An unexpected IgE anti-receptor binding domain response following natural infection and different types of SARS-CoV-2 vaccines.

Humoral response to SARS-CoV-2 has been studied, predominantly the classical IgG and its subclasses. Although IgE antibodies are typically specific to allergens or parasites, a few reports describe their production in response to SARS-CoV-2 and other viruses. Here, we investigated IgE specific to receptor binding domain (RBD) of SARS-CoV-2 in a Brazilian cohort following natural infection and vaccination. Samples from 59 volunteers were assessed after infection (COVID-19), primary immunization with vectored (ChAdOx1) or inactivated (CoronaVac) vaccines, and booster immunization with mRNA (BNT162b2) vaccine. Natural COVID-19 induced IgE, but vaccination increased its levels. Subjects vaccinated with two doses of ChAdOx1 exhibited a more robust response than those immunized with two doses of CoronaVac; however, after boosting with BNT162b2, all groups presented similar IgE levels. IgE showed intermediate-to-high avidity, especially after the booster vaccine. We also found IgG4 antibodies, mainly after the booster, and they moderately correlated with IgE. ELISA results were confirmed by control assays, using IgG depletion by protein G and lack of reactivity with heterologous antigen. In our cohort, no clinical data could be associated with the IgE response. We advocate for further research on IgE and its role in viral immunity, extending beyond allergies and parasitic infections.

Lamivudine-based two-drug regimens with dolutegravir or protease inhibitor: Virological suppression in spite of previous therapy failure or renal dysfunction.

BACKGROUND: Two-Drug Regimens (2DR) have proven effective in clinical trials but real-world data, especially in resource-limited settings, is limited. OBJECTIVES: To evaluate viral suppression of lamivudine-based 2DR, with dolutegravir or ritonavir-boosted protease inhibitor (lopinavir/r, atazanavir/r or darunavir/r), among all cases regardless of selection criteria. PATIENTS AND METHODS: A retrospective study, conducted in an HIV clinic in the metropolitan area of São Paulo, Brazil. Per-protocol failure was defined as viremia above 200 copies/mL at outcome. Intention-To-Treat-Exposed (ITT-E) failure was considered for those who initiated 2DR but subsequently had either (i) Delay over 30 days in Antiretroviral Treatment (ART) dispensation, (ii) ART changed or (iii) Viremia > 200 copies/mL in the last observation using 2DR. RESULTS: Out of 278 patients initiating 2DR, 99.6% had viremia below 200 copies/mL at last observation, 97.8% below 50 copies/mL. Lamivudine resistance, either documented (M184V) or presumed (viremia > 200 copies/mL over a month using 3TC) was present in 11% of cases that showed lower suppression rates (97%), but with no significant hazard ratio to fail per ITT-E (1.24, p = 0.78). Decreased kidney function, present in 18 cases, showed of 4.69 hazard ratio (p = 0.02) per ITT-E for failure (3/18). As per protocol analysis, three failures occurred, none with renal dysfunction. CONCLUSIONS: The 2DR is feasible, with robust suppression rates, even when 3TC resistance or renal dysfunction is present, and close monitoring of these cases may guarantee long-term suppression.

A simple algorithm for selecting cases to investigate acute and early HIV infections in low- and middle-income countries.

We documented the outcome of an over 10-year (2011-2021) effort to diagnose acute and early HIV infections (AEHI) in an Infectious Diseases Outpatient Clinic with limited resources. Of a total of 132, 119 HIV-RNA tests were performed from 2017 to 2020, 12 cases were identified, using a simple algorithm: risk exposure of 6 weeks or less before the visit and/or symptoms compatible with acute retroviral syndrome 7-30 days after exposure and/or undetermined 3rd generation rapid diagnostic test or serology. AEHI diagnoses varied from 2.4% among asymptomatic to 25% for undetermined serology cases using this simple screening applicable to different settings.

Field evaluation of COVID-19 antigen tests versus RNA based detection: Potential lower sensitivity compensated by immediate results, technical simplicity, and low cost.

One year into the coronavirus disease 2019 (COVID-19) pandemic, diagnostic strategies, although central for contact tracing and other preventive measures, are still limited. To meet the global demand, lower cost and faster antigen tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection are a convenient alternative to the gold standard reverse transcription-polymerase chain reaction (RT-PCR) assay. We tested laboratory-based RT-PCR RNA detection and two rapid antigen detection (RAD) tests, based on the immunochromatography test for nucleocapsid protein of SARS-CoV-2 (COVID-19 Ag ECO Test, ECO Diagnóstica, and Panbio COVID-19 Ag Rapid Test Abbott). Paired collection and testing were done in a small prospective open study in three clinical services in São Paulo, constituted of mostly symptomatic volunteers at collection (97%, 109/112) for a median of 4 days (interquartile range: 3-6), ranging from 1 to 30. Among the 108 paired RT-PCR/RAD tests, results were concordant in 96.4% (101/108). The test's performance was comparable, with an overall sensitivity of 87% and a specificity of 96%. These observations add to other data that suggest that antigen tests may provide reasonable sensitivity and specificity and deserve a role to improve testing strategies, especially in resource-limited settings.