Molecular findings from influenza A(H1N1)pdm09 detected in patients from a Brazilian equatorial region during the pandemic period

Abstract

After the World Health Organization officially declared the end of the first pandemic of the XXI century in August 2010, the influenza A(H1N1)pdm09 virus has been disseminated in the human population. In spite of its sustained circulation, very little on phylogenetic data or oseltamivir (OST) resistance is available for the virus in equatorial regions of South America. In order to shed more light on this topic, we analysed the haemagglutinin (HA) and neuraminidase (NA) genes of influenza A(H1N1)pdm09 positive samples collected during the pandemic period in the Pernambuco (PE), a northeastern Brazilian state. Complete HA sequences were compared and amino acid changes were related to clinical outcome. In addition, the H275Y substitution in NA, associated with OST resistance, was investigated by pyrosequencing. Samples from PE were grouped in phylogenetic clades 6 and 7, being clustered together with sequences from South and Southeast Brazil. The D222N/G HA gene mutation, associated with severity, was found in one deceased patient that was pregnant. Additionally, the HA mutation K308E, which appeared in Brazil in 2010 and was only detected worldwide the following year, was identified in samples from hospitalised cases. The resistance marker H275Y was not identified in samples tested. However, broader studies are needed to establish the real frequency of resistance in this Brazilian region.

The high frequency of non-aspartic acid residues at HA222 in influenza A(H1N1) 2009 pandemic viruses is associated with mortality during the upsurge of 2015: a molecular and epidemiological study from central India

“…Studies determining whether this drift has resulted in a re-infection with A(H1N1)pdm09 or infection despite prior vaccination will be interesting. The detection of two peaks at nucleotides 715 and/ or 716 (amino acid D222) indicate an infection by a quasi-species, which has also been reported in previous studies [37] using pyrosequencing [38] and nextgeneration sequencing results [14,39] to confirm the findings from Sanger sequencing results. Sanger sequencing is a good indicator of mixed infections, if the site-specific mutations are known.…”

Impact of Pregnancy on Intra-Host Genetic Diversity of Influenza A Viruses in Hospitalised Women: A Retrospective Cohort Study

“…Seven non-synonymous ihSNV on PA (E493A), NP (T130K) and HA (P182Q, T342A, E356K) of H1N1, and on PB1 (K279Q, Q460K) of both H3N2 and H1N1 viruses were shared by several samples. None has been reported elsewhere except for HA P182Q, detected in out- and hospitalised patients in Brazil during the 2009 pandemic [15]. None of these shared ihSNV were significantly associated with pregnancy but there was a trend towards higher occurrence of PB1 K279Q and Q460K in pregnant women.…”

Immunogenicity and sustainability of the immune response in Brazilian HIV‐1‐infected individuals vaccinated with inactivated triple influenza vaccine

“…Thus, besides the regular updates in the influenza vaccine composition, which requires annual vaccination, the lack of seroprotection in around 40% of our cohort 12 months after vaccination highlights the need for regular vaccination of HIV‐infected individuals against influenza. Since Brazil encompasses distinct temperate and tropical climatic zones, the influenza season may vary from region to region [Ministério da Saúde, ; Moura et al, ; Oliveira et al, ; Silva et al, ]. Whether there would be value in giving influenza vaccine in different schedules, depending on the geographical region, merits further study.…”