An observational study of breakthrough SARS-CoV-2 Delta variant infections among vaccinated healthcare workers in Vietnam.

BACKGROUND: Data on breakthrough SARS-CoV-2 Delta variant infections in vaccinated individuals are limited. METHODS: We studied breakthrough infections among Oxford-AstraZeneca vaccinated healthcare workers in an infectious diseases hospital in Vietnam. We collected demographic and clinical data alongside serial PCR testing, measurement of SARS-CoV-2 antibodies, and viral whole-genome sequencing. FINDINGS: Between 11th-25th June 2021 (7-8 weeks after the second dose), 69 staff tested positive for SARS-CoV-2. 62 participated in the study. Most were asymptomatic or mildly symptomatic and all recovered. Twenty-two complete-genome sequences were obtained; all were Delta variant and were phylogenetically distinct from contemporary viruses obtained from the community or from hospital patients admitted prior to the outbreak. Viral loads inferred from Ct values were 251 times higher than in cases infected with the original strain in March/April 2020. Median time from diagnosis to negative PCR was 21 days (range 8-33). Neutralizing antibodies (expressed as percentage of inhibition) measured after the second vaccine dose, or at diagnosis, were lower in cases than in uninfected, fully vaccinated controls (median (IQR): 69.4 (50.7-89.1) vs. 91.3 (79.6-94.9), p=0.005 and 59.4 (32.5-73.1) vs. 91.1 (77.3-94.2), p=0.002). There was no correlation between vaccine-induced neutralizing antibody levels and peak viral loads or the development of symptoms. INTERPRETATION: Breakthrough Delta variant infections following Oxford-AstraZeneca vaccination may cause asymptomatic or mild disease, but are associated with high viral loads, prolonged PCR positivity and low levels of vaccine-induced neutralizing antibodies. Epidemiological and sequence data suggested ongoing transmission had occurred between fully vaccinated individuals. FUNDING: Wellcome and NIH/NIAID.

Duration of viral detection in throat and rectum of a patient with COVID-19

The rapid spread of coronavirus disease 2019 (COVID-19) raises concern about a global pandemic. Knowledge about the duration of viral shedding remains important for patient management and infection control. We report the duration of viral detection in throat and rectum of a COVID-19 patient treated at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam. Despite clinical recovery, SARS-CoV-2 RNA remained detectable by real time RT-PCR in throat and rectal swabs until day 11 and 18 of hospitalization, respectively. Because live SARS-CoV-2 has been successfully isolated from a stool sample from a COVID-19 patient in China, the results demonstrate that COVID-19 patients may remain infectious for long periods, and fecal-oral transmission may be possible. Therefore, our finding has important implications for infection control.

Anti-Inflammatory and Anti-Oxidative Activities of Phenolic Compounds from Alnus sibirica Stems Fermented by Lactobacillus plantarum subsp. argentoratensis.

Fermentation of Alnus sibirica (AS) stems using Lactobacillus plantarum subsp. argentoratensis was conducted and three compounds isolated from the Alnus species were identified for the first time, 7-(3,4-dihydroxyphenyl)-1-(4-hydroxyphenyl)-heptan-3-one, 1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptan-3-one and 4-(3,4-dihydroxyphenyl)-butan-2-one, along with 14 known compounds. The anti-oxidative and anti-inflammatory abilities of AS and fermented AS (FAS) as well as the isolated phenolic compounds from FAS were investigated. FAS showed stronger anti-oxidative and anti-inflammatory activities than non-fermented AS.

Antioxidative and Anti-Inflammatory Activities of Galloyl Derivatives and Antidiabetic Activities of Acer ginnala.

Chromatographic isolation of the 80% MeOH extract of Acer ginnala (AG) yielded seven galloyl derivatives: gallic acid (1), ginnalin B (2), acertannin (3), maplexin D (4), maplexin E (5), quercetin-3-O-(2''-galloyl)-α-L-rhamnopyranoside (6), and kaempferol-3-O-(2''-galloyl)-α-L-rhamnopyranoside (7). This is the first study to report the isolation of compounds 4 and 5 from AG. Galloyl derivatives 3-7 exhibited potent radical scavenging activities, with 5 and 7 showing particularly strong inhibitory activities against nitric oxide production in lipopolysaccharides- (LPS-) stimulated RAW264.7 cells. In addition, oral administration of AG extract (500 mg/kg b.w.) improved symptoms of hyperglycemia and blunted the increases in serum GOT/GPT levels in a rat model of streptozotocin-induced diabetes. These results suggest that galloyl derivatives (1-7) are antioxidant and anti-inflammatory agents and that AG extract has potential as a functional material or novel herbal medicine for treating diabetes mellitus.

Inhibitory Activities of Phenolic Compounds Isolated from Adina rubella Leaves Against 5α-Reductase Associated with Benign Prostatic Hypertrophy.

