Correlation between SARS-COV-2 antibody screening by immunoassay and neutralizing antibody testing.

BACKGROUND: The efficacy of convalescent plasma (CP), an alternative for the treatment of COVID-19, depends on high titers of neutralizing antibodies (nAbs), but assays for quantifying nAbs are not widely available. Our goal was to develop a strategy to predict high titers of nAbs based on the results of anti-SARS-CoV-2 immunoassays and the clinical characteristics of CP donors. STUDY DESIGN AND METHODS: A total of 214 CP donors were enrolled and tested for the presence of anti-SARS-CoV-2 antibodies (IgG) using two commercial immunoassays: EUROIMMUN (ELISA) and Abbott (Chemiluminescence). Quantification of nAbs was performed using the Cytopathic Effect-based Virus Neutralization test. Three criteria for identifying donors with nAbs ≥ 1:160 were tested: - C1: Curve ROC; - C2: Conditional decision tree considering only the IA results and - C3: Conditional decision tree including both the IA results and the clinical variables. RESULTS: The performance of the immunoassays was similar referring to both S/CO and predictive value for identifying nAbs titers ≥1:160. Regarding the studied criteria for identifying CP donors with high nAbs titers: (a) C1 showed 76.1% accuracy if S/CO = 4.65, (b) C2 presented 76.1% accuracy if S/CO ≥4.57 and (c) C3 had 71.6% accuracy if S/CO was ≥4.57 or if S/CO was between 2.68-4.57 and the last COVID-19-related symptoms were recent (within 19 days). CONCLUSION: SARS-CoV-2 IgG immunoassays (S/CO) can be used to predict high anti-SARS-CoV-2 nAbs titers. This study has proposed different criteria for identifying donors with ≥1:160 nAbs titers, all with high efficacy.

COVID-19 convalescent plasma cohort study: Evaluation of the association between both donor and recipient neutralizing antibody titers and patient outcomes.

BACKGROUND: Current evidence regarding COVID-19 convalescent plasma (CCP) transfusion practices is limited and heterogeneous. We aimed to determine the impact of the use of CCP transfusion in patients with previous circulating neutralizing antibodies (nAbs) in COVID-19. METHODS: Prospective cohort including 102 patients with COVID-19 transfused with ABO compatible CCP on days 0-2 after enrollment. Clinical status of patients was assessed using the adapted World Health Organization (WHO) ordinal scale on days 0, 5, and 14. The nAbs titration was performed using the cytopathic effect-based virus neutralization test with SARS-CoV-2 (GenBank MT126808.1). The primary outcome was clinical improvement on day 14, defined as a reduction of at least two points on the adapted WHO ordinal scale. Secondary outcomes were the number of intensive care unit (ICU)-free days and the number of invasive mechanical ventilation-free days. RESULTS: Both nAbs of CCP units transfused (p < 0.001) and nAbs of patients before CCP transfusions (p = 0.028) were associated with clinical improvements by day 14. No significant associations between nAbs of patients or CCP units transfused were observed in the number of ICU or mechanical ventilation-free days. Administration of CCP units after 10 days of symptom onset resulted in a decrease in ICU-free days (p < 0.001) and mechanical ventilation-free days (p < 0.001). CONCLUSION: Transfusion of high titer nAbs CCP units may be a determinant in clinical strategies against COVID-19. We consider these data as useful parameters to guide future CCP transfusion practices.

Anti-A and SARS-CoV-2: an intriguing association.

BACKGROUND: Blood groups and anti-A isohemagglutinin may be involved in susceptibility to SARS-CoV-2 infection. MATERIALS AND METHODS: We retrospectively studied 268 COVID-19 convalescent plasma donors and 162 COVID-19 inpatients (total 430 subjects, confirmed by RT-PCR) and 2,212 healthy volunteer first-time blood donors as a control group. These were further divided into two groups: those with anti-A (blood types O and B) and those without it (types A and AB). Titres of nucleoproteins, and neutralizing SARS-CoV-2 antibody were measured in the convalescent plasma donors and inpatients. Multivariate logistic regression and non-parametric tests were applied. RESULTS: Persons having types O or B showed less infection prevalence than those of types A or AB (OR = 0·62, 95% CI 0·50-0·78; P < 0·001), but there was no difference when COVID-19 inpatients were analysed. Immunoglobulins M, G and A were lower in COVID-19 subjects of types O or B group than those of A or AB (0·16 vs. 0·19; P = 0·03, 2·11 vs. 2·55; P = 0·02, 0·23 vs. 0·32; P = 0·03, respectively). CONCLUSION: In this retrospective cohort, COVID-19 individuals were less likely to belong to blood types O and B, and also had lower SARS-CoV-2 antibody titres than A and AB individuals. COVID-19 severity did not associate with the blood groups.

