The impact of the 2009 H1N1 influenza pandemic on pediatric patients with sickle cell disease

A child with sickle cell disease admitted with coronavirus disease 2019 pneumonia and acute chest syndrome in pediatric intensive care unit: A case report

Management of sickle cell disease complications in the setting of the coronavirus disease 2019 (COVID-19) pandemic is complicated with little published pediatric data. We report the first documented case of a 9-year-old boy with sickle cell disease, presenting with fever, cough, and shortness of breath, diagnosed to have acute chest syndrome and coronavirus disease 2019 (COVID-19) pneumonia with inflammatory storm requiring ventilation, exchange blood transfusion, immunomodulatory agents, and prophylactic anticoagulation. The patient responded satisfactorily to the management of the acute illness and was found to be well at the next visit to the pediatric hematology outpatient department following hospital discharge.

Risk factors for acute chest syndrome among children with sickle cell anemia hospitalized for vaso-occlusive crises

Sickle cell anemia (SCA) is a globally prevalent inherited condition, with acute chest syndrome (ACS) being one of its most severe complications. ACS frequently leads to hospitalization, requires intensive care unit (ICU) admission, and can even result in death. This study aimed to discern the early indicators of impending ACS in children with SCA who were initially hospitalized due to painful vaso-occlusive crises (VOC). This was a retrospective, case‒control investigation of 120 patients aged 1-14 years seen at the King Saud Medical City in Riyadh, Saudi Arabia from January 2021 to December 2022. Patients were classified into cases and controls: those who developed and did not develop ACS during hospital stay, respectively. Demographic factors, laboratory results, vital and clinical signs, and treatment protocols were compared between these groups. The following were significant predictors of impending ACS: previous diagnosis of asthma, history of ACS, recent upper respiratory tract symptoms prior to admission, and need for a blood transfusion within the first 24 h of admission due to a drop in hemoglobin levels. Further regression analysis indicated that elevated steady-state mean corpuscular volume, leukocyte count, total bilirubin, and an increased absolute neutrophil count level 24 h after admission also foreshadowed impending ACS among patients admitted for VOC. The location of pain was also significant; the incidence of ACS was higher in patients with back pain, but lower in those with pain confined to the limbs. The ACS group had a longer average duration of hospital stay compared to those with VOC alone, (7.6 vs. 5.8 days). Among patients initially admitted for VOC, 15.7% were diagnosed with ACS. Most ACS cases were managed with transfusions and antibiotics, and nearly one-third of patients needed admission to an ICU or a high-dependency area.

COVID-19 outcomes in patients with sickle cell disease and sickle cell trait compared with individuals without sickle cell disease or trait: a systematic review and meta-analysis

Background

Clinical manifestations and severity of SARS-CoV-2 infection in individuals with sickle cell disease (SCD) and sickle cell trait (SCT) are not well understood yet.

Methods

We performed a systematic review and meta-analysis to assess COVID-19 outcomes in individuals with SCD or SCT compared to individuals without sickle cell disease or trait. An electronic search on PubMed, Embase, and Cochrane Library was performed on August 3, 2023. Two authors (IFM and ISP) independently screened (IFM and ISP) and extracted data (IFM and ILC) from included studies. Main exclusion criterion was the absence of the non-SCD/SCT group. Exposure effects for binary endpoints were compared using pooled odds ratio (OR) with 95% confidence intervals (CI). I2 statistics was used to assess the heterogeneity and DerSimonian and Laird random-effects models were applied for all analyses to minimize the impact of differences in methods and outcomes definitions between studies. The overall quality of evidence was assessed using the GRADE system. Review Manager 5.4 and R software (v4.2.2) were used for statistical analyses. Registered with PROSPERO, CRD42022366015.

