Sequencing of seasonal influenza virus applied to Public Health

Identifier:  TFG:1621

Handle: https://hdl.handle.net/20.500.11797/TFG1621

Authors:  García Anaya, Aitor

Abstract:
The objective of this work is to evaluate the effectiveness of the annual flu vaccine. To this end, viruses have first been identified in nasopharyngeal samples from hospitalized patients and influenza samples have been characterized. Once the type and subtype of each sample was known, an RT-PCR was performed to obtain complementary DNA (cDNA) of the glycoprotein hemagglutinin (HA), target of the antibodies generated in the vaccination, which was subsequently sequenced. The sequences of the samples were compared with the sequences of the strains included in the annual vaccine. The study of mutations has allowed to differentiate the samples in groups or clades that share mutations. The ability of the virus to evade the antibodies produced after exposure to the vaccine has been evaluated from mutations in residues located in epitopes of HA and variations in glycosylation potential. The differentiation of 2 main clades of the A / H3N2 virus with multiple mutations in epitopes of the HA and the appearance of a new clade of B / Victoria characterized by having a deletion of two amino acids, suggested that the vaccine of the 2018-2019 season should be updated. On the other hand, the A / H1N1pdm09 and B / Yamagata viruses showed low variation, so it did not seem necessary to update the strains included in the vaccine.