SARS-CoV-2 isolation from the first reported patients in Brazil and establishment of a coordinated task network.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was confirmed in Brazil in February 2020, the first cases were followed by an increase in the number of cases throughout the country, resulting in an important public health crisis that requires fast and coordinated responses. OBJECTIVES: The objective of this work is to describe the isolation and propagation properties of SARS-CoV-2 isolates from the first confirmed cases of coronavirus disease 2019 (COVID-19) in Brazil. METHODS: After diagnosis in patients that returned from Italy to the São Paulo city in late February by RT-PCR, SARS-CoV-2 isolates were obtained in cell cultures and characterised by full genome sequencing, electron microscopy and in vitro replication properties. FINDINGS: The virus isolate was recovered from nasopharyngeal specimen, propagated in Vero cells (E6, CCL-81 and hSLAM), with clear cytopathic effects, and characterised by full genome sequencing, electron microscopy and in vitro replication properties. Virus stocks - viable (titre 2.11 × 106 TCID50/mL, titre 1.5 × 106 PFUs/mL) and inactivated from isolate SARS.CoV2/SP02.2020.HIAE.Br were prepared and set available to the public health authorities and the scientific community in Brazil and abroad. MAIN CONCLUSION: We believe that the protocols for virus growth and studies here described and the distribution initiative may constitute a viable model for other developing countries, not only to help a rapid effective pandemic response, but also to facilitate and support basic scientific research.

Zika virus infection impairs synaptogenesis, induces neuroinflammation, and could be an environmental risk factor for autism spectrum disorder outcome.

Zika virus (ZIKV) infection was first associated with Central Nervous System (CNS) infections in Brazil in 2015, correlated with an increased number of newborns with microcephaly, which ended up characterizing the Congenital Zika Syndrome (CZS). Here, we investigated the impact of ZIKV infection on the functionality of iPSC-derived astrocytes. Besides, we extrapolated our findings to a Brazilian cohort of 136 CZS children and validated our results using a mouse model. Interestingly, ZIKV infection in neuroprogenitor cells compromises cell migration and causes apoptosis but does not interfere in astrocyte generation. Moreover, infected astrocytes lost their ability to uptake glutamate while expressing more glutamate transporters and secreted higher levels of IL-6. Besides, infected astrocytes secreted factors that impaired neuronal synaptogenesis. Since these biological endophenotypes were already related to Autism Spectrum Disorder (ASD), we extrapolated these results to a cohort of children, now 6-7 years old, and found seven children with ASD diagnosis (5.14 %). Additionally, mice infected by ZIKV revealed autistic-like behaviors, with a significant increase of IL-6 mRNA levels in the brain. Considering these evidence, we inferred that ZIKV infection during pregnancy might lead to synaptogenesis impairment and neuroinflammation, which could increase the risk for ASD.

Rabies in southeast Brazil: a change in the epidemiological pattern.

This epidemiological study was conducted using antigenic and genetic characterisation of rabies virus isolates obtained from different animal species in the southeast of Brazil from 1993 to 2007. An alteration in the epidemiological profile was observed. One hundred two samples were tested using a panel of eight monoclonal antibodies, and 94 were genetically characterised by sequencing the nucleoprotein gene. From 1993 to 1997, antigenic variant 2 (AgV-2), related to a rabies virus maintained in dog populations, was responsible for rabies cases in dogs, cats, cattle and horses. Antigenic variant 3 (AgV-3), associated with Desmodus rotundus, was detected in a few cattle samples from rural areas. From 1998 to 2007, rabies virus was detected in bats and urban pets, and four distinct variants were identified. A nucleotide similarity analysis resulted in two primary groups comprising the dog and bat antigenic variants and showing the distinct endemic cycles maintained in the different animal species in this region.