Findings

Overall, 22 studies were included, with a total of 1892 individuals with SCD, 8677 individuals with SCT, and 1,653,369 individuals without SCD/SCT. No difference in all-cause mortality was seen between SCD/SCT and non-SCD/SCT (OR 1.18; 95% CI 0.78-1.77; p = 0.429; I2 = 82%). When considering only studies adjusted for confounders (8 studies), patients with SCD/SCT were shown to be at increased risk of death (OR 1.86; 95% CI 1.30-2.66; p = 0.0007; I2 = 34%). No significant difference was seen between individuals with SCD and SCT (p = 0.863). The adjusted for confounders analysis for hospitalisation revealed higher rates for the SCD (OR 5.44; 95% CI 1.55-19.13; p = 0.008; I2 = 97%) and the SCT groups (OR 1.31; 95% CI 1.10-1.55; p = 0.002; I2 = 0) compared to the non-SCD/SCT population. Moreover, it was significantly higher for the SCD group (test for subgroup difference; p = 0.028).

Interpretation

Our findings suggest that patients with SCD or SCT may present with a higher mortality and hospitalisation rates due to COVID-19 infection.

Funding

None.

From H1N1 to COVID-19: What we have seen in children with hemoglobinopathies

This work aimed to better understand the impact of pandemics of respiratory viruses on children with hemoglobinopathies through a comprehensive review of the literature. MEDLINE, SCIELO, LILACS, and PUBMED were used as data sources to find articles without time period restrictions. Previous observations suggest that patients with hemoglobinopathies are a group especially susceptible to the complications of viral respiratory infections, with greater morbidity and mortality related to them. Within this context, this review found that, during the 2009 H1N1 pandemic, the risk of hospitalization in children and adults increased, especially in patients with a history of complications such as acute chest syndrome. In addition, the Coronavirus Disease 2019 (COVID-19) pandemic appears to have less repercussion among children with hemoglobinopathies compared to adults, similar to what is seen in the general population. In the H1N1 pandemic, patients with hemoglobinopathies behaved as a group more susceptible to complications, with increased morbidity and mortality. However, for COVID-19, the existing data to date on these patients do not show the same clinical impact. Thus, although these children deserve attention in case of infection due to their potential risks, they seem to have a favorable evolution.

A review on how to do hematology consults during COVID-19 pandemic

The ongoing COVID-19 pandemic is the most trending and talked topic across the World. From its point of origin in Wuhan, China to clinical laboratory at NIH, a mere six-month-old SARS-CoV-2 virus is keeping the clinicians, and scientists busy at various fronts. However, COVID-19 is an emerging and evolving disease and each day brings in more data, new figures, and findings from the field of clinical practice. The role of hematologists has been increasingly recognized during the current pandemic because of several reasons. Most important of them are the characteristic hematological findings of COVID-19 patients that also have prognostic implications and that were not seen in other viral infections. The treatment of hematological complications in COVID-19 patients is very challenging given the critical care setting. There are interim and limited guidelines thus far due to the novelty of the disease. As this remains to be a quite fluid situation, all the appropriate medical societies including the major hematology bodies are proposing initial and interim guidelines (e.g. ASH guideline). This puts a hematologist on consult service in a dubious position where, he/she must tailor the recommendations on case to case basis. The purpose of this review is to provide the background context about the impact of COVID-19 on the blood system and to summarize the current interim guidelines to manage the associated hematological issues in COVID-19 infection.

Clinical predictors of poor outcomes in patients with sickle cell disease and COVID-19 infection

SCD patients with COVID-19 display a broad range of severity, with a higher case fatality than the non-SCD population (10.9% vs 3.3%).

Older patients not treated with hydroxyurea with end organ damage who present with acute kidney injury, and elevated LDH and D-dimer level are at higher risk of death.

