Cost-Effectiveness/Cost-Benefit Analysis of Newborn Screening for Severe Combined Immune Deficiency in Washington State

A Unique Comprehensive Model to Screen Newborns for Severe Combined Immunodeficiency-An Ontario Single-Centre Experience Spanning 2013-2023

BACKGROUND

Severe combined immunodeficiency (SCID) is a life-threatening genetic disorder caused by critical defects of the immune system. Almost all cases are lethal if not treated within the first two years of life. Early diagnosis and intervention are thus essential for improving patient outcomes. In 2013, Ontario became the first Canadian province to perform newborn screening (NBS) for SCID by T cell receptor excision circles (TRECs) analysis, a surrogate marker of thymic function and lymphocyte maturation.

METHODS

This retrospective study reports on nearly 10 years of NBS for SCID at a quaternary referral centre.

RESULTS

From August 2013 to April 2023, our centre's densely populated catchment area flagged 162 newborns with low TRECs levels, including 10 cases with SCID. Follow-up revealed other causes of low TRECs, including non-SCID T cell lymphopenia (secondary/reversible or idiopathic causes, and syndromic conditions) and prematurity. A small number of cases with normal repeat TRECs levels and/or T cell subsets were also flagged. Province-wide data from around this period revealed at least 24 diagnosed cases of SCID or Leaky SCID.

CONCLUSIONS

This is the first report of NBS outcomes in a Canadian province describing the causative genetic defects, and the non-SCID causes of a positive NBS for SCID.

Paving the way in implementation of SCID newborn screening in developing nations: feasibility study and strategies to move forward in Malaysia

Early diagnosis and effective management of Primary immunodeficiency diseases (PIDs), particularly severe combined immunodeficiency (SCID), play a crucial role in minimizing associated morbidities and mortality. Newborn screening (NBS) serves as a valuable tool in facilitating these efforts. Timely detection and diagnosis are essential for swiftly implementing isolation measures and ensuring prompt referral for definitive treatment, such as allogeneic hematopoietic stem cell transplantation. The utilization of comprehensive protocols and screening assays, including T cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC), is essential in facilitating early diagnosis of SCID and other PIDs, but their successful application requires clinical expertise and proper implementation strategy. Unfortunately, a notable challenge arises from insufficient funding for the treatment of PIDs. To address these issues, a collaborative approach is imperative, involving advancements in technology, a well-functioning healthcare system, and active engagement from stakeholders. The integration of these elements is essential for overcoming the existing challenges in NBS for PIDs. By fostering synergy between technology providers, healthcare professionals, and governmental stakeholders, we can enhance the efficiency and effectiveness of early diagnosis and intervention, ultimately improving outcomes for individuals with PIDs.

Benefits and harms of antenatal and newborn screening programmes in health economic assessments: the VALENTIA systematic review and qualitative investigation

Background

Health economic assessments are used to determine whether the resources needed to generate net benefit from an antenatal or newborn screening programme, driven by multiple benefits and harms, are justifiable. It is not known what benefits and harms have been adopted by economic evaluations assessing these programmes and whether they omit benefits and harms considered important to relevant stakeholders.

Objectives

(1) To identify the benefits and harms adopted by health economic assessments in this area, and to assess how they have been measured and valued; (2) to identify attributes or relevance to stakeholders that ought to be considered in future economic assessments; and (3) to make recommendations about the benefits and harms that should be considered by these studies.

Design

Mixed methods combining systematic review and qualitative work.

Systematic review methods

We searched the published and grey literature from January 2000 to January 2021 using all major electronic databases. Economic evaluations of an antenatal or newborn screening programme in one or more Organisation for Economic Co-operation and Development countries were considered eligible. Reporting quality was assessed using the Consolidated Health Economic Evaluation Reporting Standards checklist. We identified benefits and harms using an integrative descriptive analysis and constructed a thematic framework.

Qualitative methods

We conducted a meta-ethnography of the existing literature on newborn screening experiences, a secondary analysis of existing individual interviews related to antenatal or newborn screening or living with screened-for conditions, and a thematic analysis of primary data collected with stakeholders about their experiences with screening.

Results

The literature searches identified 52,244 articles and reports, and 336 unique studies were included. Thematic framework resulted in seven themes: (1) diagnosis of screened for condition, (2) life-years and health status adjustments, (3) treatment, (4) long-term costs, (5) overdiagnosis, (6) pregnancy loss and (7) spillover effects on family members. Diagnosis of screened-for condition (115, 47.5%), life-years and health status adjustments (90, 37.2%) and treatment (88, 36.4%) accounted for most of the benefits and harms evaluating antenatal screening. The same themes accounted for most of the benefits and harms included in studies assessing newborn screening. Long-term costs, overdiagnosis and spillover effects tended to be ignored. The wide-reaching family implications of screening were considered important to stakeholders. We observed good overlap between the thematic framework and the qualitative evidence.

Limitations

Dual data extraction within the systematic literature review was not feasible due to the large number of studies included. It was difficult to recruit healthcare professionals in the stakeholder's interviews.

Conclusions

There is no consistency in the selection of benefits and harms used in health economic assessments in this area, suggesting that additional methods guidance is needed. Our proposed thematic framework can be used to guide the development of future health economic assessments evaluating antenatal and newborn screening programmes.

