Humoral correlates of protection against influenza A H3N2 virus infection.

BACKGROUND: Influenza virus remains a threat to human health, but gaps remain in our knowledge of the humoral correlates of protection against influenza virus A/H3N2, limiting our ability to generate effective, broadly protective vaccines. The role of antibodies against the hemagglutinin (HA) stalk, a highly conserved but immunologically sub-dominant region, has not been established for influenza virus A/H3N2. METHODS: Household transmission studies were conducted in Managua, Nicaragua across three influenza seasons. Household contacts were tested for influenza virus infection using RT-PCR. We compared pre-existing antibody levels against full-length hemagglutinin (FLHA), HA stalk, and neuraminidase (NA) measured by enzyme-linked immunosorbent assay (ELISA), along with HA inhibition assay (HAI) titers, between infected and uninfected participants. RESULTS: A total of 899 individuals participated in household activation, with 329 infections occurring. A four-fold increase in initial HA stalk titers was independently associated with an 18% decrease in the risk of infection (OR=0.82, 95%CI 0.68-0.98, p=0.04). In adults, anti-HA stalk antibodies were independently associated with protection (OR=0.72, 95%CI 0.54-0.95, p=0.02). However, in 0-14-year-olds, anti-NA antibodies (OR=0.67, 95%CI 0.53-0.85, p<0.01) were associated with protection against infection, but anti-HA stalk antibodies were not. CONCLUSIONS: The HA stalk is an independent correlate of protection against A/H3N2 infection, though this association is age dependent. Our results support the continued exploration of the HA stalk as a target for broadly protective influenza vaccines but suggest that the relative benefits may depend on age and influenza virus exposure history.

Macrocheilia as an Atypical Clinical Presentation of Capillary Malformation-Arteriovenous Malformation Type 2.

This case report describes a 53-year-old man with multiple erythematous macules and papules diffusely distributed on the frontal area, cheeks, eyelids, nose, and supralabial skin.

Non-covalent interactions in the diastereoselective synthesis of cis-2,3-dihydrobenzofurans: experimental and computational studies.

The diastereoselective synthesis of 2,3-DHBs has been previously reported via an intramolecular Michael addition reaction using alkali bases such as Cs2CO3 and K2CO3. However, no systematic study has been performed to understand the possible role of bases in the mechanism of the reaction and factors behind the stereoselective outcome of the reaction. Herein, from experimental and theoretical points of view, we disclose the role of the cesium salt in the rate-determining step along the catalytic cycle and the key role of stabilizing non-covalent interactions in the stereoselective outcome of the reaction.

Tissue perfusion pressure enables continuous hemodynamic evaluation and risk prediction in the intensive care unit.

Treatment of circulatory shock in critically ill patients requires management of blood pressure using invasive monitoring, but uncertainty remains as to optimal individual blood pressure targets. Critical closing pressure, which refers to the arterial pressure when blood flow stops, can provide a fundamental measure of vascular tone in response to disease and therapy, but it has not previously been possible to measure this parameter routinely in clinical care. Here we describe a method to continuously measure critical closing pressure in the systemic circulation using readily available blood pressure monitors and then show that tissue perfusion pressure (TPP), defined as the difference between mean arterial pressure and critical closing pressure, provides unique information compared to other hemodynamic parameters. Using analyses of 5,988 admissions to a modern cardiac intensive care unit, and externally validated with 864 admissions to another institution, we show that TPP can predict the risk of mortality, length of hospital stay and peak blood lactate levels. These results indicate that TPP may provide an additional target for blood pressure optimization in patients with circulatory shock.

Increased influenza severity in children in the wake of SARS-CoV-2.

The SARS-CoV-2 pandemic and subsequent interruption of influenza circulation has lowered population immunity to influenza, especially among children with few prepandemic exposures. Using data from a prospective pediatric cohort study based in Managua, Nicaragua, we compared the incidence and severity of influenza A/H3N2 and influenza B/Victoria between 2022 and two prepandemic seasons. We found a higher incidence of A/H3N2 in older children in 2022 compared with pre-2020 and a higher proportion of severe influenza in 2022, primarily among children aged 0-4, suggesting an influence of the SARS-CoV-2 pandemic on influenza incidence and severity in children.

[Soy beverages and women's health: evidence review and experts opinion]. / Bebidas de soja y salud femenina. Revisión de la evidencia y opinión de expertos.

