Circulation of human respiratory syncytial virus and new ON1 genotype in northern Viet Nam, 2017-2020.

Objective: Human respiratory syncytial virus (RSV) is a primary cause of paediatric severe acute respiratory infection (SARI) worldwide, especially in developing countries. We investigated the genetic characteristics of RSV in northern Viet Nam to determine the prevalence and distribution of subtypes as well as the diversity and transmission patterns of genotypes. Methods: In two facilities, from January 2017 to December 2020, 1563 clinical specimens were collected from paediatric patients hospitalized with SARI and tested for RSV. Selected positive samples underwent sequencing analysis targeting the second hypervariable region of the G gene using next-generation sequencing. Results: The RSV positivity rate was 28.02% (438/1563 samples), and prevalence was highest in children aged < 1 year (43.84%; 192/438). Subtype RSV-A accounted for 53.42% (234/438) of cases, RSV-B for 45.89% (201/438), and there was coinfection in 0.68% (3/438). Both subtypes cocirculated and peaked during August-September in each year of the study. Phylogenetic analysis showed that RSV-A samples belonged to the ON1 genotype, which has three subgenotypes: ON1.1, ON1.2 and ON1.3. However, we did not find the 72-nucleotide duplication in the second hypervariable region of the G gene, a characteristic of genotype ON1, in any RSV-A samples. RSV-B samples belonged to genotype BA9. Discussion: Our results provide additional molecular characterization of RSV infections in Viet Nam. Specially, our study is the first to report the absence of the 72-nucleotide duplication in the G gene of RSV-A genotype ON1 in Viet Nam, which may help in understanding the genetic evolution of RSV and be useful for vaccine development in the future.

Investigation of SARS-CoV-2 presence on environmental surfaces and waste in healthcare and non-healthcare facilities.

Objective: The objective of the paper is to investigate the presence of SARS-CoV-2 on inanimate surfaces in four healthcare facilities treating patients with COVID-19 and four quarantine regiments of provincial military commands. Methods: From August to October 2020, a total of 468 one-off environmental samples consisting of inanimate surfaces, garbage, and wastewater were collected. The real-time RT-PCR assay targeting E and RdRp genes to detect SARS-CoV-2 and checklist and questionnaire of disinfection practices were employed. If detected by RT-PCR, then positive samples are subjected to cell culture to determine viability. Results: The test results showed all samples (100%) to be negative with SARS-CoV-2 resulting in unperformed virus culture. As for recent disinfection practices, chlorine-based products dissolved at a concentration of 0.1% (1000 ppm) in the general context or 0.5% (5000 ppm) for blood and body fluid spills are routinely applied twice a day and at the discharge of patients or quarantined people. Conclusions: The finding may illustrate the importance of disinfection practices in removing pathogens or significantly reducing SARS-CoV-2 contamination on environmental surfaces and waste.

Novel Mutation of SARS-CoV-2, Vietnam, July 2020.

A cluster of severe acute respiratory syndrome coronavirus 2 infections in Danang, Vietnam, began July 25, 2020, and resulted in 551 confirmed cases and 35 deaths as of February 2021. We analyzed 26 sequences from this cluster and identified a novel shared mutation in nonstructural protein 9, suggesting a single introduction into Vietnam.