Adina rubella Hance (AR), a plant native to Korea, has been used as traditional medicine for dysentery, eczema, intoxication, and external hemorrhages. Previous phytochemical studies of AR have reported several components, including terpenoids, phenolics, and alkaloids. The current study evaluated the anti-oxidative and anti-inflammatory activities and 5α-reductase inhibition of isolated compounds of AR leaves to find a potential therapeutic agent for benign prostatic hypertrophy (BPH). Repeated chromatographic isolation of an 80% acetone extract of AR leaves yielded seven phenolic compounds: caffeic acid (1), chlorogenic acid (2), methyl chlorogenate (3), quercetin-3-rutinoside (4), kaempferol-3-O-α-l-rhamnopyranosyl-(1→6)-ß-d-glucopyranoside (5), hyperoside (6), and grandifloroside (7). Compound 7 is a novel compound in AR. Caffeoyl derivatives 1-3 and 7 showed good anti-oxidative activities. In particular, caffeic acid (1) and grandifloroside (7) showed potent anti-inflammatory activities, and 7 also exhibited potent inhibitory activity against TNF-α and 5α-reductase. Our results show that the extract and grandifloroside (7) from leaves of AR might be developed as a source of potent anti-oxidative and anti-inflammatory agents and therapeutic agent for BPH.

Phylodynamics of Enterovirus A71-Associated Hand, Foot, and Mouth Disease in Viet Nam.

UNLABELLED: Enterovirus A71 (EV-A71) is a major cause of hand, foot, and mouth disease (HFMD) and is particularly prevalent in parts of Southeast Asia, affecting thousands of children and infants each year. Revealing the evolutionary and epidemiological dynamics of EV-A71 through time and space is central to understanding its outbreak potential. We generated the full genome sequences of 200 EV-A71 strains sampled from various locations in Viet Nam between 2011 and 2013 and used these sequence data to determine the evolutionary history and phylodynamics of EV-A71 in Viet Nam, providing estimates of the effective reproduction number (Re) of the infection through time. In addition, we described the phylogeography of EV-A71 throughout Southeast Asia, documenting patterns of viral gene flow. Accordingly, our analysis reveals that a rapid genogroup switch from C4 to B5 likely took place during 2012 in Viet Nam. We show that the Re of subgenogroup C4 decreased during the time frame of sampling, whereas that of B5 increased and remained >1 at the end of 2013, corresponding to a rise in B5 prevalence. Our study reveals that the subgenogroup B5 virus that emerged into Viet Nam is closely related to variants that were responsible for large epidemics in Malaysia and Taiwan and therefore extends our knowledge regarding its associated area of endemicity. Subgenogroup B5 evidently has the potential to cause more widespread outbreaks across Southeast Asia. IMPORTANCE: EV-A71 is one of many viruses that cause HFMD, a common syndrome that largely affects infants and children. HFMD usually causes only mild illness with no long-term consequences. Occasionally, however, severe infection may arise, especially in very young children, causing neurological complications and even death. EV-A71 is highly contagious and is associated with the most severe HFMD cases, with large and frequent epidemics of the virus recorded worldwide. Although major advances have been made in the development of a potential EV-A71 vaccine, there is no current prevention and little is known about the patterns and dynamics of EV-A71 spread. In this study, we utilize full-length genome sequence data obtained from HFMD patients in Viet Nam, a geographical region where the disease has been endemic since 2003, to characterize the phylodynamics of this important emerging virus.

Early pandemic influenza (2009 H1N1) in Ho Chi Minh City, Vietnam: a clinical virological and epidemiological analysis.

BACKGROUND: To date, little is known about the initial spread and response to the 2009 pandemic of novel influenza A ("2009 H1N1") in tropical countries. Here, we analyse the early progression of the epidemic from 26 May 2009 until the establishment of community transmission in the second half of July 2009 in Ho Chi Minh City (HCMC), Vietnam. In addition, we present detailed systematic viral clearance data on 292 isolated and treated patients and the first three cases of selection of resistant virus during treatment in Vietnam. METHODS AND FINDINGS: Data sources included all available health reports from the Ministry of Health and relevant health authorities as well as clinical and laboratory data from the first confirmed cases isolated at the Hospital for Tropical Diseases in HCMC. Extensive reverse transcription (RT)-PCR diagnostics on serial samples, viral culture, neuraminidase-inhibition testing, and sequencing were performed on a subset of 2009 H1N1 confirmed cases. Virological (PCR status, shedding) and epidemiological (incidence, isolation, discharge) data were combined to reconstruct the initial outbreak and the establishment of community transmission. From 27 April to 24 July 2009, approximately 760,000 passengers who entered HCMC on international flights were screened at the airport by a body temperature scan and symptom questionnaire. Approximately 0.15% of incoming passengers were intercepted, 200 of whom tested positive for 2009 H1N1 by RT-PCR. An additional 121 out of 169 nontravelers tested positive after self-reporting or contact tracing. These 321 patients spent 79% of their PCR-positive days in isolation; 60% of PCR-positive days were spent treated and in isolation. Influenza-like illness was noted in 61% of patients and no patients experienced pneumonia or severe outcomes. Viral clearance times were similar among patient groups with differing time intervals from illness onset to treatment, with estimated median clearance times between 2.6 and 2.8 d post-treatment for illness-to-treatment intervals of 1-4 d, and 2.0 d (95% confidence interval 1.5-2.5) when treatment was started on the first day of illness. CONCLUSIONS: The patients described here represent a cross-section of infected individuals that were identified by temperature screening and symptom questionnaires at the airport, as well as mildly symptomatic to moderately ill patients who self-reported to hospitals. Data are observational and, although they are suggestive, it is not possible to be certain whether the containment efforts delayed community transmission in Vietnam. Viral clearance data assessed by RT-PCR showed a rapid therapeutic response to oseltamivir.