We aimed to identify predictors of outcomes and survival in patients living in 4 major metropolitan areas who had sickle cell disease (SCD) and COVID-19 to inform best approaches to prevention and care. Data were collected at baseline and during the clinical course in SCD patients diagnosed with COVID-19 in four COVID-19 epicenters. Patients were followed up posthospital discharge for up to 3 months. Of sixty-six SCD patients with COVID-19, fifty patients (75%) required hospitalization, and seven died (10.6%). Patients with preexisting kidney disease (chronic kidney disease) were more likely to be hospitalized. The most common presenting symptom was vaso-occlusive pain. Acute chest syndrome occurred in 30 (60%) of the 50 hospitalized patients and in all who died. Older age and histories of pulmonary hypertension, congestive heart failure, chronic kidney disease, and stroke were more prevalent in patients who died, as were higher creatinine, lactate dehydrogenase, and D-dimer levels. Anticoagulation use while inpatient was twice less common in patients who died. All deaths occurred in individuals not taking hydroxyurea or any other SCD-modifying therapy. Patients with SCD and COVID-19 exhibited a broad range of disease severity. We cannot definitively state that the overall mortality is higher in patients with SCD, although our case fatality rate was ∼10% compared with ∼3% in the general population, despite a median age of 34 years. Individuals with SCD aged >50 years, with preexisting cardiopulmonary, renal disease, and/or stroke not receiving hydroxyurea, who present with high serum creatinine, lactate dehydrogenase, and D-dimer levels, are at higher risk of death, irrespective of genotype or sex.

Respiratory Viral Infections in Sickle Cell Anemia: Special Emphasis on H1N1 Co-infection

Objectives

Patients with sickle cell anemia (SCA) are immunocompromised and at an increased risk of developing infections. Our aim was to establish the clinical, laboratory, and radiological manifestations of respiratory viral infections in SCA at Sultan Qaboos University Hospital (SQUH), Oman and assess its impact on disease morbidity and mortality, with special emphasis on H1N1.

Methods

We undertook a retrospective study in SCA patients with respiratory viral infections following up at the hematology department at SQUH. We collected demographic data and clinical, radiological, and laboratory parameters.

Results

In 84 SCA patients with 109 admission episodes for vaso-occlusive crisis (VOC), molecular diagnostic techniques confirmed 125 respiratory viral infections. Rhinovirus was the most prevalent infection (35.8%), whereas H1N1 virus infection was seen only in 10.1%. Laboratory investigations revealed a significant fall in mean hemoglobin levels, mean white blood cell, and platelet counts from baseline, whereas there was a significant rise in the mean lymphocyte and retic count, serum lactate dehydrogenase, and C-reactive protein levels during infective episodes (p < 0.050, Wilcoxon signed rank test). One-third (32.1%) of the VOC episodes progressed to acute chest syndrome (ACS), but in the H1N1 cohort, only two episodes of ACS was seen (18.2%).

Conclusions

Rhinovirus was the commonest respiratory virus infections in SCA patients, whereas parainfluenza 3 was associated with a significant adverse outcome. H1N1 was associated with a mild course. ACS was seen in approximately one-third of this group of patients.

Respiratory pathogens and acute chest syndrome in children with sickle cell disease

BACKGROUND

Acute chest syndromes (ACS) may be associated with upper respiratory tract infections, but the epidemiology of viral and intracellular respiratory pathogens in children with sickle cell disease (SCD) is not precisely known. The aim of this study was to describe the epidemiology of viral and intracellular respiratory pathogens in children with SCD presenting with fever and/or ACS.

MATERIALS AND METHODS

An observational, prospective, single-centre cohort study with nested case-control analysis was conducted on children with SCD admitted from October 2016 to October 2017 for fever and/or ACS to the paediatric department of Robert Debré university hospital, Paris, France. They were screened for 20 respiratory pathogens by a multiplex PCR in the nasopharynx (FilmArray).

RESULTS

We included 101 children. M/F sex ratio of 0.45. The median age was 3.2 years (IQR: 1.4-8.2). At least one pathogen was isolated in 67 patients (67%). The most frequent viruses were as follows: rhinovirus (n=33), adenovirus (n=14), respiratory syncytial virus (n=13) and parainfluenza viruses (n=11). Mycoplasma pneumoniae was detected in one case. Twenty-three (23%) presented with or developed ACS. A nested case-control analysis was performed, after pairing ACS with non-ACS children for age and inclusion period. There was no statistical association between any viral detection or multiple viral infection, and ACS (p=0.51) even though parainfluenza viruses were twice as common in ACS.

CONCLUSIONS

Viral detection in febrile children with SCD is frequent, but its association with ACS was not demonstrated. In this study, M. pneumoniae was rare in young children with SCD experiencing ACS.

