Reactogenicity and persistence of IgG antibodies against SARS-CoV-2 among recipients of ChAdOx1 nCoV-19 vaccine: A single center experience from Sri Lanka.

Objectives: Actual world data on vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are imperative for future immunization decisions. We studied the reactogenicity and IgG response in a cohort dually vaccinated with the ChAdOx1 nCoV-19 vaccine. Methods: This prospective study recruited 494 ChAdOx1 nCoV-19 vaccine recipients at the University Hospital KDU between January 30 and February 5, 2021, and followed up for 9 months. The two doses of the vaccine were administered 3-month apart, followed by a booster dose with the BNT162b2 (Pfizer-BioNTech) vaccine 6 months later. One-week post-vaccination surveillance ascertained the reactogenicity of the vaccine. Seroprevalence of IgG antibodies before each vaccination dose was determined using a commercially available quantitative ELISA kit (WANTAI SARS-CoV-2 IgG Quantitative ELISA Beijing China). Reactogenicity profiles after vaccination doses were compared. Association of pre-vaccination seropositivity and demographic variables with antibody levels was assessed. Results: Reactogenicity was reported by 78.5% (329/419) and 25.4% (104/410) participants after the first and second doses, respectively, with a significantly high mean total score of vaccine-related symptoms following the first dose (P = 0.015). Post-first dose seroconversion rate was 97.1%, and the immune response was more robust among pre-vaccination seropositive participants and females. Following the second dose, 100% seroconversion was observed. Subgroup analysis of 196 participants revealed persistent antibodies at nine months with a rise in the previously measured levels among 78.1% compared to 21.9% with declining titers. Antibody waning was significantly associated with pre-vaccination seropositivity (P = 0.015) and female gender (P = 0.022). Conclusions: High seroconversion rates and longevity of antibody response in the absence of serious concerns regarding reactogenicity suggest that the vaccine is immunogenic and safe. Significant antibody waning among females and pre-vaccination seropositive participants warrant further research.

Fosfomycin: A potential oral option for treatment of urinary tract infections in Sri Lanka in the context of high antibiotic resistance.

Introduction: Fosfomycin is an effective treatment for urinary tract infections (UTIs). It is not currently used in Sri Lanka to treat UTIs. Hence, this study was conducted to assess the fosfomycin susceptibility for E. coli in urinary isolates, with an aim to find the usability of fosfomycin in the context of high antibiotic resistance. Methods: E. coli isolates were identified by the colony appearance and by performing biochemical tests for the urinary coliform isolates collected from two different hospitals in Western Province Sri Lanka, during the period of November 2021 to February 2022. Susceptibility to fosfomycin 200 µg disc was performed following the Clinical Laboratory Standard Institute (CLSI) disc diffusion method. Results: A total of 101 E. coli isolates from both oncology patients (52.5%) and non-oncology patients (47.5%) were identified and included in the study. The study sample showed majority of females (63.3%). Ampicillin showed the highest resistance rate (72.2%) while fosfomycin was the only antibiotic that showed 100% in vitro susceptibility to all the tested clinical isolates. The overall presence of multidrug-resistant (MDR) and carbapenem-resistant (CR) E. coli were 47.5% and 9.9% respectively. Conclusions: Fosfomycin is a potential antibiotic option especially for MDR and CR organisms, with 100% in vitro susceptibility. Further studies involving multiple centers, with larger sample size and clinical efficacy studies would be important to assess the potential use of fosfomycin especially for the treatment of UTI-causing MDR and CR organisms.

Diagnostic utility and validation of a newly developed real time loop mediated isothermal amplification method for the detection of SARS CoV-2 infection.

Background: Detecting SARS-CoV-2 using a simple real time molecular assay will be helpful for the mitigation efforts in low / middle income countries during the pandemic. We have developed and validated a rapid and simple real time loop mediated isothermal amplification assay (LAMP) for screening of SARS-CoV-2 infection in known infected and non-infected individuals. Methods: Six sets of primers were designed targeting the N-gene of the SARS-CoV-2 (Accession ID MN994468). LAMP reactions were performed using Warm Start 2X Master Mix and real-time PCR machine at 65 °C for 60 cycles with 15 s for each cycle. Results were read by visualizing turbidity under ultraviolet light and real time fluorescence detection through FAM channel of the real time PCR machine. We tested a total of 320 including 240 SARS CoV-2 positive (Ct values <40) and 80 SARS CoV-2 negative samples as tested by a real time RT-PCR using the newly developed LAMP assay. Results: A total of 206 out of 240 SARS CoV-2 positive samples were tested positive by the newly developed LAMP assay with a sensitivity of 86%. All 80 SARS CoV-2 negative samples were tested negative by the newly developed LAMP assay with a specificity of 100%. Conclusion: The newly developed real time LAMP assay has a sensitivity of 86% and specificity of 100% compared to the real time RT-PCR for the detection of SARS CoV-2. The new assay will be useful to screen large number of samples if adopted to minimize the time and cost.

Elevation in liver enzymes is associated with increased IL-2 and predicts severe outcomes in clinically apparent dengue virus infection.

