1.Oseltamivir resistance among influenza viruses: surveillance in northern Viet Nam, 2009–2012
Hoang Vu Mai-Phuong ; Nguyen Co Thach ; Nguyen Le Khanh Hang ; Nguyen Thi Kim Phuong ; Le Quynh Mai
Western Pacific Surveillance and Response 2013;4(2):26-33
Introduction: Antiviral resistance has been reported in seasonal influenza A viruses and avian influenza A(H5N1) viruses in Viet Nam, raising concerns about the efficacy of treatment.
Methods: We analysed specimens from two sources during the period 2009–2012: influenza-positive samples from influenza-like illness patients at sentinel clinics in northern Viet Nam and isolates from patients with confirmed A(H5N1) infections. Pyrosequencing was used to detect mutations: H275Y [for A(H1N1) and A(H5N1)], E119V [for A(H3N2)] and I117V [for A(H5N1)]. A neuraminidase inhibition assay was used to determine the Inhibitory Concentration 50 (IC50) values for all influenza A and B isolates.
Results: There were 341 influenza A positive samples identified; influenza A(H1N1)pdm09 was identified most frequently (n = 215). In 2009, oseltamivir resistance was observed in 100% (19 of 19) of seasonal A(H1N1) isolates and 1.4% (3/215) of A(H1N1)pdm09 isolates. This H275Y mutation was not found in influenza subtypes A(H5N1) or A(H3N2) isolates.
Discussion: In Viet Nam, seasonal and A(H5N1) influenza vaccines are not currently available; thus, effective treatment is required. The presence of oseltamivir-resistant viruses is therefore a concern. Active surveillance for oseltamivir resistance among influenza viruses circulating in Viet Nam should be continued.
2.Circulation of influenza B lineages in northern Viet Nam, 2007–2014
Thi Thanh Le ; Thu Hang Pham ; Thi Hien Pham ; Le Khanh Hang Nguyen ; Co Thach Nguyen ; Vu Mai Phuong Hoang ; Thu Huong Tran ; Vu Son Nguyen ; Huong Giang Ngo ; Quynh Mai Le
Western Pacific Surveillance and Response 2015;6(4):17-23
3.Occurrence of the Omicron variant of SARS-CoV-2 in northern Viet Nam in early 2022
Trang thi Hong Ung ; Phuong Vu Mai Hoang ; Son Vu Nguyen ; Hang Le Khanh Nguyen ; Phuong thi Kim Nguyen ; Dan Tan Phan ; Thanh Thi Le ; Anh Phuong Nguyen ; Thach Co Nguyen ; Futoshi Hasebe ; Mai thi Quynh Le
Western Pacific Surveillance and Response 2022;13(3):29-33
The Omicron variant caused a surge of infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Viet Nam in early 2022, signalling community transmission. We report on active whole-genome sequencing surveillance of positive SARS-CoV-2 samples collected at that time in northern Viet Nam from international arrivals and community clusters. We used an amplicon protocol developed with 14 polymerase chain reaction products and the Illumina iSeq 100 platform. Overall, 213 nasopharyngeal or throat swabs were analysed, of which 172 samples were identified with the Omicron variant. Of these, 80 samples were collected from community cases in February 2022, among which 59 samples were sublineage BA.2 and one sample was the recombinant XE variant. Our results indicated that Omicron had replaced Delta as the dominant variant in a very short period of time and that continuously conducting active whole-genome sequencing surveillance is necessary in monitoring the evolution and genomic diversity of SARS-CoV-2 in Viet Nam.