Anchalee Tungtrongchitr

Many patients develop post-acute COVID syndrome (long COVID (LC)). We compared the immune response of LC and individuals with post-COVID full recovery (HC) during the Omicron pandemic. Two hundred ninety-two patients with confirmed COVID infections from January to May 2022 were enrolled. We observed anti-SARS-CoV-2 receptor-binding domain immunoglobulin G, surrogate virus neutralization test, T cell subsets, and neutralizing antibodies against Wuhan, BA.1, and BA.5 viruses (NeuT). NeuT was markedly reduced against BA.1 and BA.5 in HC and LC groups, while antibodies were more sustained with three doses and an updated booster shot than ≤2-dose vaccinations. The viral neutralization ability declined at >84-days after COVID-19 onset (PC) in both groups. PD1-expressed central and effector memory CD4⁺ T cells, and central memory CD8⁺ T cells were reduced in the first months PC in LC. Therefore, booster vaccines may be required sooner after the most recent infection to rescue T cell function for people with symptomatic LC.

Angiostrongylus cantonensis is the major etiological nematode parasite causing eosinophilic meningitis and/or eosinophilic meningoencephalitis in humans. The rapid global spread of Angiostrongylus cantonensis and the emerging occurrence of the infection have exposed the shortcomings of traditional/conventional diagnostics. This has spurred efforts to develop faster, simpler and more scalable platforms that can be decentralized for point-of-need laboratory testing. By far, the point-of-care immunoassays such as the lateral flow assay (LFA) are the best-placed. In this work, a LFA in the form of an immunochromatographic test device (designated AcAgQuick^Dx), based on the detection of a circulating Angiostrongylus cantonensis-derived antigen, was established using anti-31 kDa Angiostrongylus cantonensis antibody as the capture reagent and anti-Angiostrongylus cantonensis polyclonal antibody as the indicator reagent. The AcAgQuick^Dx was evaluated for its diagnostic potential with a total of 20 cerebrospinal fluids (CSF) and 105 serum samples from patients with angiostrongyliasis and other clinically related parasitic diseases, as well as serum samples from normal healthy subjects. Three of the ten CSF samples from serologically confirmed angiostrongyliasis cases and two of the five suspected cases with negative anti-Angiostrongylus cantonensis antibodies showed a positive AcAgQuick^Dx reaction. Likewise, the AcAgQuick^Dx was able to detect Angiostrongylus cantonensis specific antigens in four serum samples of the 27 serologically confirmed angiostrongyliasis cases. No positive reaction by AcAgQuick^Dx was observed in any of the CSF (n = 5) and serum (n = 43) samples with other parasitic infections, or the normal healthy controls (n = 35). The AcAgQuick^Dx enabled the rapid detection of active/acute Angiostrongylus cantonensis infection. It is easy to use, can be transported at room temperature and does not require refrigeration for long-term stability over a wide range of climate. It can supplement existing diagnostic tests for neuroangiostrongyliasis under clinical or field environments, particularly in remote and resource-poor areas.

The dynamics of humoral immune responses of patients after SARS-CoV-2 infection is unclear. This study prospectively observed changes in anti-receptor binding domain immunoglobulin G (anti-RBD IgG) and neutralizing antibodies against the Wuhan and Delta strains at 1, 3, and 6 months postinfection between October 2021 and May 2022. Demographic data, clinical characteristics, baseline parameters, and blood samples of participants were collected. Of 5059 SARS-CoV-2 infected adult patients, only 600 underwent assessment at least once between 3 and 6 months after symptom onset. Patients were categorized as immunocompetent (n = 566), immunocompromised (n = 14), or reinfected (n = 20). A booster dose of a COVID-19 vaccine was strongly associated with maintained or increased COVID-19 antibody levels. The booster dose was also more strongly associated with antibody responses than the primary vaccination series. Among patients receiving a booster dose of a mRNA vaccine or a heterologous regimen, antibody levels remained steady or even increased for 3 to 6 months after symptom onset compared with inactivated or viral vector vaccines. There was a strong correlation between anti-RBD IgG and neutralizing antibodies against the Delta variant. This study is relevant to resource-limited countries for administering COVID-19 vaccines 3 to 6 months after infection.

Background: Blomia ( B. ) tropicalis , as an important species of house dust mites (HDMs), plays a critical role in allergic diseases in tropical populations, but its allergen components are less investigated than those of other HDMs. Multiple omics methods have largely improved the identification of mite allergens. Here, we sought to identify a comprehensive allergen profile of B. tropicalis and advance the allergen component-resolved diagnosis (CRD) of mite allergy. Methods: Reference mite allergen sequences were searched in a high-quality genome of B. tropicalis . Comparative analysis was performed for important allergen groups. ELISA was used to assess the allergenicities of recombinant proteins of specific allergens. Results: A complete allergen profile of B. tropicalis was revealed, including thirty-seven allergen groups (up to Blo t 42). In-depth comparative analysis not only determined the homology of major allergen groups 5 and 21 but also shed light on the emergence and divergence of chitin-binding allergens. The specific Blo t 12 was identified to be a chitin-binding protein originating from the chitinase of allergen group 15. Immunoassays of recombinant proteins verified three novel allergens and the ELISA results suggested geographical differences in the B. tropicalis sensitization rate. Conclusions: The comprehensive allergen profile revealed in B. tropicalis , the comparative analysis of allergen groups and the immunoassay assessment of recombinant proteins largely expanded our knowledge to B. tropicalis allergens and could ultimately benefit the CRD of HDM allergy.