Introduction: Soy drinks are an increasingly consumed option within the Western diet. However, there are concerns about potential endocrine disruptor effects and possible impact on women's reproductive health. This review evaluates scientific documents in gynecology and obstetrics under an evidence-based medicine approach. All methods adhered to PRISMA 2020 declaration guidelines. The evaluated studies do not support a positive association between soy intake and early puberty or breast cancer; instead, a protective effect against such neoplasm was observed. Transplacental passage of soy isoflavones and their presence in breast milk has been reported without any maternal-fetal complications nor congenital malformations. Exposure to soy-derived products appears to have a neutral effect on body weight and bone health. Studies performed in adults indicate that soy may promote a minimal increase in thyrotropin (TSH) in subjects with subclinical hypothyroidism. The impact of soy-based foods on gut microbiota appears favorable, especially when consuming fermented products. Many of the human studies have been conducted with isoflavones supplements, isolated or textured soy proteins. Therefore, the results and conclusions should be interpreted cautiously, as these are not entirely applicable to commercial soy beverages.

Introducción: Las bebidas vegetales de soja constituyen una alternativa dentro de la dieta habitual. Sin embargo, existe la preocupación de potenciales efectos en la salud reproductiva de la mujer por mecanismos de disrupción endócrina. En esta revisión se evalúan documentos científicos en el área de la Ginecología y la Obstetricia bajo el tamiz de la medicina basada en la evidencia, respondiendo preguntas estructuradas. La metodología se apegó a las guías establecidas por la declaración PRISMA 2020. Los estudios evaluados descartan un riesgo incrementado de pubertad precoz o cáncer de mama; incluso se aprecia un efecto protector frente a dicha neoplasia. Se ha reportado el paso transplacentario de isoflavonas de soja y su presencia en la leche materna, sin que ello implique una relación con complicaciones materno-fetales o malformaciones congénitas. La exposición a productos de soja no parece influir sobre el peso corporal y la salud ósea de la mujer. Los estudios en adultos indican que la soja favorece un mínimo incremento de tirotropina (TSH) en personas con antecedente de hipotiroidismo subclínico. El impacto de los alimentos basados en soja sobre la microbiota intestinal parece ser favorable para su diversidad, particularmente al consumir productos fermentados. Muchos de los estudios en humanos han sido realizados con suplementos de isoflavonas o con productos que contienen proteínas aisladas o texturizadas de soja. Por tanto, los resultados y las conclusiones deben interpretarse con cautela ya que no son totalmente extrapolables a las bebidas comerciales de soja.

A comparison of point-tracking algorithms in ultrasound videos from the upper limb.

Tracking points in ultrasound (US) videos can be especially useful to characterize tissues in motion. Tracking algorithms that analyze successive video frames, such as variations of Optical Flow and Lucas-Kanade (LK), exploit frame-to-frame temporal information to track regions of interest. In contrast, convolutional neural-network (CNN) models process each video frame independently of neighboring frames. In this paper, we show that frame-to-frame trackers accumulate error over time. We propose three interpolation-like methods to combat error accumulation and show that all three methods reduce tracking errors in frame-to-frame trackers. On the neural-network end, we show that a CNN-based tracker, DeepLabCut (DLC), outperforms all four frame-to-frame trackers when tracking tissues in motion. DLC is more accurate than the frame-to-frame trackers and less sensitive to variations in types of tissue movement. The only caveat found with DLC comes from its non-temporal tracking strategy, leading to jitter between consecutive frames. Overall, when tracking points in videos of moving tissue, we recommend using DLC when prioritizing accuracy and robustness across movements in videos, and using LK with the proposed error-correction methods for small movements when tracking jitter is unacceptable.

Increased Influenza Severity in Children in the Wake of SARS-CoV-2.

The SARS-CoV-2 pandemic and subsequent interruption of influenza circulation has lowered population immunity to influenza, especially among children with few pre-pandemic exposures. We compared the incidence and severity of influenza A/H3N2 and influenza B/Victoria between 2022 and two pre-pandemic seasons and found an increased frequency of severe influenza in 2022.

Infection-Induced Immunity Is Associated With Protection Against Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Decreased Infectivity.

