Age-dependent impairment in antibody responses elicited by a homologous CoronaVac booster dose

The emergence of the SARS-CoV-2 Omicron sublineages resulted in drastically increased transmission rates and reduced protection from vaccine-induced immunity. To counteract these effects, multiple booster strategies were used in different countries, although data comparing their efficiency in improving protective immunity remains sparse, especially among vulnerable populations, including older adults. The inactivated CoronaVac vaccine was among the most widely distributed worldwide, particularly in China, and South America. However, whether homologous versus heterologous booster doses in those fully vaccinated with CoronaVac induce distinct humoral responses and whether these responses vary across age groups remain unknown. We analyzed plasma antibody responses from CoronaVac-vaccinated younger or older individuals in central and south America that received a homologous CoronaVac or heterologous BNT162b2 or ChAdOx1 booster vaccines. We found that both IgG levels against SARS-CoV-2 spike or RBD, as well as neutralization titers against Omicron sublineages, were substantially reduced in participants that received homologous CoronaVac when compared to heterologous BNT162b2 or ChAdOx1 booster. This effect was specifically prominent in recipients older than 50 years of age. In this group, CoronaVac booster induced low virus-specific IgG levels and failed to elevate their neutralization titers against any omicron sublineage. Our results point to significant inefficiency in mounting protective anti-viral humoral immunity in those who were primed with CoronaVac followed by CoronaVac booster, particularly among older adults, urging a heterologous regimen in high-risk populations fully vaccinated with CoronaVac. One Sentence SummaryHomologous CoronaVac boosters do not improve neutralization responses against current VOCs in older adults in contrast to heterologous regimens.

Accelerated SARS-CoV-2 intrahost evolution leading to distinct genotypes during chronic infection

The chronic infection hypothesis for novel SARS-CoV-2 variant emergence is increasingly gaining credence following the appearance of Omicron. Here we investigate intrahost evolution and genetic diversity of lineage B.1.517 during a SARS-CoV-2 chronic infection lasting for 471 days (and still ongoing) with consistently recovered infectious virus and high viral loads. During the infection, we found an accelerated virus evolutionary rate translating to 35 nucleotide substitutions per year, approximately two-fold higher than the global SARS-CoV-2 evolutionary rate. This intrahost evolution led to the emergence and persistence of at least three genetically distinct genotypes suggesting the establishment of spatially structured viral populations continually reseeding different genotypes into the nasopharynx. Finally, using unique molecular indexes for accurate intrahost viral sequencing, we tracked the temporal dynamics of genetic diversity to identify advantageous mutations and highlight hallmark changes for chronic infection. Our findings demonstrate that untreated chronic infections accelerate SARS-CoV-2 evolution, ultimately providing opportunity for the emergence of genetically divergent and potentially highly transmissible variants as seen with Delta and Omicron.

Rapid emergence of SARS-CoV-2 Omicron variant is associated with an infection advantage over Delta in vaccinated persons

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continues to shape the coronavirus disease 2019 (Covid-19) pandemic. The detection and rapid spread of the SARS-CoV-2 Omicron variant (lineage B.1.1.529) in Botswana and South Africa became a global concern because it contained 15 mutations in the spike protein immunogenic receptor binding domain and was less neutralized by sera derived from vaccinees compared to the previously dominant Delta variant. To investigate if Omicron is more likely than Delta to cause infections in vaccinated persons, we analyzed 37,877 nasal swab PCR tests conducted from 12-26 December 2021 and calculated the test positivity rates for each variant by vaccination status. We found that the positivity rate among unvaccinated persons was higher for Delta (5.2%) than Omicron (4.5%). We found similar results in persons who received a single vaccine dose. Conversely, our results show that Omicron had higher positivity rates than Delta among those who received two doses within five months (Omicron = 4.7% vs. Delta = 2.6%), two doses more than five months ago (4.2% vs. 2.9%), and three vaccine doses (2.2% vs. 0.9%). Our estimates of Omicron positivity rates in persons receiving one or two vaccine doses were not significantly lower than unvaccinated persons but were 49.7% lower after three doses. In comparison, the reduction in Delta positivity rates from unvaccinated to 2 vaccine doses was 45.6-49.6% and to 3 vaccine doses was 83.2%. Despite the higher positivity rates for Omicron in vaccinated persons, we still found that 91.2% of the Omicron infections in our study occurred in persons who were eligible for 1 or more vaccine doses at the time of PCR testing. In conclusion, escape from vaccine-induced immunity likely contributed to the rapid rise in Omicron infections.

Ethnic Variations in Healthcare Service Utilization and Access in Vietnamese Mountainous Setting.

Evidence of health service use and access across different target groups is essential for policy development, health promotion, and promotion of equity in healthcare. This study aims to look at ethnic variations in health service use and access among residents in mountainous areas of Vietnam. A cross-sectional descriptive study was conducted on 321 adults from two mountainous communes in Bac Kan province. Healthcare service use and access were evaluated by using a structured questionnaire. Zero-inflated Poisson regression was used to examine the ethnic variations in the healthcare service use and access. Of 321 mountainous residents, 63.6% used health services in the previous 12 months, of which 24.9% respondents used inpatient services and 47.9% used outpatient services. The number of outpatient medical services used by the Tay participant was higher than that of the Kinh and other ethnic groups (p < 0.05). Multivariate regression results showed that compared to Kinh people, Tay people had a higher number of outpatient service use (Coef. = 0.25, p=0.04), while people in other ethnicities had a lower number of service use (Coef. = -0.64, p=0.01). Meanwhile, no difference was found among groups regarding the number of inpatient service use (p > 0.05). This study showed the ethnic differences in outpatient use of health services among communities living in the northern mountainous setting of Vietnam.