Isolated specific IgA against respiratory viruses, Influenza or SARS-CoV-2, present in the saliva of a fraction of healthy and asymptomatic volunteers.

OBJECTIVES: Defense against respiratory viruses depends on an immune response present in the mucosa, as saliva IgA secretes antibodies. During the pandemic, such as influenza or SARS-CoV-2, most infected patients are asymptomatic but retain specific antibodies post-infection. The authors evaluated IgG and IgA antibodies against SARS-CoV-2 and influenza in the saliva of asymptomatic volunteers, validated with controls or vaccinated individuals. METHODS: The authors detected specific antibodies by validated conventional ELISA using natural SARS-CoV-2 antigens from infected Vero cells or capture-ELISA for influenza using natural antigens of the influenza vaccine. RESULTS: Saliva from influenza-vaccinated individuals had more IgA than paired serum, contrary to the findings for specific IgG. In COVID-19-vaccinated samples, specific IgA in saliva increased after vaccination, but IgG levels were high after the first dose. In saliva from the asymptomatic population (226), anti-Influenza IgG was found in 57.5% (130) of samples, higher than IgA, found in 35% (79) of samples. IgA results were similar for SARS-CoV-2, with IgA present in 30% (68) of samples, while IgG was less present, in 44.2% (100) of samples. The proportion of influenza IgG responders was higher than that for SARS-CoV-2 IgG, but both populations presented similar proportions of IgA responders, possibly due to variable memory B cell survival. For both viruses, the authors found an important proportion (> 10%) of IgA+IgG- samples, suggesting the occurrence of humoral immunity directed to the mucosa. CONCLUSION: Specific antibodies for respiratory viruses in saliva are found in either infection or vaccination and are a convenient and sensitive diagnostic tool for host immune response.

Knowledge, Attitudes and Practices Regarding Sylvatic Rabies among High-Risk Households in Ceará State, Brazil.

Rabies transmitted by sylvatic populations has become an increasing concern in Brazil. A total of 113 participants with a history of contact with sylvatic populations were interviewed in 27 municipalities of Ceará State in northeast Brazil. Questionnaires included questions on knowledge, attitudes and practices (KAP) regarding sylvatic rabies. Most of the respondents (92%) knew about rabies and confirmed at least one species that transmitted the disease (79.6%). Of these respondents, 69% mentioned monkeys, and 67.2% mentioned dogs. However, 16% of the respondents listed an incorrect species. In general, knowledge on the symptoms and signs and on prevention measures was weak. The majority raised pets (93.8%), most commonly dogs and cats, and, of all the pets, 85.7% were claimed to be vaccinated against rabies. A total of 67.3% reported the appearance of free-living wild animals around their houses, mostly marmosets and wild canids; 18.3% reported that sylvatic populations had attacked animals or humans. Seventy-three percent had raised or still were raising wild animals as pets, mostly capuchin monkeys (79.5%) and marmosets (24.1%). This is the first KAP study on sylvatic rabies in Brazil. The data indicate important knowledge gaps and risk behavior within a high-risk population. There is a need for strengthening and improving sylvatic rabies surveillance and control, combined with the intensification of education and information campaigns.

Lack of Evidence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Spillover in Free-Living Neotropical Non-Human Primates, Brazil.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the agent of coronavirus disease 2019 (COVID-19), is responsible for the worst pandemic of the 21st century. Like all human coronaviruses, SARS-CoV-2 originated in a wildlife reservoir, most likely from bats. As SARS-CoV-2 has spread across the globe in humans, it has spilled over to infect a variety of non-human animal species in domestic, farm, and zoo settings. Additionally, a broad range of species, including one neotropical monkey, have proven to be susceptible to experimental infection with SARS-CoV-2. Together, these findings raise the specter of establishment of novel enzootic cycles of SARS-CoV-2. To assess the potential exposure of free-living non-human primates to SARS-CoV-2, we sampled 60 neotropical monkeys living in proximity to Manaus and São José do Rio Preto, two hotspots for COVID-19 in Brazil. Our molecular and serological tests detected no evidence of SAR-CoV-2 infection among these populations. While this result is reassuring, sustained surveillance efforts of wildlife living in close association with human populations is warranted, given the stochastic nature of spillover events and the enormous implications of SARS-CoV-2 spillover for human health.