Study registration

This study is registered as PROSPERO CRD42020165236.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR127489) and is published in full in Health Technology Assessment; Vol. 28, No. 25. See the NIHR Funding and Awards website for further award information.

Rare Disease, Advocacy and Justice: Intersecting Disparities in Research and Clinical Care

Rare genetic diseases collectively impact millions of individuals in the United States. These patients and their families share many challenges including delayed diagnosis, lack of knowledgeable providers, and limited economic incentives to develop new therapies for small patient groups. As such, rare disease patients and families often must rely on advocacy, including both self-advocacy to access clinical care and public advocacy to advance research. However, these demands raise serious concerns for equity, as both care and research for a given disease can depend on the education, financial resources, and social capital available to the patients in a given community. In this article, we utilize three case examples to illustrate ethical challenges at the intersection of rare diseases, advocacy and justice, including how reliance on advocacy in rare disease may drive unintended consequences for equity. We conclude with a discussion of opportunities for diverse stakeholders to begin to address these challenges.

Efficient screening strategies for severe combined immunodeficiencies in newborns

INTRODUCTION

Severe combined immunodeficiency (SCID) is one of the most severe forms of inborn errors of immunity (IEI), affecting both cellular and humoral immunity. Without curative treatment such as hematopoietic stem cell transplantation or gene therapy, affected infants die within the first year of life. Due to the severity of the disease, asymptomatic status early in life, and improved survival in the absence of pretransplant infections, SCID was considered a suitable candidate for newborn screening (NBS).

AREAS COVERED

Many countries have introduced SCID screening based on T-cell receptor excision circle (TREC) detection in their NBS programs. Screening an entire population is a radical departure from previous paradigms in the field of immunology. Efficient screening strategies are cost-efficient and balance high sensitivity while preventing high numbers of referrals. NBS for SCID is accompanied by (actionable) secondary findings, but many NBS programs have optimized their screening strategy by adjusting algorithms or including second-tier tests. Harmonization of screening terminology is of great importance for international shared learning.

EXPERT OPINION

The expansion of NBS is driven by the development of new test modalities and treatment options. In the near future, other techniques such as next-generation sequencing will pave the way for NBS of other IEI. Exciting times await for population-based screening programs.

Genomic-Based Newborn Screening for Inborn Errors of Immunity: Practical and Ethical Considerations

Inborn errors of immunity (IEI) are a group of over 450 genetically distinct conditions associated with significant morbidity and mortality, for which early diagnosis and treatment improve outcomes. Newborn screening for severe combined immunodeficiency (SCID) is currently underway in several countries, utilising a DNA-based technique to quantify T cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC). This strategy will only identify those infants with an IEI associated with T and/or B cell lymphopenia. Other severe forms of IEI will not be detected. Up-front, first-tier genomic-based newborn screening has been proposed as a potential approach by which to concurrently screen infants for hundreds of monogenic diseases at birth. Given the clinical, phenotypic and genetic heterogeneity of IEI, a next-generation sequencing-based newborn screening approach would be suitable. There are, however, several ethical, legal and social issues which must be evaluated in detail prior to adopting a genomic-based newborn screening approach, and these are discussed herein in the context of IEI.

Newborn screening for genetic disorders: Current status and prospects for the future

Newborn screening (NBS) is a public health service aimed at identifying infants with severe genetic disorders, thus providing effective treatment early enough to prevent or ameliorate the onset of symptoms. Current NBS uses biochemical analysis of dried blood spots, predominately with time-resolved fluorescence immunoassay and tandem mass spectrometry, which produces some false positives and false negatives. The application of enzymatic activity-based testing technology provides a reliable screening method for some disorders. Genetic testing is now commonly used for secondary or confirmatory testing after a positive result in some NBS programs. Recently, next-generation sequencing (NGS) has emerged as a robust tool that enables large panels of genes to be scanned together rapidly. Rapid advances in NGS emphasize the potential for genomic sequencing to improve NBS programs. However, some challenges still remain and require solution before this is applied for population screening.

Population-based screening of newborns: Findings from the newborn screening expansion study (part two)

Rapid advances in genomic technologies to screen, diagnose, and treat newborns will significantly increase the number of conditions in newborn screening (NBS). We previously identified four factors that delay and/or complicate NBS expansion: 1) variability in screening panels persists; 2) the short duration of pilots limits information about interventions and health outcomes; 3) recent recommended uniform screening panel (RUSP) additions are expanding the definition of NBS; and 4) the RUSP nomination and evidence review process has capacity constraints. In this paper, we developed a use case for each factor and suggested how model(s) could be used to evaluate changes and improvements. The literature on models was reviewed from a range of disciplines including system sciences, management, artificial intelligence, and machine learning. The results from our analysis highlighted that there is at least one model which could be applied to each of the four factors that has delayed and/or complicate NBS expansion. In conclusion, our paper supports the use of modeling to address the four challenges in the expansion of NBS.

