Immunogenicity and reactogenicity of accelerated regimens of fractional intradermal COVID-19 vaccinations

IntroductionThis phase I study explored the immunogenicity and reactogenicity of accelerated, Q7 fractional, intradermal vaccination regimens for COVID-19.MethodsParticipants (n = 60) aged 18-60 years, naïve to SARS-CoV-2 infection or vaccination, were randomly allocated into one of four homologous or heterologous accelerated two-dose, two-injection intradermal regimens seven days apart:(1) BNT162b2-BNT162b2(n= 20),(2) ChAdOx1- BNT162b2 (n = 20), (3) CoronaVac-ChAdOx1 (n = 10), and (4) ChAdOx1-ChAdOx1 (n = 10). CoronaVac and ChAdOx1 were 20%, and BNT162b2 17%, of their standard intramuscular doses (0.1 mL and 0.05 mL per injection, respectively). Humoral immune responses were measured through IgG response towards receptor binding domains (RBD-IgG) of ancestral SARS-CoV-2 spike protein and pseudovirus neutralization tests (PVNT50). Cellular immune responses were measured using ELISpot for ancestral protein pools.ResultsImmunogenicity was highest in regimen (2), followed by (1), (4), and (3) 2 weeks after the second dose (P < 0.001 for anti-RBD-IgG and P= 0.01 for PVNT50). Each group had significantly lower anti-RBD IgG (by factors of 5.4, 3.6, 11.6, and 2.0 for regimens (1) to (4), respectively) compared to their respective standard intramuscular regimens (P < 0.001 for each). Seroconversion rates for PVNT50 against the ancestral strain were 75%, 90%, 57% and 37% for regimens (1) to (4), respectively. All participants elicited ELISpot response to S-protein after vaccination. Adverse events were reportedly mild or moderate across cohorts.DiscussionWe concluded that accelerated, fractional, heterologous or homologous intradermal vaccination regimens of BNT162b2 and ChAdOx1 were well tolerated, provided rapid immune priming against SARS-CoV-2, and may prove useful for containing future outbreaks

Molecular and Antifilarial IgG4 Detection Using the miniPCR-Duplex Lateral Flow Dipstick and BmSxp-ELISA in Myanmar Immigrant Communities

Lymphatic filariasis (LF) is an important tropical disease that affects over a billion people in more than 80 countries and approximately 40 million people are currently suffering from severe disfigurement and disability. A diagnostic tool is the principal impact factor to determine the infection status of lymphatic filariasis. The purpose of the present study was to investigate nucleic acid of Wuchereria bancrofti as well as antifilarial IgG4 in a Myanmar immigrant community living along the Moei River, a natural border between Mae Sot, Tak province Thailand and Myawaddy, Myanmar which is an endemic area of bancroftian filariasis. Blood was collected from 300 Myanmar immigrants in Mae Sot district, Tak Province. The nucleic acid of W. bancrofti was assessed in the study population using our recent published miniPCR-Duplex Lateral Flow dipstick (DLFD) platform as well as the standard PCR technique. The antifilarial IgG4 was detected in the study population using the developed ELISA which used BmSxp protein as antigen. The miniPCR-DLFD method delivered results comparable to the standard PCR technique and it enables convenient and rapid visual detection of the parasite nucleic acid. Furthermore, the ELISA using BmSxp antigen demonstrated a sensitivity, specificity, and positive and negative predictive values of 98.1%, 98.9%, 96.3%, and 99.4% respectively. The W. bancrofti nucleic acid and antifilarial IgG4 were detected in 1.6% (5/300), and 2% (6/300) of the study population, accordingly. The results of this study also revealed important epidemiological data about LF on the Thai–Myanmar border

Distinct roles for nitric oxide in resistant C57BL/6 and susceptible BALB/c mice to control <it>Burkholderia pseudomallei </it>infection