BACKGROUND: The impact of infection-induced immunity on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has not been well established. Here we estimate the effects of prior infection induced immunity in adults and children on SARS-CoV-2 transmission in households. METHODS: We conducted a household cohort study from March 2020-November 2022 in Managua, Nicaragua; following a housheold SARS-CoV-2 infection, household members are closely monitored for infection. We estimate the association of time period, age, symptoms, and prior infection with secondary attack risk. RESULTS: Overall, transmission occurred in 70.2% of households, 40.9% of household contacts were infected, and the secondary attack risk ranged from 8.1% to 13.9% depending on the time period. Symptomatic infected individuals were more infectious (rate ratio [RR] 21.2, 95% confidence interval [CI]: 7.4-60.7) and participants with a prior infection were half as likely to be infected compared to naïve individuals (RR 0.52, 95% CI:.38-.70). In models stratified by age, prior infection was associated with decreased infectivity in adults and adolescents (secondary attack risk [SAR] 12.3, 95% CI: 10.3, 14.8 vs 17.5, 95% CI: 14.8, 20.7). However, although young children were less likely to transmit, neither prior infection nor symptom presentation was associated with infectivity. During the Omicron era, infection-induced immunity remained protective against infection. CONCLUSIONS: Infection-induced immunity is associated with decreased infectivity for adults and adolescents. Although young children are less infectious, prior infection and asymptomatic presentation did not reduce their infectivity as was seen in adults. As SARS-CoV-2 transitions to endemicity, children may become more important in transmission dynamics.

Epidermotropic B-Cell Lymphoma: A Case of Secondary Cutaneous Splenic Marginal Zone B-Cell Lymphoma With Autoinvolutive and Recurrent Cutaneous Lesions.

ABSTRACT: An 84-year-old woman presented with a 3-month history of a papular rash on the trunk, abdomen, and back. Histopathological examination revealed atypical lymphoid deep and band-like dermal infiltrates with marked epidermotropism. Neoplastic cells expressed B-cell markers (CD20), and clonal immunoglobulin gene rearrangement was observed. A complete peripheral blood study revealed aberrant circulating villous lymphocytes with the expression of B-cell markers (CD20, CD22, and CD79a) and aberrant expression of CD5. A staging workup revealed discrete splenic enlargement and bone marrow and gastrointestinal tract involvement. Skin lesions regressed spontaneously several weeks after diagnosis. Throughout evolution, the patient developed scattered cutaneous nodules and generalized papulo-nodules showing either epidermotropic or nonepidermotropic atypical dermal lymphoid infiltrates. This case illustrates the observation of autoinvolutive and recurrent epidermotropic B-cell atypical cutaneous infiltrates as a characteristic feature of secondary cutaneous involvement in splenic marginal B-cell lymphoma. Previously reported cases of epidermotropic B-cell lymphoma have been reviewed. Concurrent and simultaneous observation of epidermotropic and nonepidermotropic lesions seems to indicate that epidermotropism is an important but nonconstant diagnostic feature of splenic marginal B-cell lymphoma.

SARS-CoV-2 infection-induced immunity and the duration of viral shedding: Results from a Nicaraguan household cohort study.

BACKGROUND: Much of the world's population has been infected with SARS-CoV-2. Thus, immunity from prior infection will play a critical role in future SARS-CoV-2 transmission. We investigated the impact of infection-induced immunity on viral shedding duration and viral load. METHODS: We conducted a household cohort study in Managua, Nicaragua, with an embedded transmission study that closely monitors participants regardless of symptoms. Real-time reverse-transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assays (ELISAs) were used to measure infections and seropositivity, respectively. Blood samples were collected twice annually and surrounding household intensive monitoring periods. We used accelerated failure time models to compare shedding times. Participants vaccinated ≥14 days prior to infection were excluded from primary analyses. RESULTS: There were 600 RT-PCR-confirmed SARS-CoV-2 infections in unvaccinated participants between May 1, 2020, and March 10, 2022, with prior ELISA data. Prior infection was associated with 48% shorter shedding times (event time ratio [ETR] 0.52, 95% CI: 0.39-0.69, mean shedding: 13.7 vs. 26.4 days). A fourfold higher anti-SARS-CoV-2 spike titer was associated with 17% shorter shedding (ETR 0.83, 95% CI: 0.78-0.90). Similarly, maximum viral loads (lowest cycle threshold [CT]) were lower for previously infected individuals (mean CT 29.8 vs. 28.0, p = 4.02 × 10-3 ), for adults and children ≥10 years, but not for children 0-9 years; there was little difference in CT levels for previously infected versus naïve adults aged above 60 years. CONCLUSIONS: Prior infection-induced immunity was associated with shorter viral shedding and lower viral loads, which may be important in the transition from pandemic to endemicity.