Social determinants associated with Zika virus infection in pregnant women.

This study aims to describe the sociodemographic determinants associated with exposure to Zika Virus (ZIKV) in pregnant women during the 2015-2016 epidemic in Salvador, Brazil. METHODS: We recruited women who gave birth between October 2015 and January 2016 to a cross-sectional study at a referral maternity hospital in Salvador, Brazil. We collected information on their demographic, socioeconomic, and clinical characteristics, and evaluated their ZIKV exposure using a plaque reduction neutralization test. Logistic regression was then used to assess the relationship between these social determinants and ZIKV exposure status. RESULTS: We included 469 pregnant women, of whom 61% had a positive ZIKV result. Multivariate analysis found that lower education (adjusted Prevalence Rate [aPR] 1.21; 95%CI 1.04-1.35) and food insecurity (aPR 1.17; 95%CI 1.01-1.30) were positively associated with ZIKV exposure. Additionally, age was negatively associated with the infection risk (aPR 0.99; 95%CI 0.97-0.998). CONCLUSION: Eve after controlling for age, differences in key social determinants, as education and food security, were associated with the risk of ZIKV infection among pregnant women in Brazil. Our findings elucidate risk factors that can be targeted by future interventions to reduce the impact of ZIKV infection in this vulnerable population.

Beneficial effects of a mouthwash containing an antiviral phthalocyanine derivative on the length of hospital stay for COVID-19: randomised trial.

The risk of contamination and dissemination by SARS-CoV-2 has a strong link with nasal, oral and pharyngeal cavities. Recently, our research group observed the promising performance of an anionic phthalocyanine derivative (APD) used in a mouthwash protocol without photoexcitation; this protocol improved the general clinical condition of patients infected with SARS-CoV-2. The present two-arm study evaluated in vitro the antiviral activity and cytotoxicity of APD. Additionally, a triple-blind randomized controlled trial was conducted with 41 hospitalized patients who tested positive for COVID-19. All the included patients received World Health Organization standard care hospital treatment (non-intensive care) plus active mouthwash (experimental group AM/n = 20) or nonactive mouthwash (control group NAM/n = 21). The adjunct mouthwash intervention protocol used in both groups consisted one-minute gargling/rinsing / 5 times/day until hospital discharge. Groups were compared considering age, number of comorbidities, duration of symptoms prior admission and length of hospital stay (LOS). The associations between group and sex, age range, presence of comorbidities, admission to Intensive care unit (ICU) and death were also evaluated. The in vitro evaluation demonstrated that APD compound was highly effective for reduction of SARS-CoV-2 viral load in the 1.0 mg/mL (99.96%) to 0.125 mg/mL (92.65%) range without causing cytotoxicity. Regarding the clinical trial, the median LOS of the AM group was significantly shortened (4 days) compared with that of the NAM group (7 days) (p = 0.0314). Additionally, gargling/rinsing with APD was very helpful in reducing the severity of symptoms (no ICU care was needed) compared to not gargling/rinsing with APD (28.6% of the patients in the NAM group needed ICU care, and 50% of this ICU subgroup passed way, p = 0.0207). This study indicated that the mechanical action of the protocol involving mouthwash containing a compound with antiviral effects against SARS-CoV-2 may reduce the symptoms of the patients and the spread of infection. The use of APD in a mouthwash as an adjuvant the hospital COVID-19 treatment presented no contraindication and reduced the hospital stay period.Trial registration: The clinical study was registered at REBEC-Brazilian Clinical Trial Register (RBR-58ftdj).

Heterogeneous development of children with Congenital Zika Syndrome-associated microcephaly.

