Immunogenicity and safety of heterologous versus homologous prime-boost schedules with inactivated and adenoviral vectored SARS-CoV-2 vaccines - A prospective multi-center study.

Background: During the peak of Coronavirus disease (COVID-19) pandemic in Thailand when the emergence of delta variant reduced the efficacy of inactivated vaccine, Thailand had abundance of inactivated vaccine but mRNA vaccine was not available and the supply of adenoviral-vectored vaccine was limited. The heterologous vaccination using CoronaVac and ChAdOx1-nCoV-19 vaccines was applied. We aim to compare the immunogenicity of immune response of primary vaccination with homologous ChAdOx1 nCoV-19 and heterologous vaccination with CoronaVac and ChAdOx1 nCoV-19. Methods: A total of 430 adults, scheduled to receive ChAdOx1-nCoV-19 as their second dose of primary COVID-19 vaccination, were enrolled. Participants were classified into two groups based on the first dose vaccine as CoronaVac (heterologous group) or ChAdOx1 nCoV-19 (homologous group). The primary outcome was antibodies to the SARS-CoV-2 spike protein receptor binding domain (anti-RBD) titres at 28 days after the second dose of vaccination. Secondary outcomes were anti-RBD titres at 90 days, surrogate viral neutralizing test (sVNT) at 28 and 90 days, and adverse events. Findings: In 358 participants with correct vaccine interval, the anti-RBD geometric mean titre ratio for the heterologous versus homologous group was 0.55 (95%CI; 0.44-0.067); p < 0.001 at day 28, and 0.80 (95%CI; 0.65-1.00); P = 0.05 at day 90. Median sVNT neutralizing activity was not significantly different in the heterologous versus homologous group at 28 days (93.5 vs 92.7 %); p = 0.13, but significantly higher in the heterologous group at day 90 (82.9 vs 76.4 %); p = 0.01. Interpretation: The homologous vaccination resulted in higher anti-RBD titres at 28 days after vaccination, but titres in the homologous group showed more rapid decline at 90 days. In the sVNT assay, median neutralization was similar at 28 days, but was longer-lasting and higher in the heterologous group at 90 days. Funding: This research received funding from the Royal College of Physicians of Thailand special grant 2021 for research initiative during COVID-19 pandemic.

Clinical Features of Cryptococcal Meningoencephalitis in HIV-Positive and -Negative Patients in a Resource-Limited Setting.

Cryptococcal meningoencephalitis is a systemic fungal infection in immunocompromised and immunocompetent individuals. This study investigated the clinical characteristics and factors associated with mortality in HIV-associated and non-HIV-associated cryptococcal meningoencephalitis in a resource-limited setting. This was a retrospective cohort study of patients with cryptococcal meningoencephalitis between January 2009 and December 2019 at a tertiary teaching hospital in Thailand. Overall, 1019 patients with cryptococcal meningoencephalitis were enrolled, and 923 (90.6%) were HIV-positive. The patients with HIV-associated cryptococcal meningoencephalitis were younger than the HIV-negative patients (37 versus 56 years, p < 0.01). The HIV-negative patients were more likely to have underlying conditions (52.1% versus 7.5%; p < 0.01), had a longer median duration of headaches prior to admission (14 days versus 6 days, p < 0.01), and were more likely to have an altered mental status at presentation (36.5% versus 18.6%, p < 0.01) and pulmonary involvement (15.6% versus 0.8%, p < 0.01). The HIV-positive patients had lower cerebrospinal fluid (CSF) white blood cell counts (4 versus 94 cells/mm3; p < 0.01), lower CSF protein (69 versus 157 mg/dL; p < 0.01), higher CSF glucose (38.8 versus 21 mg/dL; p < 0.01), and more frequent cryptococcemia (44.1% versus 20.5%; p < 0.01). The mortality rate was high but not significantly different between the two groups (30.2% versus 33.2%; p = 0.53). The HIV-positive patients with comorbidities, fever, an altered mental status at presentation, a CSF white blood cell count below 20 cell/mm3, fungemia, and positive CSF India ink were independently associated with 30-day mortality. In comparison, an altered mental status at presentation and fungemia were associated with 30-day mortality in HIV-negative patients. In conclusion, HIV-negative patients with cryptococcal meningoencephalitis had more extensive central nervous system inflammation, although the two groups' mortality rates were similar. Unfavorable prognostic factors included comorbidities, fever, an altered mental status at presentation, a low CSF white blood cell count, fungemia, and positive CSF India ink.

Streptococcus suis outbreak caused by an emerging zoonotic strain with acquired multi-drug resistance in Thailand.