Burden and seasonality of primary and secondary symptomatic common cold coronavirus infections in Nicaraguan children.

BACKGROUND: The current SARS-CoV-2 pandemic highlights the need for an increased understanding of coronavirus epidemiology. In a pediatric cohort in Nicaragua, we evaluate the seasonality and burden of common cold coronavirus (ccCoV) infection and evaluate likelihood of symptoms in reinfections. METHODS: Children presenting with symptoms of respiratory illness were tested for each of the four ccCoVs (NL63, 229E, OC43, and HKU1). Annual blood samples collected before ccCoV infection were tested for antibodies against each ccCoV. Seasonality was evaluated using wavelet and generalized additive model (GAM) analyses, and age-period effects were investigated using a Poisson model. We also evaluate the risk of symptom presentation between primary and secondary infections. RESULTS: In our cohort of 2576 children from 2011 to 2016, we observed 595 ccCoV infections and 107 cases of ccCoV-associated lower respiratory infection (LRI). The overall incidence rate was 61.1 per 1000 person years (95% confidence interval (CI): 56.3, 66.2). Children under two had the highest incidence of ccCoV infections and associated LRI. ccCoV incidence rapidly decreases until about age 6. Each ccCoV circulated throughout the year and demonstrated annual periodicity. Peaks of NL63 typically occurred 3 months before 229E peaks and 6 months after OC43 peaks. Approximately 69% of symptomatic ccCoV infections were secondary infections. There was slightly lower risk (rate ratio (RR): 0.90, 95% CI: 0.83, 0.97) of LRI between secondary and primary ccCoV infections among participants under the age of 5. CONCLUSIONS: ccCoV spreads annually among children with the greatest burden among ages 0-1. Reinfection is common; prior infection is associated with slight protection against LRI among the youngest children.

The Nicaraguan Pediatric Influenza Cohort Study, 2011-2019: Influenza Incidence, Seasonality, and Transmission.

BACKGROUND: Children account for a large portion of global influenza burden and transmission, and a better understanding of influenza in children is needed to improve prevention and control strategies. METHODS: To examine the incidence and transmission of influenza we conducted a prospective community-based study of children aged 0-14 years in Managua, Nicaragua, between 2011 and 2019. Participants were provided with medical care through study physicians and symptomatic influenza was confirmed by reverse-transcription polymerase chain reaction (RT-PCR). Wavelet analyses were used to examine seasonality. Generalized growth models (GGMs) were used to estimate effective reproduction numbers. RESULTS: From 2011 to 2019, 3016 children participated, with an average of ∼1800 participants per year and median follow-up time of 5 years per child, and 48.3% of the cohort in 2019 had been enrolled their entire lives. The overall incidence rates per 100 person-years were 14.5 symptomatic influenza cases (95% confidence interval [CI]: 13.9-15.1) and 1.0 influenza-associated acute lower respiratory infection (ALRI) case (95% CI: .8-1.1). Symptomatic influenza incidence peaked at age 9-11 months. Infants born during peak influenza circulation had lower incidence in the first year of their lives. The mean effective reproduction number was 1.2 (range 1.02-1.49), and we observed significant annual patterns for influenza and influenza A, and a 2.5-year period for influenza B. CONCLUSIONS: This study provides important information for understanding influenza epidemiology and informing influenza vaccine policy. These results will aid in informing strategies to reduce the burden of influenza.

The Spectrum of Influenza in Children.

BACKGROUND: Children constitute an important component of the influenza burden and community transmission, but the frequency of asymptomatic infection and post-influenza sequelae at the community level is poorly understood. METHODS: Two community-based prospective cohort studies (2011-2020, 2017-2020) and 1 case-ascertained study (2012-2017) were conducted in Managua, Nicaragua. Non-immunocompromised children aged 0-14 years with ≥1 influenza infections, determined by polymerase chain reaction and hemagglutination inhibition assay, were included. RESULTS: A total of 1272 influenza infections occurred in the household-based portion of the study. Influenza infection was asymptomatic in 84 (6.6%) infections, and the asymptomatic fraction increased with age (1.7%, 3.5%, and 9.1% for ages 0-1, 2-4, and 5-14, respectively; P < .001). Of asymptomatic children, 43 (51.2%) shed virus, compared to 1099 (92.5%) symptomatic children (P < .001). Also, 2140 cases of influenza occurred in the primary care portion of the study. Sequelae of influenza were rare, with the most common being pneumonia (52, 2.4%) and acute otitis media (71, 3.3%). A/H1N1 had higher age-adjusted odds of acute otitis media (odds ratio [OR] 1.99, 95% confidence interval [CI]: 1.14-3.48; P = .015) and hospitalization (OR 3.73, 95% CI: 1.68-8.67; P = .002) than A/H3N2. B/Victoria had higher age-adjusted odds of pneumonia (OR 10.99, 95% CI: 1.34-90.28; P = .026) than B/Yamagata. CONCLUSIONS: Asymptomatic influenza infection is much less common in children than adults, although viral shedding still occurs in asymptomatic children. Post-influenza sequelae are rare in children in the community setting, and virus strain may be important in understanding the risk of sequelae.