Abstract Background Burkholderia pseudomallei is the causative agent of melioidosis, an emerging bacterial infectious disease in tropical and subtropical areas. We recently showed that NADPH oxidase but not nitric oxide (NO) contributes to resistance in innately resistant C57BL/6 mice in a B. pseudomallei respiratory infection model. However, the function of NO for resistance was shown to differ among distinct strains of mice and proved also to be stage dependent in various infection models. The present study therefore aimed to examine the role of NO in a systemic infection model of melioidosis and to test whether the function of NO differs among innately resistant C57BL/6 and susceptible BALB/c mice after B. pseudomallei infection. Results C57BL/6 iNOS-/- mice that were intravenously infected with B. pseudomallei survived several weeks, whereas most of the wild type animals succumbed during this period. The bacterial burden in liver and spleen was significantly higher in wild type animals compared to iNOS-/- mice 13 days after challenge. In contrast, BALB/c mice that were treated with amminoguanidine to inhibit NO expression in vivo showed significantly enhanced mortality rates and higher bacterial loads in liver and spleen compared to control animals. The bactericidal function of IFN-γ stimulated C57BL/6 iNOS-/- macrophages were not altered after B. pseudomallei infection, but BALB/c macrophages exhibited reduced killing activity against the pathogen when NO was inhibited. Conclusion Our present data indicate a dual role of NO among resistant and susceptible mouse strains after B. pseudomallei infection. NO mediated mechanisms are an essential component to control the infection in susceptible BALB/c mice. In contrast, NO production in B. pseudomallei infected C57BL/6 mice rather harmed the host likely due to its detrimental effects.</p

Caspase-1 Mediates Resistance in Murine Melioidosis▿

The gram-negative rod Burkholderia pseudomallei is the causative agent of melioidosis, a potentially fatal disease which is endemic in tropical and subtropical areas. The bacterium multiplies intracellularly within the cytosol, induces the formation of actin tails, and can spread directly from cell to cell. Recently, it has been shown that B. pseudomallei can induce caspase-1-dependent cell death in macrophages. The aim of the present study was to further elucidate the role of caspase-1 during B. pseudomallei infection. In vivo experiments with caspase-1−/− mice revealed a high susceptibility to B. pseudomallei challenge. This phenotype was associated with a significantly higher bacterial burden 2 days after infection and decreased gamma interferon (IFN-γ) and interleukin-18 cytokine levels 24 h after infection compared to control animals. caspase-1−/− bone marrow-derived macrophages (BMM) exhibited strong caspase-3 expression and reduced cell damage compared to wild-type (WT) cells during early B. pseudomallei infection, indicating “classical” apoptosis, whereas WT BMM showed signs of rapid caspase-1-dependent cell death. Moreover, we found that caspase-1−/− BMM had a strongly increased bacterial burden compared to WT cells 3 h after infection under conditions where no difference in cell death could be observed between both cell populations at this time point. We therefore suggest that caspase-1-dependent rapid cell death might contribute to resistance by reducing the intracellular niche for B. pseudomallei, but, in addition, caspase-1 might also have a role in controlling intracellular replication of B. pseudomallei in macrophages. Moreover, caspase-1-dependent IFN-γ production is likely to contribute to resistance in murine melioidosis

Immunogenicity and reactogenicity against the SARS-CoV-2 variants following heterologous primary series involving CoronaVac, ChAdox1 nCov-19 and BNT162b2 plus BNT162b2 booster vaccination: An open-label randomized study in healthy Thai adults

We evaluated the immunogenicity and reactogenicity of heterologous COVID-19 primary schedules involving BNT162b2 (Pfizer-BioNTech), ChAdOx1 nCoV-19 (AstraZeneca) and CoronaVac (Sinovac) in healthy adults, as well as booster response to BNT162b2 following heterologous CoronaVac and ChAdOx1 nCoV-19 regimens. Participants were randomized to one of seven groups that received two-dose homologous BNT162b2 or heterologous combinations of CoronaVac, ChAdOx1 nCoV-19 and BNT162b2, with 4 weeks interval. A total of 210 participants were enrolled, 30 in each group. Median age of participants was 38 (19–60) years, and 108/210 (51.43%) were female. Overall adverse events after the second dose were mild to moderate. We found that groups that received BNT162b2 as second dose induced the highest anti-receptor binding domain IgG response against the ancestral strain [BNT162b2: geometric mean concentration (GMC) 2133–2249 BAU/mL; ChAdOx1 nCoV-19: 851–1201; CoronaVac: 137–225 BAU/mL], neutralizing antibodies (NAb) against Beta and Delta, and interferon gamma response. All groups induced low to negligible NAb against Omicron after second dose. A BNT162b2 booster (third dose) following heterologous CoronaVac and ChAdOx1 nCoV-19 regimens induced >140-fold increase in NAb titers against Omicron. Our findings indicate that heterologous regimens using BNT162b2 as the second dose may be an alternative schedule to maximize immune response. While heterologous two-dose schedules induced low NAb against Omicron, the use of an mRNA vaccine booster dose substantially increased the Omicron response. These findings are relevant for low-income countries considering heterologous primary and booster COVID-19 vaccine schedules

Characterization of limbal explant sites: Optimization of stem cell outgrowth in in vitro culture.

