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A 15-year study of #neuraminidase #mutations and the increasing of S247N mutation in #Spain

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By G.M.

Highlights

• In a landscape of a very narrow arsenal of influenza antivirals, resistance mutations are a significant threat.

• Resistance mutations were present in 0.5-5% in A and B influenza viruses during the last 15 years.

• However, S247N resistance mutation in the NA gene sharply increased during 2023-2024 season.

• While this mutation does not confer strong resistance by itself, their fixation could increase the risk of resistance in the future if other resistance mutations appears or get fixed together with it.


Abstract

The therapeutic arsenal against influenza is extremely limited and resistance often arises due to the emergence of mutations, especially in the neuraminidase (NA) gene. This study aimed to evaluate the evolution of NA mutations over 15 years in Spain. To do so, we used the GISAID database from which we downloaded a total of 11,125 influenza A(H1N1)pdm09, A(H3N2), B/Victoria and B/Yamagata NA virus sequences, and analyzed the resistance mutations using FluSurver software. Our results showed that the occurrence of NA resistance mutations remained constant in the four viruses during the 15 seasons evaluated, being around 0.5-5%. Most of the resistance was found in the A(H1N1)pdm09 subtype (around 70%), especially from the 2023-2024 season onwards, when a significant increase in the occurrence of S247N mutation was observed. The occurrence of this type of mutation before 2022 was rare, but in the 2023-2024 season a total of 44 influenza viruses harboring S247N mutations were detected, while in the other years, only two cases were observed. Some studies have described a significant increase in this mutation over the past two seasons and although it appears to confer only slightly reduced inhibition to oseltamivir, its increase is noteworthy and should be a reason for increased their vigilance.

Source: Virus Research, https://www.sciencedirect.com/science/article/pii/S0168170225000760?via%3Dihub

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