OBJECTIVE: To describe the neurological and neurodevelopmental outcomes of children with Congenital Zika Syndrome (CZS) associated microcephaly beyond 2 years of age. METHOD: We followed children with CZS-associated microcephaly in an outpatient clinic in Salvador, Brazil. Neurological and neurodevelopmental assessments were performed using the Hammersmith Infant Neurological Examination (HINE) and Bayley Scales of Infant and Toddler Neurodevelopment (Bayley-III) respectively. RESULTS: Of the 42 children included, 19 were male (45.2%); median (interquartile range) age at neurological evaluation was 28 (25-32) months, and 36 (85.7%) had severe microcephaly. HINE and Bayley-III results were completed for 35/42 (83.3%) and 33/42 (78.5%) children respectively. Bayley-III identified a severe developmental delay in 32/33 (97.0%) children while 1/33 (3.0%) had only a mild delay. In the multivariable analysis, we found that Bayley-III and HINE scores were correlated. Better HINE scores were associated with higher Bayley-III cognitive raw scores (ß = 0.29; CI 95% = 0.02-0.57) and motor raw scores (ß = 0.43; CI 95% = 0.04-0.82) after adjusting for head circumference, prematurity, and age at neurodevelopmental evaluation. Furthermore, we found that greater head circumference at follow up was associated with higher cognitive (ß = 1.27; CI 95% = 0.01-2.53) and motor raw scores (ß = 2.03; CI 95% = 0.25-3.81). CONCLUSION: Children with CZS-associated microcephaly demonstrate severe neurodevelopmental delays and slower growth rates than their peers over time. Still, they have remarkably heterogeneous neurodevelopmental profiles according to neurological exam scores which correlate with their long-term outcomes. We found that HINE scores effectively captured the heterogeneity of neurological capabilities among these children and could be predictive of cognitive and motor development progress.

Increased detection of rabies virus in bats in Ceará State (Northeast Brazil) after implementation of a passive surveillance programme.

The intensification of dog, cat and livestock vaccination campaigns significantly reduced rabies cases in humans and domestic animals in Ceará State, Brazil. However, sylvatic animals-bats (order Chiroptera), wild canids, raccoons and non-human primates- remain as reservoirs for the virus. Our hypothesis is that surveillance and monitoring of rabies virus in bats, especially passive surveillance, is of fundamental importance, besides the implementation of health education and strengthening of surveillance actions in humans exposed to aggressions. Thus, we assessed the occurrence of rabies virus in animals focusing on bats, before and after launching of the Sylvatic Rabies Surveillance Program in 2010. Surveillance data from the 184 municipalities of Ceará State were analysed, collected during the periods 2003-2010 (active surveillance) and 2011-2016 (passive surveillance), respectively. A total of 13,543 mammalian samples were received for rabies diagnosis from 2003 to 2016. Of these, 10,960 were from dogs or cats (80.9%), 1,180 from bats (8.7%), 806 from other sylvatic animals (foxes, marmosets, raccoons; 6.0%) and 597 from herbivores (cattle, goats, sheep, equines, pigs; 4.4%). A total of 588 (4.3%) samples were positive for rabies. About 8.4% (99/1,180) of the bat samples were infected with rabies virus, 92 (92.9%) of these were from non-haematophagous bat species and 7 (7.1%) from haematophagous species. The number of bat samples received and infection rates increased considerably, after a shift from active surveillance (9/355 [2.5%] samples positive), to passive surveillance (90/825 [10.9%] samples positive). Surveillance of rabies virus in bats is fundamental for human and domestic animal health in Ceará State. Bats have to be considered as targets in surveillance and control programmes. Virus lineages should be characterized to increase knowledge on transmission dynamics of sylvatic rabies virus to domestic animals and the human population, and to provide additional evidence for planning and implementation of improved control measures.

Zika virus seroprevalence in blood donors from the Northeastern region of São Paulo State, Brazil, between 2015 and 2017.