Modelling the Cost-Effectiveness and Budget Impact of a Newborn Screening Program for Spinal Muscular Atrophy and Severe Combined Immunodeficiency

Spinal muscular atrophy (SMA) and severe combined immunodeficiency (SCID) are rare, inherited genetic disorders with severe mortality and morbidity. The benefits of early diagnosis and initiation of treatment are now increasingly recognized, with the most benefits in patients treated prior to symptom onset. The aim of the economic evaluation was to investigate the costs and outcomes associated with the introduction of universal newborn screening (NBS) for SCID and SMA, by generating measures of cost-effectiveness and budget impact. A stepwise approach to the cost-effectiveness analyses by decision analytical models nested with Markov simulations for SMA and SCID were conducted from the government perspective. Over a 60-year time horizon, screening every newborn in the population and treating diagnosed SCID by early hematopoietic stem cell transplantation and SMA by gene therapy, would result in 95 QALYs gained per 100,000 newborns, and result in cost savings of USD 8.6 million. Sensitivity analysis indicates 97% of simulated results are considered cost-effective against commonly used willingness-to-pay thresholds. The introduction of combined NBS for SCID and SMA is good value for money from the long-term clinical and economic perspectives, representing a cost saving to governments in the long-term, as well as improving and saving lives.

Economic Evaluation of Newborn Screening for Severe Combined Immunodeficiency

Evidence on the cost-effectiveness of newborn screening (NBS) for severe combined immunodeficiency (SCID) in the Australian policy context is lacking. In this study, a pilot population-based screening program in Australia was used to model the cost-effectiveness of NBS for SCID from the government perspective. Markov cohort simulations were nested within a decision analytic model to compare the costs and quality-adjusted life-years (QALYs) over a time horizon of 5 and 60 years for two strategies: (1) NBS for SCID and treat with early hematopoietic stem cell transplantation (HSCT); (2) no NBS for SCID and treat with late HSCT. Incremental costs were compared to incremental QALYs to calculate the incremental cost-effectiveness ratios (ICER). Sensitivity analyses were performed to assess the model uncertainty and identify key parameters impacting on the ICER. In the long-term over 60 years, universal NBS for SCID would gain 10 QALYs at a cost of US $0.3 million, resulting in an ICER of US$33,600/QALY. Probabilistic sensitivity analysis showed that more than half of the simulated ICERs were considered cost-effective against the common willingness-to-pay threshold of A$50,000/QALY (US$35,000/QALY). In the Australian context, screening for SCID should be introduced into the current NBS program from both clinical and economic perspectives.

Economic Evaluation of Different Screening Strategies for Severe Combined Immunodeficiency Based on Real-Life Data

Although several countries have adopted severe combined immunodeficiency (SCID) into their newborn screening (NBS) program, other countries are still in the decision process of adding this disorder in their program and finding the appropriate screening strategy. This decision may be influenced by the cost(-effectiveness) of these screening strategies. In this study, the cost(-effectiveness) of different NBS strategies for SCID was estimated based on real-life data from a prospective implementation study in the Netherlands. The cost of testing per child for SCID was estimated at EUR 6.36. The cost of diagnostics after screen-positive results was assessed to vary between EUR 985 and 8561 per child dependent on final diagnosis. Cost-effectiveness ratios varied from EUR 41,300 per QALY for the screening strategy with T-cell receptor excision circle (TREC) ≤ 6 copies/punch to EUR 44,100 for the screening strategy with a cut-off value of TREC ≤ 10 copies/punch. The analysis based on real-life data resulted in higher costs, and consequently in less favorable cost-effectiveness estimates than analyses based on hypothetical data, indicating the need for verifying model assumptions with real-life data. The comparison of different screening strategies suggest that strategies with a lower number of referrals, e.g., by distinguishing between urgent and less urgent referrals, are favorable from an economic perspective.

Economic burden of congenital athymia in the United States for patients receiving supportive care during the first 3 years of life

AIMS

Congenital athymia is an ultra-rare pediatric condition characterized by the lack of thymus in utero and the naïve T cells critical for infection defense and immune regulation. Patients with congenital athymia receive supportive care to minimize and treat infections, autoimmune phenomena, and autologous graft-versus-host disease (aGVHD) manifestations, but historically, die within the first 3 years of life with supportive care only. We estimated the healthcare resource utilization and economic burden of supportive care over patients' first 3 years of life in the United States.

METHODS

A medical chart audit by the treating physician was used to collect patient data from birth to age 3 on clinical manifestations associated with congenital athymia (clinical manifestations due to underlying syndromic conditions excluded). Using costs and charges from publicly available sources, the total economic burden of direct medical costs and charges for the first 3 years of life (considered "lifetime" for patients receiving supportive care) and differences in economic burden between patients with higher and lower inpatient hospitalization durations were estimated.

RESULTS

All patients (n = 10) experienced frequent infections and aGVHD manifestations; 40% experienced ≥1 episode of sepsis, and 20% had recurrent sepsis episodes annually. The estimated mean 3-year economic burden per patient was US$5,534,121 (2020 US dollars). The annual mean inpatient hospitalization duration was 150.6 days. Inpatient room charges accounted for 79% of the economic burden, reflecting the high costs of specialized care settings required to prevent infection, including isolation. Patients with high inpatient utilization (n = 5; annual mean inpatient hospitalization duration, 289.6 days) had an estimated 3-year economic burden of US$9,926,229.

LIMITATIONS

The total economic burden may not be adequately represented due to underestimation of some direct costs or overestimation of others.

CONCLUSIONS

Current treatment of patients with congenital athymia (supportive care) presents a high economic burden to the healthcare system.

