As authorities braced for the arrival of the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), infrastructure investments and government directives prompted action in central Viet Nam to establish capacity for genomic surveillance sequencing. From 17 November 2021 to 7 January 2022, the Pasteur Institute in Nha Trang sequenced 162 specimens from 98 150 confirmed SARS-CoV-2 cases in the region collected from 8 November to 31 December 2021. Of these, all 127 domestic cases were identified as the B.1.617.2 (Delta) variant, whereas 92% (32/35) of imported cases were identified as the B.1.1.529 (Omicron) variant, all among international flight passengers. Patients were successfully isolated, enabling health-care workers to prepare for additional cases. Most (78%) of the 32 Omicron cases were fully vaccinated, suggesting continued importance of public health and social measures to control the spread of new variants.
Molecular genetic studies of 221 strains of enteroviruses isolated from patients with HFMD and neuroinfections from different provinces of Vietnam in 2018-2021 were carried out. 20 types of enteroviruses have been identified: CVA2, CVA4, CVA5, CVA6, CVA8, CVA10, CVA16, EV-A71, CVA9, CVB1, CVB2, CVB4, ECHO4, ECHO6, ECHO9, ECHO11, ECHO16, ECHO29, ECHO25, ECHO30. Genetic heterogeneity of Vietnamese enterovirus strains has been established.
Objective: Measles, rubella, mumps, and varicella are currently endemic in Vietnam, but population immunity to the four diseases among the general population has not been well investigated. This study measured specific immunoglobulin (Ig)G in 362 randomly selected adults between 20 and 70 years old, using residual serum samples to evaluate age-specific immunity to the four diseases in Khanh Hoa province.Results: Age-specific anti-measles IgG prevalence was lowest, at 89.3% (95% confidence interval 71.8–97.7%) at 20–24 years old, below the herd immunity threshold of 95% to prevent epidemics. About 71.4–90.3% of women of child-bearing age (20–49 years old) were seropositive for rubella, indicating that a certain proportion of babies are at risk of congenital rubella syndrome. A large proportion of young adults (20–29 years) are susceptible to mumps and varicella, with population immunity of 71.4–78.1% to mumps and 48.8–53.6% to varicella. Population-based seroprevalence surveys of both children and adults are needed to evaluate population immunity and improve current immunization programs by expanding the target ages for immunization and introducing new vaccines.
Objective: To determine whether environmental surface contamination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred at a provincial hospital in Viet Nam that admitted patients with novel coronavirus disease 2019 (COVID-19) and at the regional reference laboratory responsible for confirmatory testing for SARS-CoV-2 in 2020. Methods: Environmental samples were collected from patient and staff areas at the hospital and various operational and staff areas at the laboratory. Specimens from frequently touched surfaces in all rooms were collected using a moistened swab rubbed over a 25 cm2 area for each surface. The swabs were immediately transported to the laboratory for testing by real-time reverse transcription polymerase chain reaction (RT-PCR). Throat specimens were collected from staff at both locations and were also tested for SARS-CoV-2 using real-time RT-PCR. Results: During the sampling period, the laboratory tested 6607 respiratory specimens for SARS-CoV-2 from patients within the region, and the hospital admitted 9 COVID-19 cases. Regular cleaning was conducted at both sites in accordance with infection prevention and control (IPC) practices. All 750 environmental samples (300 laboratory and 450 hospital) and 30 staff specimens were negative for SARS-CoV-2. Discussion: IPC measures at the facilities may have contributed to the negative results from the environmental samples. Other possible explanations include sampling late in a patient’s hospital stay when virus load was lower, having insufficient contact time with a surface or using insufficiently moist collection swabs. Further environmental sampling studies of SARS-CoV-2 should consider including testing for the environmental presence of viruses within laboratory settings, targeting the collection of samples to early in the course of a patient’s illness and including sampling of confirmed positive control surfaces, while maintaining appropriate biosafety measures.
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