
Genomic sequencing showed four cluster members infected with a new variant linked to clade 19B.
The variant contains 25 nucleotide substitutions, including 2 deletions and 8 amino acid substitutions on the SARS-CoV-2 spike protein.
Distribution of the HMN.19B variant in Paris
Four weeks later, researchers identified the HMN.19B variant in the genomic sequencing of 12 people living in Paris who tested positive for COVID-19 infection. This included an employee of the prison staff working in north-east Paris, three from the hematology department of a hospital and eight unrelated cases from February 3 to 23 in different Paris hospitals.
Simultaneously, the National Reference Center for Respiratory Viral Infections in Lyon, France, detected an additional 17 people with viruses closely related to the HMN.19B variant. Related viruses contained more than seven similar spike protein mutations. Three people were from the greater Paris area, 10 from the south-east of France and 4 from the south-west of France.