OBJECTIVES: Although primarily transmitted by Aedes aegypti mosquitos, Zika virus (ZIKV) can also be transmitted by blood transfusion, due to the fact that some of the infected donors can establish asymptomatic viremia. ZIKV seroprevalence in Brazilian blood donors is unknown. The main reason for this gap in the knowledge originates from the difficulty in evaluating ZIKV humoral immunity due to antigenic cross-reactivity between the different Brazilian flaviviruses and, in particular, dengue virus (DENV). The objective of this study was to evaluate the anti-ZIKV IgG prevalence in blood donors from the Northeast region of the São Paulo State, Brazil, which experienced a ZIKV outbreak in 2016. METHODS: We evaluated the ZIKV seroprevalence using the NS1 anti-ZIKV IgG test (Euroimmun), followed by confirmation of the positive and borderline results using the Plaque Reduction Neutralization Test (PRNT). ZIKV seroprevalence was estimated by testing plasma samples collected in 2015 (before the ZIKV outbreak), 2016 (during the outbreak) and 2017 (after the outbreak). In order to investigate possible antigenic cross - reactivity between ZIKV and DENV we also included samples that were taken well before the ZIKV outbreak, in years 2010 and 2013. RESULTS: The results obtained by the Euroimmun anti-ZIKV IgG test demonstrated ZIKV seroreactivity in 2015, 2016, and 2017 with prevalences of 5.3%, 12.8% and 13.2%, respectively. The inclusion of blood donor samples from 2010 to 2013, demonstrated anti-ZIKV IgG reactivity only for 2013 (1.7%). The PRNT testing of the ZIKV positive and borderline ELISA reacting samples generated positive results only for the years of 2016 and 2017 (prevalences of 5.6% and 9.1%) which coincided with the introduction of ZIKV in our region. CONCLUSIONS: Our results estimate for the first time the ZIKV seroprevalence among Brazilian blood donors from a region with apparently extensive ZIKV circulation and which, at the same time, is highly endemic for DENV. We detected relatively low ZIKV seroprevalence in blood donors from the studied region probably due to the lower intensity of the outbreak compared to other Brazilian locations. Our study adds to the global understanding of ZIKV circulation and the herd immunity of the exposed population.

Phylogenetic analysis of near full-length sequences of the Desmodus rotundus genetic lineage of rabies virus.

The World Health Organization (WHO), reports that rabies causes tens of thousands of deaths every year killing humans, non-human primates and other animals. Rabies continues to be a public health issue, despite the existence of effective vaccines. The dogs remain the primary reservoir and transmitter of rabies to humans globally. In the Americas, bats are regarded as the second most common source of rabies virus to humans. The vampire bat Desmodus rotundus has been identified as a natural reservoir of rabies virus (RABV) in this region. The complete genome of the RABV variant maintained by populations of vampire bats D. rotundus has rarely been reported. In this study, we sequenced and analyzed the genome of a RABV variant detected in D. rotundus. The sample, collected from an endemic area in São Paulo State, was phylogenetically compared with the genome of the standard sample for species Rabies virus as well as other samples belonging to terrestrial and bat-associated cycles of rabies transmission, available in GenBank. Distinct patterns linked to the genetic lineage were identified. These data can aid in the understanding of the molecular epidemiology of this virus and the epidemiological importance of this species in the transmission of the RABV.

Natural versus Recombinant Viral Antigens in SARS-CoV-2 Serology: Challenges in Optimizing Laboratory Diagnosis of COVID-19.

OBJECTIVES: COVID-19 is a public health emergency of international concern whose detection in recovered asymptomatic patients is dependent on accurate diagnosis as it enables the estimation of the susceptibility of the population to the infection. This demand has resulted in the development of several commercial assays employing recombinant proteins, but the results of these assays are not reliable as they do not involve comparison with natural viral antigens. We independently used the SARS-CoV-2 whole viral antigen (WVA) and recombinant nucleocapsid protein (rNP) to develop in-house ELISAs for IgG detection; the results of these ELISAs were then compared to obtain reliable results. METHODS: WVA and rNP ELISAs were performed on COVID-19 negative sera from patients before the pandemic in Brazil, and on RT-qPCR-positive or SARS-CoV-2-IgG against rNP and IgG against WVA-positive samples from recently infected patients in Sao Paulo, Brazil. RESULTS: Both ELISAs detected a large fraction of infected patients but exhibited certain drawbacks. Higher signals and lower numbers of false-negatives were observed in rNP ELISA; however, a higher fraction of false-positives was observed in control groups. A high number of false-negatives was observed with WVA ELISA. Correlating the results of rNP and WVA ELISAs resulted in improved performance for COVID-19 diagnosis. CONCLUSION: The choice of antigen is an important aspect in optimizing the laboratory diagnosis of COVID-19. The use of rNP ELISA for the detection of anti-SARS-CoV-2 IgG antibodies seems promising, but comparison of the results with those of WVA ELISA is crucial for accurate test development prior to commercialization. IgG serology using several assays, and with the spectral patterns of SARS-CoV-2, resulted in confusing information that must be clarified before the establishment of diagnostic serology criteria.