The Methodological Quality and Challenges in Conducting Economic Evaluations of Newborn Screening: A Scoping Review

INTRODUCTION

Cost-effectiveness (CEA) and cost-utility analyses (CUA) have become popular types of economic evaluations (EE) used for evidence-based decision-making in healthcare resource allocation. Newborn screening programs (NBS) can have significant clinical benefits for society, and cost-effectiveness analysis may help to select the optimal strategy among different screening programs, including the no-screening option, on different conditions. These economic analyses of NBS, however, are hindered by several methodological challenges. This study explored the methodological quality in recent NBS economic evaluations and analyzed the main challenges and strategies adopted by researchers to deal with them.

METHODS

A scoping review was conducted according to PRISMA methodology to identify CEAs and CUAs of NBS. The methodological quality of the retrieved studies was assessed quantitatively using a specific guideline for the quality assessment of NBS economic evaluations, by calculating a general score for each EE. Challenges in the studies were then explored using thematic analysis as a qualitative synthesis approach.

RESULTS

Thirty-five studies met the inclusion criteria. The quantitative analysis showed that the methodological quality of NBS economic evaluations was heterogeneous. Lack of clear description of items related to results, discussion, and discounting were the most frequent flaws. Methodological challenges in performing EEs of neonatal screenings include the adoption of a long time horizon, the use of quality-adjusted life years as health outcome measure, and the assessment of costs beyond the screening interventions.

CONCLUSIONS

The results of this review can support future economic evaluation research, aiding researchers to develop a methodological guidance to perform EEs aimed at producing solid results to inform decisions for resource allocation in neonatal screening.

Review: Why screen for severe combined immunodeficiency disease?

Newborn screening for severe combined immunodeficiency (SCID) is now routinely performed in many countries across Europe and around the world. The number of T-cell receptor excision circles (TRECs) reflects T cell levels. TREC quantification is possible using dried blood spot (DBS) samples already collected from newborns to screen for other conditions. This method is very sensitive and highly specific. Data in the literature show that the survival rate for children with SCID is much higher when the disease is detected through early screening, as opposed to a later diagnosis. Newborns diagnosed with SCID may receive the appropriate care quickly, before the onset of serious infectious complications, which raises survival rates, improves quality of life, and limits side effects and treatment costs. At the request of the French Ministry of Health, France's National Authority for Health (Haute Autorité de Santé) is expected to issue recommendations on this topic soon. The nationwide DEPISTREC study, involving 48 maternity units across France, showed that routine SCID screening is feasible and effective. Such screening offers the additional benefit of also diagnosing non-SCID lymphopenia within the infant population.

Newborn Screening through TREC, TREC/KREC System for Primary Immunodeficiency with limitation of TREC/KREC. Comprehensive Review

INTRODUCTION

Newborn screening (NBS) by quantifying T cell receptor excision circles (TRECs) and Kappa receptor excision circles in neonatal dried blood spots (DBS) enables early diagnosis of different types of primary immune deficiencies. Global newborn screening for PID, using an assay to detect T-cell receptor excision circles (TREC) in dried blood spots (DBS), is now being performed in all states in the United States. In this review, we discuss the development and outcomes of TREC, TREC/KREC combines screening, and continued challenges to implementation.

OBJECTIVE

To review the diagnostic performance of published articles for TREC and TREC/ KREC based NBS for PID and its different types.

METHODS

Different research resources were used to get an approach for the published data of TREС and KREC based NBS for PID like PubMed, Scopus, Google Scholar, Research gate EMBASE. We extracted TREC and KREC screening Publisher with years of publication, content and cut-off values, and a number of retests, repeat DBS, and referrals from the different published pilot, pilot cohort, Case series, and cohort studies.

RESULTS

We included the results of TREC, combined TREC/KREC system based NBS screening from different research articles, and divided these results between the Pilot studies, case series, and cohort. For each of these studies, different parameter data are excluded from different articles. Thirteen studies were included, re-confirming 89 known SCID cases in case series and reporting 53 new SCID cases in 3.15 million newborns. Individual TREC contents in all SCID patients were <25 TRECs/μl (except in those evaluated with the New York State assay).

CONCLUSION

TREC and KREC sensitivity for typical SCID and other types of PID was 100 %. It shows its importance and anticipating the significance of implementation in different undeveloped and developed countries in the NBS program in upcoming years. Data adapting the screening algorithm for pre-term/ill infants reduce the amount of false-positive test results.

Nonsevere combined immunodeficiency T-cell lymphopenia identified through newborn screening

PURPOSE OF REVIEW

Although severe combined immunodeficiency (SCID) is the primary target condition for newborn screening (NBS), over 25 secondary targets, conditions other than SCID, have been identified. There is no standard method for evaluating neonates with non-SCID T-cell lymphopenia (TCL) and no standard approaches to treatment. We will describe these conditions and discuss recommendations for evaluating and follow-up of non-SCID TCL detected by NBS.

RECENT FINDINGS

The birth prevalence of non-SCID TCL detected through SCID NBS is higher than SCID and can be a burden on NBS programs. We will present some publications discussing outcomes and comorbidities in these patients.

SUMMARY

NBS for SCID has been very successful in identifying infants with SCID at birth to institute early life saving therapies. TCL due to other conditions can cause significant immune deficiency and treatment is dependent on the cause of the defect, as well as the magnitude of the immunodeficiency. Data collection from NBS programs should include assessment of various therapies and clinical outcomes. Better systems for recording long-term outcomes of SCID NBS including both SCID and non-SCID conditions should become a priority for NBS programs. This will help to advance the goal of NBS programs: improve outcomes in the most cost-effective manner.