Influenza vaccine effectiveness and disease burden in children and adolescents with sickle cell disease: 2012-2017

BACKGROUND

Data are limited on the burden of influenza and seasonal influenza vaccine effectiveness (VE) in children with sickle cell disease (SCD).

METHODS

We used a prospectively collected clinical registry of SCD patients 6 months to 21 years of age to determine the influenza cases per 100 patient-years, vaccination rates, and a test-negative case-control study design to estimate influenza VE against medically attended laboratory-confirmed influenza infection. Influenza-positive cases were randomly matched to test-negative controls on age and influenza season in 1:1 ratio. We used adjusted logistic regression models to compare odds ratio (OR) of vaccination in cases to controls. We calculated VE as [100% × (1 - adjusted OR)] and computed 95% confidence intervals (CIs) around the estimate.

RESULTS

There were 1037 children with SCD who were tested for influenza, 307 children (29.6%) had at least one influenza infection (338 infections, incidence rate 3.7 per 100 person-years; 95% CI, 3.4-4.1) and 56.2% of those tested received annual influenza vaccine. Overall VE pooled over five seasons was 22.3% (95% CI, -7.3% to 43.7%). Adjusted VE estimates ranged from 39.7% (95% CI, -70.1% to 78.6%) in 2015/2016 to -5.9% (95% CI, -88.4% to 40.4%) in the 2016/17 seasons. Influenza VE varied by age and was highest in children 1-5 years of age (66.6%; 95% CI, 30.3-84.0). Adjusted VE against acute chest syndrome during influenza infection was 39.4% (95% CI, -113.0 to 82.8%).

CONCLUSIONS

Influenza VE in patients with SCD varies by season and age. Multicenter prospective studies are needed to better establish and monitor influenza VE among children with SCD.

Challenges in the Management of Sickle Cell Disease During SARS-CoV-2 Pandemic

The management of sickle cell disease (SCD) and its complications in the COVID-19 era is very challenging. The recurrent sickling process in SCD causes tissue hypoxemia and micro-infarcts, resulting in end organ damage. Since the outbreak of SARS-CoV-2 pandemic, little data has been published about SCD concerning clinical presentation with COVID-19 and management. Hydroxyurea has been the cornerstone of management in children and adults with SCD, with evidence of its effect on controlling end organ damage. There are several anti-sickling drugs that have been approved recently that might have an additive value toward the management of SCD and its complications. The role of simple and exchange transfusions is well established and should always be considered in the management of various complications. The value of convalescent plasma has been demonstrated in small case series, but large randomized controlled studies are still awaited. Immunomodulatory agents may play a role in reducing the damaging effects of cytokines storm that contributes to the morbidity and mortality in advanced cases. Prophylactic anticoagulation should be considered in every management protocol because SCD and COVID-19 are thrombogenic conditions. Management proposals of different presentations of patients with SCD and COVID-19 are outlined.

Children with sickle cell disease migrating to the United States from sub-Saharan Africa

Sickle cell disease (SCD) is an inherited red blood cell disorder that occurs worldwide and results in significant morbidity and mortality. In addition to affected children who are born in the US, an increasing number of children with SCD are migrating to the US with their families or through international adoption. Children arriving as immigrants or refugees have unique medical and psychosocial challenges that require a multidisciplinary team approach which takes into account the family's primary language, culture, and health beliefs. This review focuses on the special challenges for children with SCD who emigrate from sub-Saharan Africa to the US.

Influenza Vaccination Protects Against Pandemic H1N1 Infection in Sickle Cell Disease Mice

Influenza infection is associated with enhanced pathology in individuals with sickle cell disease (SCD). Despite being a high priority group for annual influenza vaccination, little is known about long-term responses to influenza vaccination in this patient population. To model flu vaccination, we inoculated SCD and wild type (WT) littermate mice with the seasonal flu vaccine [containing pandemic H1N1 (pH1N1) antigen], bled the mice before and after vaccination, and intranasally challenged them with a high dose (400 PFU) of pH1N1 12 weeks later. Both WT and SCD mice were fully protected from infection, and anti-influenza immunoglobulin G titers were significantly elevated in both groups after vaccination. It appears that flu vaccination is effective in SCD mice and our data support the clinical practice of regular flu vaccination in SCD patients.