Multisystem Inflammatory Syndrome Associated With COVID-19 With Neurologic Manifestations in a Child: A Brief Report.

Although first considered a benign infection, recent studies have disclosed severe and potentially lethal inflammatory manifestations of COVID-19 in children. We report the case of a 4-year-old child with a post-infectious multisystem inflammatory syndrome associated with COVID-19, with a Kawasaki-like shock and prominent neurologic features, for whom a cytokine storm and reduced brain-derived neurotrophic factor were well documented.

Lower cost alternatives for molecular diagnosis of COVID-19: conventional RT-PCR and SYBR Green-based RT-qPCR.

In March 2020, WHO declared a pandemic state due to SARS-CoV-2 having spread. TaqMan-based real-time RT-qPCR is currently the gold standard for COVID-19 diagnosis. However, it is a high-cost assay, inaccessible for the majority of laboratories around the world, making it difficult to diagnose on a large scale. The objective of this study was to standardize lower cost molecular methods for SARS-CoV-2 identification. E gene primers previously determined for TaqMan assays by Colman et al. (2020) were adapted in SYBR Green assay and RT-PCR conventional. The cross-reactivity test was performed with 17 positive samples for other respiratory viruses, and the sensibility test was performed with 8 dilutions (10 based) of SARS-CoV-2 isolated and 63 SARS-CoV-2-positive samples. The SYBR Green assays and conventional RT-PCR have not shown amplification of the 17 respiratory samples positives for other viruses. The SYBR Green-based assay was able to detect all 8 dilutions of the isolate. The conventional PCR detected until 107 dilution, both assays detected the majority of the 63 samples, 98.42% of positivity in SYBR Green, and 93% in conventional PCR. The average Ct variation between SYBR Green and TaqMan was 1.92 and the highest Ct detected by conventional PCR was 35.98. Both of the proposed assays are less sensitive than the current gold standard; however, our data shows a low sensibility variation, suggesting that these methods could be used by laboratories as a lower cost molecular method for SARS-CoV-2 diagnosis.

Isolated specific IgA against respiratory viruses, Influenza or SARS-CoV-2, present in the saliva of a fraction of healthy and asymptomatic volunteers

Abstract Objectives: Defense against respiratory viruses depends on an immune response present in the mucosa, as saliva IgA secretes antibodies. During the pandemic, such as influenza or SARS-CoV-2, most infected patients are asymptomatic but retain specific antibodies post-infection. The authors evaluated IgG and IgA antibodies against SARS-CoV-2 and influenza in the saliva of asymptomatic volunteers, validated with controls or vaccinated individuals. Methods: The authors detected specific antibodies by validated conventional ELISA using natural SARS-CoV-2 antigens from infected Vero cells or capture-ELISA for influenza using natural antigens of the influenza vaccine. Results: Saliva from influenza-vaccinated individuals had more IgA than paired serum, contrary to the findings for specific IgG. In COVID-19-vaccinated samples, specific IgA in saliva increased after vaccination, but IgG levels were high after the first dose. In saliva from the asymptomatic population (226), anti-Influenza IgG was found in 57.5% (130) of samples, higher than IgA, found in 35% (79) of samples. IgA results were similar for SARS-CoV-2, with IgA present in 30% (68) of samples, while IgG was less present, in 44.2% (100) of samples. The proportion of influenza IgG responders was higher than that for SARS-CoV-2 IgG, but both populations presented similar proportions of IgA responders, possibly due to variable memory B cell survival. For both viruses, the authors found an important proportion (> 10%) of IgA+IgG- samples, suggesting the occurrence of humoral immunity directed to the mucosa. Conclusion: Specific antibodies for respiratory viruses in saliva are found in either infection or vaccination and are a convenient and sensitive diagnostic tool for host immune response.