Simple limbal epithelial transplantation (SLET) and cultivated limbal epithelial transplantation (CLET) are proven techniques for treating limbal stem cell deficiency (LSCD). However, the precise regions that are most suitable for preparing explants for transplantation have not been identified conclusively. Accordingly, this in vitro study aimed at determining ideal sites to be selected for tissue harvest for limbal stem cell culture and transplantation. We evaluated cell outgrowth potential and the expression of stem cell markers in cultures from 48 limbal explants from five cadaveric donors. The limbal explants were generated from the three specific sites: Lcor (located innermost and adjacent to the cornea), Lm (middle limbus), and Lconj (located outermost adjacent to the conjunctiva). We found that explants from the Lconj and Lm sites exhibited higher growth potential than those from the Lcor site. Transcript encoding the stem cell marker and p63 isoform, ΔNp63, was detected in cells from Lm and Lconj explants; expression levels were slightly, though significantly (p-value < 0.05), higher in Lm than in Lconj, although expression of ΔNp63α protein was similar in cells from all explants. Differential expression of ATP-Binding Cassette Subfamily G Member 2 (ABCG2) did not reach statistical significance. Immunohistochemistry by indirect immunofluorescence analysis of limbus tissue revealed that the basal layer in explant tissue from Lconj and Lm contained markedly more stem cells than found in Lcor explant tissue; these findings correlate with a higher capacity for growth. Collectively, our findings suggest that explants from the Lconj and Lm sites should be selected for limbal cell expansion for both CLET and SLET procedures. These new insights may guide surgeons toward specific limbal sites that are most suitable for stem cell culture and transplantation and may ultimately improve treatment outcomes in the patients with LSCD

Effectiveness of Integrated Care on Delaying Progression of stage 3-4 Chronic Kidney Disease in Rural Communities of Thailand (ESCORT study): a cluster randomized controlled trial

Background: In developing countries, renal specialists are scarce and physician-to-patient contact time is limited. While conventional hospital-based, physician-oriented approach has been the main focus of chronic kidney disease (CKD) care, a comprehensive multidisciplinary health care program (Integrated CKD Care) has been introduced as an alternate intervention to delay CKD progression in a community population. The main objective is to assess effectiveness of Integrated CKD Care in delaying CKD progression. Methods: We carried out a community-based, cluster randomized controlled trial. Four hundred forty-two stage 3-4 CKD patients were enrolled. In addition to the standard treatments provided to both groups, the patients in the intervention group also received “Integrated CKD Care”. This was delivered by a multidisciplinary team of hospital staff in conjunction with a community CKD care network (subdistrict healthcare officers and village health volunteers) to provide group counseling during each hospital visit and quarterly home visits to monitor compliance with the treatment. Duration of the study was 2 years. The primary outcome was difference of mean eGFR between the intervention and the control groups over the study period. Results: The mean difference of eGFR over time in the intervention group was significantly lower than the control group by 2.74 ml/min/1.73 m2 (95%CI 0.60–4.50, p = 0.009). Seventy composite clinical endpoints were reported during the study period with significantly different incidences between the control and the intervention groups (119.1 versus 69.4 per 1000 person-years; hazard ratio (HR) 0.59, 95% CI 0.4–0.9, p = 0.03). Conclusion: Integrated CKD Care can delay CKD progression in resource-limited settings. Trial registration (NCT01978951). Prospectively registered as of December 8, 2012

Orientia tsutsugamushi, agent of scrub typhus, displays a single metapopulation with maintenance of ancestral haplotypes throughout continental South East Asia

International audienceOrientia tsutsugamushi is the causative agent of scrub typhus, a major cause of febrile illness in rural area of Asia-Pacific region. A multi-locus sequence typing (MLST) analysis was performed on strains isolated from human patients from 3 countries in Southeast Asia: Cambodia, Vietnam and Thailand. The phylogeny of the 56-kDa protein encoding gene was analyzed on the same strains and showed a structured topology with genetically distinct clusters. MLST analysis did not lead to the same conclusion. DNA polymorphism and phylogeny of individual gene loci indicated a significant level of recombination and genetic diversity whereas the ST distribution indicated the presence of isolated patches. No correlation was found with the geographic origin. This work suggests that weak divergence in core genome and ancestral haplotypes are maintained by permanent recombination in mites while the 56-kDa protein gene is diverging in higher speed due to selection by the mammalian immune system