New COVID Variant JN.1 Eludes Recent Vaccine Booster Efforts
The most recent series of Covid-19 vaccines provided no additional defense against the JN.1 variant, which remains in circulation.
JN.1, from the lineage of Omicron, is an off-spin of BA.2.86.The variant, first detected in Luxembourg in August, was classified as a variant of interest (VOI) by the World Health Organization (WHO) due to its rapid spread.
JN.1 Variant's L455S Mutation May Enhance Immune Evasion Against XBB 1.5 Boosters
The additional mutation L455S in the spike protein of JN.1 is believed to have provided the variant with immune-evasion properties. The study, appearing on a preprint site and not peer-reviewed yet, examined the efficacy of XBB 1.5 boosters on the JN.1 variant among 76 people. The findings showed that the vaccine provided better coverage overall, but the globally dominant JN.1 managed to evade them ().‘The revised XBB.1.5 booster notably enhanced titers against recent variants, excluding JN.1. #COVID #JN #boosters ’
"Remarkably, while many individual mutations that emerged between 2020 and 2022 exhibit escape from sera following primary vaccination, few escape boosted sera," said Alejandro B. Balazs, from Ragon Institute of Massachusetts General Hospital, in the paper.
Importantly, the team also found that newly emerging Covid variants have "more efficient ways of entering cells", besides the common entry point - ACE2.
"In addition to escape from vaccine sera, we found that mutations also contribute significantly to the ability of pseudovirus to infect cells, suggesting that variant selection is optimizing both antibody escape and viral entry. We found that spikes from variants post BA.1 produced pseudoviruses that were up to 30-fold better at transducing target cells than wild-type, suggesting that WT SARS-CoV-2 spike was not optimally configured for ACE2-dependent viral entry," the team said.
Although seasonal boosters improve immunity against new strains, the immune escape potential of the "variants demonstrate the need for novel approaches to adequately control SARS-CoV-2 transmission", the team said.
Reference:
- Ongoing evolution of SARS-CoV-2 drives escape from mRNA vaccine-induced humoral immunity - (https:www.ncbi.nlm.nih.gov/pmc/articles/PMC10942518/)
Source: IANS