Streptococcus suis is an emerging zoonotic swine pathogen which can cause severe infections in humans. In March 2021, an outbreak of S. suis infections with 19 confirmed cases of septicemia and meningitis leading to two deaths, occurred in Nakhon Ratchasima province, Thailand. We characterized the outbreak through an epidemiological investigation combined with Illumina and Nanopore whole genome sequencing (WGS). The source of the outbreak was traced back to a raw pork dish prepared from a single pig during a Buddhist ceremony attended by 241 people. WGS analysis revealed that a single S. suis serotype 2 strain belonging to a novel sequence type (ST) of the emergent Thai zoonotic clade CC233/379, was responsible for the infections. The outbreak clone grouped together with other Thai zoonotic strains from CC233/379 and CC104 in a global S. suis phylogeny and capsule switching events between serotype 2 zoonotic strains and serotype 7 porcine strains were identified. The outbreak strain showed reduced susceptibility to penicillin corresponding with mutations in key residues in the penicillin binding proteins (PBPs). Furthermore, the outbreak strain was resistant to tetracycline, erythromycin, clindamycin, linezolid and chloramphenicol, having acquired an integrative and conjugative element (ICE) carrying resistance genes tetO and ermB, as well as a transposon from the IS1216 family carrying optrA and ermA. This investigation demonstrates that multi-drug resistant zoonotic lineages of S. suis which pose a threat to human health continue to emerge.

Pneumococcal carriage among high-risk adults in a country with nonmandatory pneumococcal vaccination during the coronavirus disease 2019 pandemic.

BACKGROUND: Streptococcus pneumoniae carriage is a prerequisite for clinical infections and is used to make public health decisions on vaccine licensure. Pneumococcal carriage data among high-risk Thai adults are needed before national vaccine program introduction. The association between coronavirus disease 2019 (COVID-19) and pneumococcal carriage were also investigated. METHODS: During the COVID-19 pandemic, a multi-center cross-sectional study was conducted among high-risk Thai adults from September 2021 to November 2022. Pneumococcal carriage and serotypes were investigated using both conventional and molecular methods. Demographics and co-morbidities were determined for carriage while accounting for case clustering from various study sites. RESULTS: A total of 370 individuals were enrolled. The prevalence of pneumococcal carriage, as determined by the molecular method, was 30.8 % (95 % confidence interval (CI): 26.1-35.8), while after excluding non-typeable pneumococci from the oropharyngeal sample, the carriage prevalence was 20.8 % (95 % CI: 16.79-25.31). The serotype coverage rates by pneumococcal vaccine were 12.3 %, 13.1 %, and 16.4 % for PCV13, PCV15 or PCV20, and PPSV23, respectively, while the non-vaccine type was the majority (45.1 %). The most common serotype was 19B/C (35.5 %), followed by 6 A/B/C/D (10.7 %). The age group under 65 years was associated with a higher pneumococcal carriage rate than the age group 85 and older (odds ratio (OR): 5.01, 95 % CI: 1.75-14.36). There was no significant difference between SARS-CoV-2 and carriage status. CONCLUSIONS: The prevalence of pneumococcal carriage in Thais was high. The majority of serotypes were not covered by the vaccine. Further studies on the link between carriage serotypes and disease are required. The magnitude and serotype distribution of carriage were comparable in the SARS-CoV-2 positive and negative groups.

Francisella sp., a Close Relative of Francisella orientalis, Causing Septicemia with Cholestatic Hepatitis in a Patient with Anti-Interferon-γ (IFN-γ) Autoantibodies.

Francisella is an intracellular, fastidious, Gram-negative bacterium that is difficult to identify using routine microbiological methods in the laboratory. We studied the isolation of Francisella sp. (strain IDAMR664) from the blood of a patient with anti-interferon-γ (IFN-γ) autoantibodies who presented with septicemia and cholestatic hepatitis. Analysis of the strain IDAMR664 genome sequence revealed the isolate was closely related to the strain GA01-2794 that had been isolated from a human in the USA. In addition, it was clustered with F. orientalis, a fish pathogen. The isolate contained several virulence factors and had Francisella pathogenicity island pattern no. 3.

Efficacy and Safety of Immunomodulators in Patients with COVID-19: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.

INTRODUCTION: Many immunomodulators have been studied in clinical trials for the treatment of coronavirus disease 2019 (COVID-19). However, data identifying the most effective and safest treatment are lacking. We conducted a systematic review and network meta-analysis to rank immunomodulators in the treatment of COVID-19 according to their efficacy and safety. METHODS: Published and peer-reviewed randomized controlled trials assessing the efficacy of immunomodulators in hospitalized patients with COVID-19 were searched up to June 30, 2021. Direct and network meta-analyses were applied to assess the outcomes. The probability of efficacy and safety was estimated, and the drugs were awarded a numerical ranking. RESULTS: Twenty-six studies were eligible. Compared with standard of care, dexamethasone and tocilizumab had significantly lower mortality rates with pooled risk ratios (RRs) of 0.91 (95% confidence interval [CI] 0.84-0.99) and 0.88 (95% CI 0.82-0.96), respectively. Meanwhile, the most effective corticosteroid, interleukin-6 antagonist, and Janus kinase (JAK) inhibitor were hydrocortisone, sarilumab, and ruxolitinib, respectively. However, when superimposed infection was considered, ruxolitinib was the best treatment followed by baricitinib. Moreover, methylprednisolone had the worst combined efficacy and safety among the examined treatments. CONCLUSIONS: Overall, immunomodulators were more effective than standard of care. Important differences exist among immunomodulators regarding both efficacy and safety in favor of ruxolitinib and baricitinib. Further well-conducted randomized controlled trials should focus on JAK inhibitors. Methylprednisolone use should be discouraged because of its poor efficacy and high risk of superimposed infection. TRIAL REGISTRATION: PROSPERO registration identifier CRD 42021257421.