Sickle Cell Disease and Acute Chest Syndrome: Epidemiology, Diagnosis, Management, Outcomes

Sickle cell disease (SCD) is one of the most common monogenetic diseases worldwide and is attributable to significant morbidity and mortality. Mutations causing abnormal hemoglobin formation in this disease lead to structural abnormalities and cumulative damage to the cellular membrane of sickled erythrocytes. Polymerization and aggregation of these cells within the microvasculature results in severe vaso-occlusive pain crisis, chronic hemolytic anemia, and multiorgan pathology in patients. Pulmonary manifestations of SCD, including the acute chest syndrome (ACS), are a leading cause of hospitalization and mortality. ACS is a severe type of acute lung injury, defined as the development of a new pulmonary infiltrate, involving at least one complete lung segment, that is accompanied by fever, chest pain, tachypnea, wheezing, or cough in a patient with SCD. The etiology of ACS is multifactorial, with the most common mechanisms including infection, fat and bone marrow embolism, and direct microvascular vaso-occlusion. Despite recent advances in our understanding of the pathogenesis and clinical management of ACS in SCD, patient outcomes remain unacceptably poor. This chapter reviews the epidemiology, diagnosis, management, and outcomes of ACS in SCD. Proper screening, a high index of clinical suspicion, and immediate clinical care for this condition are pivotal for improving patient outcomes.

Potential Impact of Co-Infections and Co-Morbidities Prevalent in Africa on Influenza Severity and Frequency: A Systematic Review

Infectious diseases and underlying medical conditions common to Africa may affect influenza frequency and severity. We conducted a systematic review of published studies on influenza and the following co-infections or co-morbidities that are prevalent in Africa: dengue, malaria, measles, meningococcus, Pneumocystis jirovecii pneumonia (PCP), hemoglobinopathies, and malnutrition. Articles were identified except for influenza and PCP. Very few studies were from Africa. Sickle cell disease, dengue, and measles co-infection were found to increase the severity of influenza disease, though this is based on few studies of dengue and measles and the measles study was of low quality. The frequency of influenza was increased among patients with sickle cell disease. Influenza infection increased the frequency of meningococcal disease. Studies on malaria and malnutrition found mixed results. Age-adjusted morbidity and mortality from influenza may be more common in Africa because infections and diseases common in the region lead to more severe outcomes and increase the influenza burden. However, gaps exist in our knowledge about these interactions.

Durable immune response to inactivated H1N1 vaccine is less likely in children with sickle cell anemia receiving chronic transfusions

BACKGROUND

Defects in the immune system may affect vaccine responsiveness. Because of the splenic hypofunction and abnormal opsonic activity, it was unknown whether patients with sickle cell disease (SCD) would respond appropriately to H1N1 vaccination. The objective of this study was to assess seroprotective post-vaccine H1N1 antibody response in children with SCD.

PROCEDURE

Serum antibody titers were measured by hemagglutination inhibition and microneutralization (MN) assays. Correlations were established between clinical and treatment parameters and immune response.

RESULTS

Twenty-nine of 38 (76.3%) subjects (mean age 11 ± 5.4 years) had durable protective antibody titers 8 ± 1.6 months (range 5-12 months) post-vaccination. Lessened immune response was not associated with time interval from vaccination, splenectomy, or hydroxyurea treatment. Lack of antibody response was associated with age less than 3 years and treatment with chronic transfusions. Of the nine non-responders, seven were on chronic transfusions (39% unresponsiveness rate in the transfused group). The difference in the number of patients with seropositivity between the non-transfused and the transfused groups was statistically significant (P = 0.039).

CONCLUSIONS

Most subjects were able to mount an influenza-specific antibody response against the inactivated H1N1 vaccine. Similar to the general population, children less than 3 years were less likely to respond. In addition, patients on chronic transfusions were less likely to respond when compared to non-transfused children. Clinicians should be aware of the possibility of decreased vaccine response in patients with SCD on chronic transfusions. We postulate that transfusion-related immunomodulation (TRIM) may be related to decreased response.