Expanding TREC and KREC Utility in Primary Immunodeficiency Diseases Diagnosis

Primary immunodeficiency diseases (PID) area heterogeneous group of disorders caused by genetic defects of the immune system, which manifest clinically as recurrent infections, autoimmune diseases or malignancies. Early detection of PID remains a challenge, particularly in older children with milder and less specific symptoms. This study aimed to assess TREC and KREC diagnostic ability in PID. Data from children assessed by clinical immunologists at Speransky Children's Hospital, Moscow, Russia with suspected immunodeficiencies were analyzed between May 2013 and August 2016. Peripheral blood samples were sent for TREC/KREC, flow cytometry (CD3, CD4, CD8 and CD19), IgA and IgG analysis. A total of 434 children [189 healthy, 97 with group I and II PID (combined T and B cell immunodeficiencies & well-defined syndromes with immunodeficiency) and 148 group III PID (predominantly antibody deficiencies)] were included. Area under the curve (AUC) for TREC in PID groups I and II diagnosis reached 0.82 (CI = 0.75-0.90), with best model providing sensitivity of 65% and specificity of 92%. Neither TREC, nor KREC had added value in PID group III diagnosis. In this study, the predictive value of TREC and KREC in PID diagnosis was examined. We found that the TREC had some diagnostic utility for groups I and II PID. Possibly, addition of TREC measurements to existing clinical diagnostic algorithms may improve their predictive value. Further investigations on a larger cohort are needed to evaluate TREC/KREC abilities to be used as diagnostic tools on a wider scale.

Cost and impact of early diagnosis in primary immunodeficiency disease: A literature review

BACKGROUND

New, innovative, costly diagnostic methods for patients with primary immunodeficiencies (PID) demand upfront insight into their potential cost savings and added value for individual patients. As such, high quality, comparable economic evaluations are of utmost importance to enable informed decisions. The objective of this review was therefore to create an extensive overview of current costing studies and potential cost savings of early diagnosis in primary immunodeficiency disease.

METHODS

A literature search in PubMed was conducted and studies involving any form of costing study in the field of PIDs were included. Of the included studies, study characteristics, cost parameters and benefits of early diagnosis were extracted and outlined in separate tables.

RESULTS

Twenty two studies met the inclusion criteria and were included in the review. The papers were categorized according to their subject: neonatal screening for severe combined immunodeficiency (SCID), Ig replacement therapies and studies reporting on costs of general or specific PIDs. Within and between these groups variability in reported costing characteristics was observed. In studies that reported cost savings pre- and post-diagnosis, cost savings ranged from 6500 to 108,463 USD of total costs per patient.

CONCLUSION

This literature review shows that, regardless of what aspect of PIDs has been studied, in nearly all cases early diagnosis reduces health care consumption and leads to better health outcomes for patients with PIDs. We found considerable variability in costing characteristics of economic evaluations of PID patients, which hampers the comparability of outcomes. More effort is needed to create uniformity and define cost parameters in economic evaluations in the field of PIDs, facilitating further prospective research to extensively assess the benefits of early diagnosis.

First Universal Newborn Screening Program for Severe Combined Immunodeficiency in Europe. Two-Years' Experience in Catalonia (Spain)

Severe combined immunodeficiency (SCID), the most severe form of T-cell immunodeficiency, can be screened at birth by quantifying T-cell receptor excision circles (TRECs) in dried blood spot (DBS) samples. Early detection of this condition speeds up the establishment of appropriate treatment and increases the patient's life expectancy. Newborn screening for SCID started in January 2017 in Catalonia, the first Spanish and European region to universally include this testing. The results obtained in the first 2 years of experience are evaluated here. All babies born between January 2017 and December 2018 were screened. TREC quantification in DBS (1.5 mm diameter) was performed with the Enlite Neonatal TREC kit from PerkinElmer (Turku, Finland). In 2018, the retest cutoff in the detection algorithm was updated based on the experience gained in the first year, and changed from 34 to 24 copies/μL. This decreased the retest rate from 3.34 to 1.4% (global retest rate, 2.4%), with a requested second sample rate of 0.23% and a positive detection rate of 0.02%. Lymphocyte phenotype (T, B, NK populations), expression of CD45RA/RO isoforms, percentage and intensity of TCR αβ and TCR γδ, presence of HLA-DR+ T lymphocytes, and in vitro lymphocyte proliferation were studied in all patients by flow cytometry. Of 130,903 newborns screened, 30 tested positive, 15 of which were male. During the study period, one patient was diagnosed with SCID: incidence, 1 in 130,903 births in Catalonia. Thirteen patients had clinically significant T-cell lymphopenia (non-SCID) with an incidence of 1 in 10,069 newborns (43% of positive detections). Nine patients were considered false-positive cases because of an initially normal lymphocyte count with normalization of TRECs between 3 and 6 months of life, four infants had transient lymphopenia due to an initially low lymphocyte count with recovery in the following months, and three patients are still under study. The results obtained provide further evidence of the benefits of including this disease in newborn screening programs. Longer follow-up is needed to define the exact incidence of SCID in Catalonia.