The objective of the present study was to assess the circulating TNF-α and IL-2 levels in dengue virus (DENV) infected patients and to correlate these with clinical severity of DENV infections. A single analyte quantitative immunoassay was used to detect TNF-α and IL-2 in 24 dengue fever (DF) and 43 dengue haemorrhagic fever (DHF) patients, 15 healthy adults and 6 typhoid patients. The mean TNF-α and IL-2 levels of DENV- infected patients were higher than that of healthy adults and typhoid patients. No significant difference in TNF-α levels was noted between DF and DHF patients (p=0.5) but a significant increase in IL-2 levels was observed in DHF compared with DF patients (mean of DF=59.7pg/mL, mean of DHF=166.9pg/mL; p=0.02). No significant association of TNF-α or IL-2 levels was noted with packed cell volume (>45), thrombocytopenia, leucopenia or the presence of viraemia. The liver function tests measuring AST (aspartate aminotransferase) (p=0.01) and ALT (alanine aminotransferase) (p=0.02) levels were significantly elevated in DENV-infected patients. AST:ALT was significantly elevated in DHF/DSS (dengue shock syndrome) compared with DF patients. A significant positive linear correlation was noted between AST and IL-2 (r=0.31; p=0.01) and ALT and IL-2 elevations (r=0.2; p=0.02). Thus, AST and ALT levels correlate with both disease severity and circulating IL-2 levels. We suggest a role for circulating IL-2 in liver dysfunction and propose that a combined assessment of AST/ALT in conjunction with IL-2 at the early stages of symptomatic DENV infection may be useful to predict the severe forms of dengue.

Characterization of dengue virus infections in a sample of patients suggests unique clinical, immunological, and virological profiles that impact on the diagnosis of dengue and dengue hemorrhagic fever.

Dengue virus (DENV) infections are increasing with respect to incidence and severity in the Central Province of Sri Lanka. The objective of this study was to define the clinical, immunological, and virological profiles of patients admitted to the General Hospital, Kandy with clinically apparent dengue. Demographic, clinical, hematological parameters, liver enzymes (ALT and AST), and blood samples were collected from 292 patients with fever <5 days post onset and fulfilling the WHO criteria for the diagnosis of dengue fever/dengue hemorrhagic fever (DF/DHF). Samples were analyzed for, anti-DENV IgM, IgG, and DENV nucleic acid. Myalgia was the commonest complaint by 65% of the patients. Packed cell volume was >45% in 27% of the patients while 42.12% had reduced platelets and 62.67% had reduced white blood cell counts. In contrast to other studies, positive tourniquet test (PTT) and petechiae were not major indicators of DENV infection or severity of the disease. Clinical profiles were significantly different between DF and DHF/DSS and showed many similarities to that reported elsewhere. Altogether, 43 patients (14.73%) were viremic as detected by RT-PCR; 181 patients (62%) were positive for anti-DENV IgM, and 245 (84%) patients were positive for anti-DENV IgG. In combination, anti-DENV IgM and RT-PCR assays detected 224 (77.5%) of DENV infected cases, thus improving the DENV diagnosis rate. Hence, the diagnostic utility of PTT, anti-DENV IgM/IgG serology, or RT-PCR used alone in the early phase of illness is low in Sri Lanka but the diagnostic value can be improved by a combination of serology and RT-PCR. J. Med. Virol. 88:1703-1710, 2016. © 2016 Wiley Periodicals, Inc.

Diagnosis of dengue in Sri Lanka: improvements to the existing state of the art in the island.

Dengue fever (DF) is a mosquito borne virus infection which is endemic to the tropical regions of the world. In Sri Lanka, the first sero-positive case was reported in the 1960s; since then the island has experienced several outbreaks of DF/dengue haemorrhagic fever (DHF). The disease is more prevalent in some parts of the country where rapid urbanisation has taken place. Diagnosis of DF/DHF is mainly done using the clinical features only due to the unavailability of laboratory diagnosis in many parts of the country and this might lead to over or under diagnosis of the disease. A rational diagnostic approach which combines the history and clinical profiles together with specific virological laboratory data would help in the correct identification of the disease. Furthermore, a feasible algorithm for the laboratory diagnosis of dengue will help to confirm the cases with a high level of clinical suspicion. This would then facilitate the notification of correctly identified cases to the public health authorities to assess the dengue burden. The scope of this review is to improve the existing laboratory diagnosis of DF/DHF by proposing a feasible algorithm to implement in Sri Lanka that would enable better detection of cases.

Leptospirosis outbreak in Sri Lanka in 2008: lessons for assessing the global burden of disease.

Global leptospirosis disease burden estimates are hampered by the lack of scientifically sound data from countries with probable high endemicity and limited diagnostic capacities. We describe the seroepidemiologic and clinical characteristics of the leptospirosis outbreak in 2008 in Sri Lanka. Definitive/presumptive case definitions proposed by the World Health Organization Leptospirosis Epidemiology Reference Group were used for case confirmation. Of the 404 possible cases, 155 were confirmed to have leptospirosis. Highest titers of patient seum samples reacted with serovars Pyrogenes (28.7%), Hardjo (18.8%), Javanica (11.5%), and Hebdomadis (11.5%). Sequencing of the 16S ribosomal DNA gene identified six infections: five with Leptospira interrogans and one with L. weilli. In this patient population, acute renal failure was the main complication (14.8%), followed by myocarditis (7.1%) and heart failure (3.9%). The case-fatality rate was 1.3%. This report strengthens the urgent need for increasing laboratory diagnostic capabilities to determine the causes of epidemic and endemic infectious diseases in Sri Lanka, a finding relevant to other tropical regions.