High Co-circulation of Influenza and Severe Acute Respiratory Syndrome Coronavirus 2.

In the first 2 years of the coronavirus disease 2019 pandemic, influenza transmission decreased substantially worldwide, meaning that health systems were not faced with simultaneous respiratory epidemics. In 2022, however, substantial influenza transmission returned to Nicaragua where it co-circulated with severe acute respiratory syndrome coronavirus 2, causing substantial disease burden.

Respiratory Syncytial Virus Incidence and Severity in a Community-Based Prospective Cohort of Children Aged 0-14 Years.

Background: Respiratory syncytial virus (RSV) is a substantial source of severe illnesses including acute lower respiratory infections (ALRIs) like pneumonia. However, its burden in older children remains less well understood. Methods: Using a community-based prospective cohort, we assessed the burden of symptomatic reverse-transcription polymerase chain reaction-confirmed RSV among Nicaraguan children aged 0-14 years from 2011 to 2016. ALRI was defined as physician diagnosis of pneumonia, bronchiolitis, bronchitis, or bronchial hyperreactivity. Results: Between 2011 and 2016, 2575 children participated in the cohort. Of these, 630 (24.5%) had at least 1 episode of symptomatic RSV and 194 (7.5%) had multiple episodes. Subtype was identified in 571 (69.3%) episodes with 408 (71.5%) RSV-A, 157 (27.5%) RSV-B, and 6 (1%) positive for both. Children aged <2 years displayed the highest incidence of symptomatic RSV, with 269.3 cases per 1000 person-years (95% confidence interval [CI], 242.1-299.5). Beyond 2 years, incidence (95% CI) of symptomatic RSV decreased rapidly: 145.6 (129.9-163.1), 37.9 (31.9-45.0), and 19.3 (14.9-25.0) cases per 1000 person-years among children aged 2-4, 5-9, and 10-14 years, respectively. Incidence of RSV-associated ALRI was highest in children aged <2 years (85.95 per 1000 person-years [95% CI, 71.30-103.61]): 2.1, 9.5, and 17.3 times that of participants aged 2-4, 5-9, and 10-14 years, respectively. Children <2 years old were significantly more likely to have an RSV-associated hospitalization (P < .001). Conclusions: There is a substantial burden of symptomatic and severe RSV in children. While older children did present with RSV, the rates of symptomatic and severe RSV decreased by as much as 95% beyond age 5.

Infection-induced immunity is associated with protection against SARS-CoV-2 infection, but not decreased infectivity during household transmission.

Background: Understanding the impact of infection-induced immunity on SARS-CoV-2 transmission will provide insight into the transition of SARS-CoV-2 to endemicity. Here we estimate the effects of prior infection induced immunity and children on SARS-CoV-2 transmission in households. Methods: We conducted a household cohort study between March 2020-June 2022 in Managua, Nicaragua where when one household member tests positive for SARS-CoV-2, household members are closely monitored for SARS-CoV-2 infection. Using a pairwise survival model, we estimate the association of infection period, age, symptoms, and infection-induced immunity with secondary attack risk. Results: Overall transmission occurred in 72.4% of households, 42% of household contacts were infected and the secondary attack risk was 13.0% (95% CI: 11.7, 14.6). Prior immunity did not impact the probability of transmitting SARS-CoV-2. However, participants with pre-existing infection-induced immunity were half as likely to be infected compared to naïve individuals (RR 0.53, 95% CI: 0.39, 0.72), but this reduction was not observed in children. Likewise, symptomatic infected individuals were more likely to transmit (RR 24.4, 95% CI: 7.8, 76.1); however, symptom presentation was not associated with infectivity of young children. Young children were less likely to transmit SARS-CoV-2 than adults. During the omicron era, infection-induced immunity remained protective against infection. Conclusions: Infection-induced immunity is associated with protection against infection for adults and adolescents. While young children are less infectious, prior infection and asymptomatic presentation did not reduce their infectivity as was seen in adults. As SARS-CoV-2 transitions to endemicity, children may become more important in transmission dynamics. Article summary: Infection-induced immunity protects against SARS-CoV-2 infection for adolescents and adults; however, there was no protection in children. Prior immunity in an infected individual did not impact the probability they will spread SARS-CoV-2 in a household setting.