What to Do with an Abnormal Newborn Screen for Severe Combined Immune Deficiency

Newborn screening for severe combined immunodeficiency has been implemented in all 50 states. This screening identifies newborns with T-cell lymphopenia. After an abnormal screening, additional testing is needed to determine if the child has severe combined immunodeficiency. Because screening programs vary, it is imperative for the clinical immunologist to understand how screening is done in their state and to prepare an effective assessment protocol for the management of these patients. Part of this assessment should include training and helping to ensure the effective delivery of this news to the family, a skill neither intuitive nor classically taught to immunologists.

Molecular Diagnosis of Inherited Immune Disorders

Primary immunodeficiency diseases are a heterogeneous group of rare inherited disorders of innate or adaptive immune system function. Patients with primary immunodeficiencies typically present with recurrent and severe infections in infancy or young adulthood. More recently, the co-occurrence of autoimmune, benign lymphoproliferative, atopic, and malignant complications has been described. The diagnosis of a primary immunodeficiency disorder requires a thorough assessment of a patient's underlying immune system function. Historically, this has been accomplished at the time of symptomatic presentation by measuring immunoglobulins, complement components, protective antibody titers, or immune cell counts in the peripheral blood. Although these data can be used to critically assess the degree of immune dysregulation in the patient, this approach fall short in at least 2 regards. First, this assessment often occurs after the patient has suffered life-threatening infectious or autoinflammatory complications. Second, these data fail to uncover an underlying molecular cause of the patient's primary immune dysfunction, prohibiting the use of molecularly targeted therapeutic interventions. Within the last decade, the field of primary immunodeficiency diagnostics has been revolutionized by 2 major molecular advancements: (1) the onset of newborn screening in 2008, and (2) the onset of next-generation sequencing in 2010. In this article, the techniques of newborn screening and next-generation sequencing are reviewed and their respective impacts on the field of primary immunodeficiency disorders are discussed with a specific emphasis on severe combined immune deficiency and common variable immune deficiency.

A Cost-Effectiveness Analysis of Newborn Screening for Severe Combined Immunodeficiency in the UK

Severe combined immunodeficiency (SCID) can be detected through newborn bloodspot screening. In the UK, the National Screening Committee (NSC) requires screening programmes to be cost-effective at standard UK thresholds. To assess the cost-effectiveness of SCID screening for the NSC, a decision-tree model with lifetable estimates of outcomes was built. Model structure and parameterisation were informed by systematic review and expert clinical judgment. A public service perspective was used and lifetime costs and quality-adjusted life years (QALYs) were discounted at 3.5%. Probabilistic, one-way sensitivity analyses and an exploratory disbenefit analysis for the identification of non-SCID patients were conducted. Screening for SCID was estimated to result in an incremental cost-effectiveness ratio (ICER) of £18,222 with a reduction in SCID mortality from 8.1 (5-12) to 1.7 (0.6-4.0) cases per year of screening. Results were sensitive to a number of parameters, including the cost of the screening test, the incidence of SCID and the disbenefit to the healthy at birth and false-positive cases. Screening for SCID is likely to be cost-effective at £20,000 per QALY, key uncertainties relate to the impact on false positives and the impact on the identification of children with non-SCID T Cell lymphopenia.

Cost-effectiveness of newborn screening for severe combined immunodeficiency

Severe combined immunodeficiency (SCID) is a condition that often results in severe infections and death at young age. Early detection shortly after birth, followed by treatment before infections occur, largely increases the chances of survival. As the incidence of SCID is low, assessing cost-effectiveness of adding screening for SCID to the newborn screening program is relevant for decision making. Lifetime costs and effects of newborn screening for SCID were compared to a situation without screening in the Netherlands in a decision analysis model. Model parameters were based on literature and expert opinions. Sensitivity analyses were performed. Due to earlier detection, the number of deaths due to SCID per 100,000 children was assessed to decrease from 0.57 to 0.23 and a number of 11.7 quality adjusted life-years (QALYs) gained was expected. Total yearly healthcare costs, including costs of screening, diagnostics, and treatment, were €390,800 higher in a situation with screening compared to a situation without screening, resulting in a cost-utility ratio of €33,400 per QALY gained.Conclusion: Newborn screening for SCID might be cost-effective. However, there is still a lot of uncertainty around the cost-effectiveness estimate. Pilot screening projects are warranted to obtain more accurate estimates for the European situation. What is Known: • Severe combined immunodeficiency (SCID) is a condition that often results in severe infections and death at a young age. • As the incidence of SCID is low, assessing cost-effectiveness of adding screening for SCID to the newborn screening program is needed. What is New: • Newborn screening for SCID is expected to reduce mortality from 0.57 to 0.23 per 100,000 children at additional healthcare costs of €390,800. The cost-utility ratio is €33,400 per QALY gained. • Due to large uncertainty around cost-effectiveness estimates, pilot screening projects are warranted for Europe.

Clinical and economic aspects of newborn screening for severe combined immunodeficiency: DEPISTREC study results

PURPOSE

Severe combined immunodeficiency (SCID) refers to a group of genetic disorders characterized by greatly compromised cellular and humoral immunity. Children with SCID are asymptomatic at birth, but they die from infections within the first months of life if not treated. Quantification of T-cell receptor excision circles is an extremely sensitive screening method for detecting newborns who may have SCID.The goal of the DEPISTREC study was to evaluate the feasibility of nationwide newborn screening for severe T-cell lymphopenia in France as well as its economic and clinical utility.