Effect of Magnetic Magnetite (Fe3O4) Nanoparticle Size on Arsenic (V) Removal from Water.

Magnetic magnetite (Fe3O4) nanoparticles with average sizes of 5.11, 10.53, and 14.76 nm were synthesized by the chemical co-precipitation method. The surface area of Fe3O4 nanoparticles (average size of 5.11 nm) had the largest value of 167 m²/g. The adsorption capacity for removing arsenic (As(V)) from water at 3 ppm concentration was investigated by atomic absorption spectroscopy. Results showed that the As(V) adsorption capacity of Fe3O4 was dependent on particle size. The maximum absorption efficiency (Hmax) reached 99.02%, the equilibrium time was 30 min; the maximum Langmuir isotherm adsorption capacity was 14.46 mg/g with Fe3O4 nanoparticle an average size of 5 nm. The results indicate that reducing the size of Fe3O4 nanoparticles is a promised way for As(V) ion removal from water and wastewater treatment.

Domain Structural Transition and Structural Heterogeneity in GeO2 Glass Under Densification.

The domain structural transition and structural heterogeneity (SH) in GeO2 glass at 300 K and pressures up to 100 GPa are studied by means of molecular dynamics (MD) simulation. The results demonstrate that the structure of GeO2 glass comprises domain D4, domain D5, or domain D6, which depends strongly on pressure, where domain Dx (x = 4, 5, or 6) is a cluster of connected GeO x units, in which all Ge atoms possess the same coordination number of x. In the range of 9-18 GPa, GeO2 glass undergoes a structural transformation from domain D4 to domain D6 via domain D5. Under densification, structural evolution occurs along with the O xx → O xy atom variation, which comprises the processes of both merging and splitting of domain Dx and the exchange of domain-boundary (DB) atoms. The densification leads to a decrease of the Voronoi polygon (VP) volume of atoms. We found that the coexistence of separate domain structures is the origin of spatial SH in GeO2 glass. Pressure-dependent structural heterogeneity in GeO2 glass is also discussed in detail.

Injectable Nanocomposite Hydrogels and Electrosprayed Nano(Micro)Particles for Biomedical Applications.

Polymeric scaffolds have played important roles in biomedical applications due to their potentially practical performance such as delivery of bioactive components and/or regenerative cells. These materials were well-designed to encapsulate bioactive molecules or/and nanoparticles for enhancing their performance in tissue regeneration and drug delivery systems. In the study, several multifunctional nanocomposite hydrogel and polymeric nano(micro)particles-electrosprayed platforms were described from their fabrication methods and structural characterizations to potential applications in the mentioned fields. Regarding to their described performance, these multifunctional nanocomposite biomaterials could pay many ways for further studies that enables them apply in clinical applications.

Recent Trends in Hydroxyapatite (HA) Synthesis and the Synthesis Report of Nanostructure HA by Hydrothermal Reaction.

This research summary the trend in synthesis of Hydroxyapatite (HA) using different route such as dry method and wet method (co-precipitation method; emulsion method, hydrolysis method, sol-gel method, hydrothermal method). In addition, the research group also report the technique to synthesis nano-structure HA by hydrothermal reaction using Ca(OH)2 and H3PO4 with the Ca/P molar ratio of 1.67. The mixture after homogenized for 2 h, follow by hydrothermal reaction at different hydrothermal temperature time (100 °C, 150 °C, and 180 °C) and different hydrothermal reaction time (0 h, 12 h and 24 h). The 180 °C-hydrothermal treated-HA has needle-like shape with the diameter of 10 ~ 20 nm and length of below 100 nm, which is similar with human bone. For the hydrothermal reaction, temperature is the key to form nanostructure HA.

Posterior nasal neurectomy in treatment of intractable rhinitis: A preliminary series

Objective@#To evaluate the efficacy and safety of posterior nasal neurectomy on the treatment of nasal congestion, rhinorrhea, sneezing, and post-nasal discharge in intractable rhinitis patients.@*Methods@#Design: Preliminary case series. Setting: Tertiary University Medical Center. Participant: Ten (10) patients with intractable rhinitis underwent endoscopic posterior nasal neurectomy in both sides. Symptoms were compared pre- and post-operatively one month and one year after surgery using Visual Analog Scale (VAS) scores. Endoscopic pre- and one-month post-operative Lund-Mackay scores were also compared.@*Results@#All four mean nasal symptom scores were reduced significantly at 1-month follow-up for nasal congestion (1.5 ± 1.08 vs 4.1 ± 0.5687, p = .00001), rhinorrhea (0.7 ± 0.823 vs 3.4 ± 0.966, p = .00001) post-nasal discharge (0.9 ± 0.994 vs 2.4 ± 1.5, p = .03), and sneezing (1.1 ± 0.738 vs 3 ± 0.943, p = .02). Mean endoscopic scores were also reduced significantly at one month, from 12.9 ± 2.55 to 4.2 ± 3, p = 0.0001.In the 6 patients that followed up at 1-year, post-operative mean nasal symptoms were still significantly better for congestion (0.6667 ± 0.8165 vs 4 ± 0.632, p = 0.00001), rhinorrhea (0.6667 ± 0.5164 vs 3.67 ± 1.033, p = .001), post-nasal discharge (0.1667 ± 0.40825 vs 2.17 ± 1.835, p = .033), sneezing (0.5 ± 0.54772 vs 3.17 ± 0.983, p = 0.0001). Mean post-operative VAS nasal scores and endoscopic scores were well associated (Correlation Coefficient -.648, p = .048).@*Conclusion@#Posterior nasal neurectomy could be considered as a safety and effective way to treat intractable rhinitis patients in Vietnam.