This study aimed to evaluate the efficacy of early antiviral treatment in preventing clinical deterioration in asymptomatic or mildly symptomatic severe acute respiratory syndrome coronavirus 2 infected (COVID-19) patients in home isolation and to share our experiences with the ambulatory management of nonsevere COVID-19 patients. This retrospective study included mild COVID-19 adult patients confirmed by real-time reverse transcription-polymerase chain reaction. They received care via an ambulatory management strategy between July 2021 and November 2021. Demographic data, clinical progression, and outcomes were collected. Both descriptive and inferential statistics were performed to illustrate the cohort’s characteristic and outcomes of the study. Univariable and multivariable logistic regression models were employed to investigate the associations between clinical factors and disease progression. A total of 1940 patients in the Siriraj home isolation system met the inclusion criteria. Their mean age was 42.1 ± 14.9 years, with 14.2% older than 60 years, 54.3% female, and 7.1% with a body weight ≥ 90 kg. Only 115 patients (5.9%) had deterioration of clinical symptoms. Two-thirds of these could be managed at home by dexamethasone treatment under physician supervision; however, 38 of the 115 patients (2.0% of the study cohort) needed hospitalization. Early favipiravir outpatient treatment (≤ 5 days from onset of symptoms) in nonsevere COVID-19 patients was significantly associated with a lower rate of symptom deterioration than late favipiravir treatment (50 [4.6%] vs 65 [7.5%] patients, respectively; P = .008; odds ratio 1.669; 95% confidence interval, 1.141–2.441). The unfavorable prognostic factors for symptom deterioration were advanced age, body weight ≥ 90 kg, unvaccinated status, higher reverse transcription-polymerase chain reaction cycle threshold, and late favipiravir treatment. The early delivery of essential treatment, including antiviral and supervisory dexamethasone, to ambulatory nonsevere COVID-19 patients yielded favorable outcomes during the COVID-19 pandemic in Thailand.

This study aimed to assess the clinical characteristics of patients who registered at the Siriraj Favipiravir Clinic and to share our experiences in this comparatively unique clinical setting. This retrospective study included patients who registered at the Siriraj Favipiravir Clinic during August 11, 2021 to September 14, 2021. Included adult patients were those with severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019 [COVID-19]) infection confirmed by antigen test kit (ATK) or real-time reverse transcription-polymerase chain reaction, no favipiravir contraindication, no prior COVID-19 treatment, and not receiving care from another medical facility. Demographic data and outcomes were collected and analyzed. Of the 1168 patients (mean age: 44.8 ± 16.4 years, 55.7% female) who registered at the clinic, 117 (10%) did not meet the treatment criteria, and 141 (12%) patients did not pick up their medication. One-third of patients had at least 1 symptom that indicated severe disease. Higher proportion of unvaccinated status (56.7% vs 47.5%, P = .005), higher proportion of persons with risk factors for disease progression (37.7% vs 31.3%, P = .028), and longer duration between the date of clinic registration and the date of positive diagnostic test (3 vs 2 days, P = .004) were significantly more commonly observed in the severe disease group compared to the nonsevere disease group. The duration between symptom onset and the date of clinic registration was significantly longer in the real-time reverse transcription-polymerase chain reaction group than in the ATK group (6 vs 4 days, P < .001). Most patients (90.0%) had completed favipiravir treatment regimen. The improvement and mortality rates were 86.7% and 1.2%, respectively. COVID-19 severity is associated with vaccination status, baseline risk factors, and timing between disease detection and treatment. The use of ATK influences patients to seek treatment significantly earlier in ambulatory setting. Our early diagnosis and antiviral treatment strategy yielded favorable results in an outpatient setting during a COVID-19 outbreak in Thailand.

Background: In December 2021, Omicron replaced Delta as the dominant coronavirus disease 2019 (COVID-19) variant in Thailand. Both variants embody diverse epidemiological trends and immunogenicity. We investigated whether Delta and Omicron patients’ biological and clinical characteristics and immunogenicity differed post-COVID-19 infection. Methods: This retrospective cohort study investigated the clinical outcomes and laboratory data of 5181 patients with mild-to-moderate COVID-19 (Delta, 2704; Omicron, 2477) under home isolation. We evaluated anti-receptor-binding domain immunoglobulin G (anti-RBD IgG) and surrogate viral neutralizing (sVNT) activity in 495 individuals post-COVID-19 infection during the Delta pandemic. Results: Approximately 84% of all patients received favipiravir. The median cycle threshold (Ct) values were lower for Omicron patients than Delta patients (19 vs. 21; p < 0.001), regardless of vaccination status. Upper respiratory tract symptoms were more frequent with Omicron patients than Delta patients. There were no significant associations between Ct and Omicron symptoms (95% confidence interval 0.98–1.02). A two-dose vaccine regimen reduced hospital readmission by 10% to 30% and death by under 1%. Anti-RBD IgG and sVNT against Delta were higher among older individuals post-COVID-19 infection. Older individuals expressed anti-RBD IgG and sVNT for a more extended period after two-dose vaccination than other age groups. Conclusions: After a full vaccination course, breakthrough mild-to-moderate Delta and Omicron infections have limited immunogenicity. Prior infections exert reduced protection against later reinfection or infection from novel variants. However, this protection may be sufficient to prevent hospitalization and death, particularly in countries where vaccine supplies are limited.