METHODS

The test universally used for neonatal screening for SCID was the quantification of TRECs on Guthrie cards. We compared a group of 190,517 babies from 48 maternities across the country who underwent newborn SCID screening with a control group of 1.4 million babies out of whom 28 were diagnosed with SCID without such screening during the course of the study.

RESULTS

Within the screening group, 62 babies were found to be lymphopenic, including three with SCID. The cost of screening ranged from 4.7€ to €8.15 per newborn. The average 18-month cost was €257,574 vs €204,697 in the control group.

CONCLUSIONS

In this large-scale study, we demonstrate that routine SCID screening is feasible and effective. This screening offers the additional benefit of aiding in the diagnosis of non-SCID lymphopenia. Economic evaluation allowed us to calculate the cost per test. Newborn screening may also prevent death by SCID before any curative treatment can be administered. The difference in cost between screened and control children could not be ascertained because of the very low numbers and death of one of the children tested.

Introducing Newborn Screening for Severe Combined Immunodeficiency (SCID) in the Dutch Neonatal Screening Program

The implementation of newborn screening for severe combined immunodeficiency (SCID) in the Netherlands is a multifaceted process in which several parties are involved. The Dutch Ministry of Health adopted the advice of the Dutch Health Council to include SCID in the Dutch newborn screening program in 2015. As newborn screening for SCID is executed with a new, relatively expensive assay for the Dutch screening laboratory, an implementation pilot study is deemed instrumental for successful implementation. A feasibility study was performed in which the practicalities and preconditions of expanding the newborn screening program were defined. Cost-effectiveness analysis (CEA) indicated that SCID screening in the Netherlands might be cost-effective, recognizing that there are still many uncertainties in the variables underlying the CEA. Data and experience of the pilot study should provide better estimates of these parameters, thus enabling the actualization of CEA results. Prior to the implementation pilot study, a comparison study of two commercially available SCID screening assays was performed. A prospective implementation pilot study or so-called SONNET study (SCID screening research in the Netherlands with TRECs) started in April 2018 and allows the screening for SCID of all newborns in three provinces of the Netherlands for one year. Based on the results of the SONNET study, the Dutch Ministry of Health will make a final decision about national implementation of newborn screening for SCID in the Netherlands.

Newborn Screening for Severe Combined Immunodeficiency

PURPOSE OF REVIEW

This review provides a brief history of newborn screening (NBS) for severe combined immunodeficiency (SCID), discusses the theoretical basis for the T cell receptor excision circle (TREC) assay, highlights the results of recent studies using the TREC, and provides practical advice for the evaluation of infants with an abnormal TREC assay.

RECENT FINDINGS

Currently, all but three states perform NBS for SCID in the USA. NBS using the TREC assay is highly sensitive in identifying infants with SCID and may also identify infants with T cell lymphopenia due to other causes such as congenital syndromes, multiple congenital anamolies, and some combined immunodeficiencies. Regardless of the genetic etiology, all forms of SCID are characterized by a severe deficiency of naïve T cells. TRECs are a biomarker of newly formed, naïve T cells that have recently left the thymus. Consequently, the TREC assay identifies infants with SCID and other causes of severe T cell lymphopenia.

Using Decision Analysis to Support Newborn Screening Policy Decisions: A Case Study for Pompe Disease

Background: Newborn screening is a public health program to identify conditions associated with significant morbidity or mortality that benefit from early intervention. Policy decisions about which conditions to include in newborn screening are complex because data regarding epidemiology and outcomes of early identification are often incomplete. Objectives: To describe expected outcomes of Pompe disease newborn screening and how a decision analysis informed recommendations by a federal advisory committee. Methods: We developed a decision tree to compare Pompe disease newborn screening with clinical identification of Pompe disease in the absence of screening. Cases of Pompe disease were classified into three types: classic infantile-onset disease with cardiomyopathy, nonclassic infantile-onset disease, and late-onset disease. Screening results and 36-month health outcomes were projected for classic and nonclassic infantile-onset cases. Input parameters were based on published and unpublished data supplemented by expert opinion. Results: We estimated that screening 4 million babies born each year in the United States would detect 40 cases (range: 13–56) of infantile-onset Pompe disease compared with 36 cases (range: 13–56) detected clinically without screening. Newborn screening would also identify 94 cases of late-onset Pompe disease that might not become symptomatic for decades. By 36 months, newborn screening would avert 13 deaths (range: 8–19) and decrease the number of individuals requiring mechanical ventilation by 26 (range: 20–28). Conclusions: Pompe disease is a rare condition, but early identification can improve health outcomes. Decision analytic modeling provided a quantitative data synthesis that informed the recommendation of Pompe disease newborn screening.

Newborn Screening: History, Current Status, and Future Directions

Newborn screening programs aim to achieve presymptomatic diagnosis of treatable disorders allowing for early initiation of medical care to prevent or reduce significant morbidity and mortality. Many of the conditions included in the newborn screening panels are inborn errors of metabolism; however, screening for endocrine, hematologic, immunologic, and cardiovascular diseases, and hearing loss is also included in many panels. Newborn screening tests are not diagnostic and therefore diagnostic testing is needed to confirm or exclude the suspected diagnosis. Further advancement in technology is expected to allow continuous expansion of newborn screening.