High co-circulation of influenza and SARS-CoV-2.

In the first two years of the COVID-19 pandemic, influenza transmission decreased substantially worldwide meaning that health systems were not faced with simultaneous respiratory epidemics. In 2022, however, substantial influenza transmission returned to Nicaragua where it co-circulated with SARS-CoV-2 causing substantial disease burden.

Pediatric burden and seasonality of human metapneumovirus over 5 years in Managua, Nicaragua.

BACKGROUND: Human metapneumovirus (hMPV) is an important cause of pediatric respiratory infection. We leveraged the Nicaraguan Pediatric Influenza Cohort Study (NPICS) to assess the burden and seasonality of symptomatic hMPV infection in children. METHODS: NPICS is an ongoing prospective study of children in Managua, Nicaragua. We assessed children for hMPV infection via real-time reverse-transcription polymerase chain reaction (RT-PCR). We used classical additive decomposition analysis to assess the temporal trends, and generalized growth models (GGMs) were used to estimate effective reproduction numbers. RESULTS: From 2011 to 2016, there were 564 hMPV symptomatic infections, yielding an incidence rate of 5.74 cases per 100 person-years (95% CI 5.3, 6.2). Children experienced 3509 acute lower respiratory infections (ALRIs), of which 160 (4.6%) were associated with hMPV infection. Children under the age of one had 55% of all symptomatic hMPV infections (62/112) develop into hMPV-associated ALRIs and were five times as likely as children over one to have an hMPV-associated ALRI (rate ratio 5.5 95% CI 4.1, 7.4 p < 0.001). Additionally, symptomatic reinfection with hMPV was common. In total, 87 (15%) of all observed symptomatic infections were detected reinfections. The seasonality of symptomatic hMPV outbreaks varied considerably. From 2011 to 2016, four epidemic periods were observed, following a biennial seasonal pattern. The mean ascending phase of the epidemic periods were 7.7 weeks, with an overall mean estimated reproductive number of 1.2 (95% CI 1.1, 1.4). CONCLUSIONS: Symptomatic hMPV infection was associated with substantial burden among children in the first year of life. Timing and frequency of symptomatic hMPV incidence followed biennial patterns.

SARS-CoV-2 and endemic coronaviruses: Comparing symptom presentation and severity of symptomatic illness among Nicaraguan children.

It has been proposed that as SARS-CoV-2 transitions to endemicity, children will represent the greatest proportion of SARS-Co-V-2 infections as they currently do with endemic coronavirus infections. While SARS-CoV-2 infection severity is low for children, it is unclear if SARS-CoV-2 infections are distinct in symptom presentation, duration, and severity from endemic coronavirus infections in children. We compared symptom risk and duration of endemic human coronavirus (HCoV) infections from 2011-2016 with SARS-CoV-2 infections from March 2020-September 2021 in a Nicaraguan pediatric cohort. Blood samples were collected from study participants annually in February-April. Respiratory samples were collected from participants that met testing criteria. Blood samples collected in were tested for SARS-CoV-2 antibodies and a subset of 2011-2016 blood samples from four-year-old children were tested for endemic HCoV antibodies. Respiratory samples were tested for each of the endemic HCoVs from 2011-2016 and for SARS-CoV-2 from 2020-2021 via rt-PCR. By April 2021, 854 (49%) cohort participants were ELISA positive for SARS-CoV-2 antibodies. Most participants had antibodies against one alpha and one beta coronavirus by age four. We observed 595 symptomatic endemic HCoV infections from 2011-2016 and 121 symptomatic with SARS-CoV-2 infections from March 2020-September 2021. Symptom presentation of SARS-CoV-2 infection and endemic coronavirus infections were very similar, and SARS-CoV-2 symptomatic infections were as or less severe on average than endemic HCoV infections. This suggests that, for children, SARS-CoV-2 may be just another endemic coronavirus. However, questions about the impact of variants and the long-term effects of SARS-CoV-2 remain.