Haematopoietic stem cell transplantation for primary immunodeficiency syndromes: A 5-year single-centre experience

AIM

Haematopoietic stem cell transplantation (HSCT) is a central therapy in the treatment of primary immunodeficiency diseases (PIDs). Over the past 5 years, outcomes have been greatly improved due to earlier diagnosis, improved donor availability, advancements in graft manipulation and the use of less toxic preparative regimens. We present a 5-year audit of HSCT for PID at a single Australian tertiary hospital.

METHODS

Retrospective case note review identified diagnosis, pre-transplant medical morbidity, transplant protocol, engraftment, adverse events, post-transplant immune reconstitution and general health.

RESULTS

A total of 22 patients with PID underwent 24 HSCTs at our institution between 2012 and 2016. The most common indications were severe combined immunodeficiency, chronic granulomatous disease and familial haemophagocytic lymphohistiocytosis, with a genetic diagnosis in all but two patients. Reduced intensity or reduced toxicity conditioning was used in 91% of cases, and 75% of the donors were unrelated. Transplant-related mortality at day +100 was 9.5%, and cumulative overall survival was 86%. There were three mortalities, all secondary to viral infection, one of which occurred in the context of graft failure. Two patients remained on immune support, with the remainder achieving adequate immune reconstitution.

CONCLUSIONS

The outcomes for HSCT for PIDs performed at Sydney Children's Hospital were in line with the world's best practice. HSCT should be considered a potential therapeutic option for all Australian PID patients with a valid disease indication.

The Use of Economic Evaluation to Inform Newborn Screening Policy Decisions: The Washington State Experience

POLICY POINTS

Newborn screening not only saves lives but can also yield net societal economic benefit, in addition to benefits such as improved quality of life to affected individuals and families. Calculations of net economic benefit from newborn screening include the monetary equivalent of avoided deaths and reductions in costs of care for complications associated with late-diagnosed individuals minus the additional costs of screening, diagnosis, and treatment associated with prompt diagnosis. Since 2001 the Washington State Department of Health has successfully implemented an approach to conducting evidence-based economic evaluations of disorders proposed for addition to the state-mandated newborn screening panel.

CONTEXT

Economic evaluations can inform policy decisions on the expansion of newborn screening panels. This article documents the use of cost-benefit models in Washington State as part of the rule-making process that resulted in the implementation of screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency and 4 other metabolic disorders in 2004, cystic fibrosis (CF) in 2006, 15 other metabolic disorders in 2008, and severe combined immune deficiency (SCID) in 2014.

METHODS

We reviewed Washington State Department of Health internal reports and spreadsheet models of expected net societal benefit of adding disorders to the state newborn screening panel. We summarize the assumptions and findings for 2 models (MCAD and CF) and discuss them in relation to findings in the peer-reviewed literature.

FINDINGS

The MCAD model projected a benefit-cost ratio of 3.4 to 1 based on assumptions of a 20.0 percentage point reduction in infant mortality and a 13.9 percentage point reduction in serious developmental disability. The CF model projected a benefit-cost ratio of 4.0-5.4 to 1 for a discount rate of 3%-4% and a plausible range of 1-2 percentage point reductions in deaths up to age 10 years.

CONCLUSIONS

The Washington State cost-benefit models of newborn screening were broadly consistent with peer-reviewed literature, and their findings of net benefit appear to be robust to uncertainty in parameters. Public health newborn screening programs can develop their own capacity to project expected costs and benefits of expansion of newborn screening panels, although it would be most efficient if this capacity were shared among programs.

Cost and Cost-Effectiveness Assessments of Newborn Screening for Critical Congenital Heart Disease Using Pulse Oximetry: A Review

Screening newborns for critical congenital heart disease (CCHD) using pulse oximetry is recommended to allow for the prompt diagnosis and prevention of life-threatening crises. The present review summarizes and critiques six previously published estimates of the costs or cost-effectiveness of CCHD screening from the United Kingdom, United States, and China. Several elements that affect CCHD screening costs were assessed in varying numbers of studies, including screening staff time, instrumentation, and consumables, as well as costs of diagnosis and treatment. A previous US study that used conservative assumptions suggested that CCHD screening is likely to be considered cost-effective from the healthcare sector perspective. Newly available estimates of avoided infant CCHD deaths in several US states that implemented mandatory CCHD screening policies during 2011-2013 suggest a substantially larger reduction in deaths than was projected in the previous US cost-effectiveness analysis. Taking into account these new estimates, we estimate that cost per life-year gained could be as low as USD 12,000. However, that estimate does not take into account future costs of health care and education for surviving children with CCHD nor the costs incurred by health departments to support and monitor CCHD screening policies and programs.

Newborn screening: a review of history, recent advancements, and future perspectives in the era of next generation sequencing

PURPOSE OF REVIEW

The purpose of this review is to summarize the development and recent advancements of newborn screening.

RECENT FINDINGS

Early initiation of medical care has modified the outcome for many disorders that were previously associated with high morbidity (such as cystic fibrosis, primary immune deficiencies, and inborn errors of metabolism) or with significant neurodevelopmental disabilities (such as phenylketonuria and congenital hypothyroidism). The new era of mass spectrometry and next generation sequencing enables the expansion of the newborn screen panel, and will help to address technical issues such as turnaround time, and decreasing false-positive and false-negative rates for the testing.

SUMMARY

The newborn screening program is a successful public health initiative that facilitates early diagnosis of treatable disorders to reduce long-term morbidity and mortality.