Pooling of sera for human T-cell lymphotropic virus (HTLV) screening in a time of increasing health care expenditure and limited resources

Seroprevalence of Human T-Cell Lymphotropic Virus-1 in a Jamaican Antenatal Population and Assessment of Pooled Testing as a Cost Reduction Strategy for Implementation of Routine Antenatal Screening

Mother to child transmission (MTCT) of human T-cell lymphotropic virus (HTLV)-1 is associated with increased risk of adult T-cell leukemia and can be unrecognized without routine antenatal screening. We assessed the seroprevalence of HTLV-1/2 among pregnant women attending The University Hospital of the West Indies Antenatal Clinic, 2019, and validated a cost-effective strategy to screen antenatal clinic attendees for HTLV-1/2. Residual antenatal samples from 370 women were tested for HTLV-1/2 by chemiluminescence microparticle immunoassay (CMIA). Six samples were confirmed HTLV-1 positive by Western blot (none for HTLV-2) for a prevalence of 1.62%. Four mother-child pairs were able to be recruited for HTLV testing of children, with two children testing HTLV-1/2 positive. Medical records of HTLV-1-infected women revealed that all women breastfed, indicating an unrecognized risk for HTLV MTCT. To assess whether pooling of samples as a cost-reduction strategy could be introduced, we pooled all antenatal samples received between November and December 2021 into 12 pools of eight samples/pool. Two pools were CMIA positive, and de-pooling of samples identified two CMIA-positive samples (one per pool), both confirmed as HTLV-1 by Western blot. These results indicate that HTLV-1 remains prevalent in pregnant Jamaican women and that sample pooling can be a cost-effective strategy to limit MTCT in Jamaica.

Economic analysis of antenatal screening for human T-cell lymphotropic virus type 1 in Brazil: an open access cost-utility model

BACKGROUND

Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes severe diseases, such as aggressive cancer or progressive neurological disease. HTLV-1 affects mainly people in areas with low human development index and can be transmitted from mother to child, primarily through breastfeeding. Refraining from breastfeeding is an effective intervention to reduce the risk of infection in infants. However, HTLV-1 antenatal screening is not offered globally. According to WHO, the scarcity of cost-effectiveness studies is considered one of the major barriers to the implementation of policies to prevent HTLV-1 infection. Therefore, this study aimed to assess the cost-effectiveness of antenatal screening and postnatal interventions to prevent HTLV-1 mother-to-child transmission in Brazil and to develop an open-access, editable, mathematical model that can be used by other countries and regions to assess different scenarios.

METHODS

In this cost-utility analysis, we constructed a decision tree and a Markov model to assess the cost-effectiveness of HTLV-1 antenatal screening and postnatal interventions (ie, avoidance of breastfeeding, by suppression of lactation with cabergoline, and provision of formula feed) to reduce transmission. For our model, we used data from Brazil and we took the perspective of the public health-care system to estimate costs.

FINDINGS

The implementation of both screening and interventions would result in the prevention of 1039 infections in infants every year in Brazil with an incremental cost-effectiveness ratio (ICER) of US$11 415 per quality-adjusted life-year (QALY). 88% of all probabilistic sensitivity analysis simulations had ICER values lower than the Brazilian cost-effectiveness threshold ($18 107·74 per QALY). HTLV-1 prevalence in pregnant women, the risk of HTLV-1 transmission when breastfeeding lasts for 6 months or more, and the cost of screening tests were the variables with the largest effect on ICER.

INTERPRETATION

HTLV-1 antenatal screening is cost-effective in Brazil. An open-access model was developed, and this tool could be used to assess the cost-effectiveness of such policy globally, favouring the implementation of interventions to prevent HTLV-1 mother-to-child transmission worldwide.

FUNDING

None.

TRANSLATIONS

For the Portuguese and Spanish translations of the abstract see Supplementary Materials section.

Epidemiological and molecular profile of blood donors infected with HTLV-1/2 in the state of Pará, northern Brazil

BACKGROUND

The Human T-lymphotropic virus (HTLV) is a retrovirus of the genus Deltaretrovirus, which belongs to the family Retroviridae. The most important types are HTLV-1 and HTLV-2. It is estimated that between five and 10 million individuals are infected with HTLV-1, worldwide. Studies in the state of Pará indicate that it has the third highest prevalence of HTLV infections of any Brazilian state. The present study describes the epidemiological, serological, and molecular profile of blood donors from the state of Pará that were classified as unfit due to infection by HTLV-1 and 2.

METHODS

The present study is based on a descriptive, retrospective, and cross-sectional review of the epidemiological, serological, and molecular data on blood donations, between January 2015 and December 2019. The data were obtained from the blood bank system and were digitalized to form a database in the Statistical Package for Social Sciences program, version 20. Descriptive statistics were used to determine the absolute and relative frequencies of the qualitative variables. For the quantitative variables, the mean, standard deviation, and minimum and maximum values were calculated. A p < 0.05 significance level was adopted for all analyses.

RESULTS

A total of 632 samples were analyzed, of which 496 (78%) had no detectable proviral DNA and 136 (22%) had detectable HTLV. The HTLV-1 was detected in most (78%; 106/136) of these samples, while only 30 (22%) were detected for HTLV-2. The HTLV proviral DNA was detected primarily in females (69.1%), with a mean age of 40 years, with the highest frequencies of detection being recorded in single individuals (66.2%), first-time donors (74.3%), and individuals that had graduated high school (44.1%). The molecular confirmation of HTLV showed that three-quarters (78%) of the serologically reactive individuals were negative for either types 1 or 2, so the epidemiological profile of these individuals was significantly different from their detectable profile.

CONCLUSIONS

The HTLV is neglected in Brazil; there is thus a clear need for further research in the area of regional hemotherapy and hematology services, in order to contribute to the definition of regional infection profiles, that will be fundamental to the development of effective prophylactic practices for the prevention of the infection and the dissemination of knowledge on the dangers of HTLV in the community.

Laboratory diagnosis of human T-lymphotropic virus in Brazil: assays, flowcharts, challenges, and perspectives

INTRODUCTION

We present a data analysis and review of recent studies regarding the laboratory diagnosis of human T-lymphotropic virus 1 and 2 (HTLV-1/2) infections in Brazil.

METHODS

Target populations, available diagnostic serological assays (screening and complementary tests), molecular assays (in-house), causes of false-positive and false-negative results, and flowcharts were analyzed.

RESULTS

A table presents the target populations, two diagnostic flowcharts (depending on laboratory infrastructure and study population), and recent research that may improve how HTLV-1/2 is diagnosed in Brazil.

CONCLUSIONS

Our results support the implementation of public policies to reduce HTLV-1/2 transmission and its associated diseases.

Specificity of HTLV screening tests and its impact on health care program costs: The perspective of antenatal screening in Brazil

INTRODUCTION:

Brazil ranks first in the number of HTLV-1/-2-infected individuals worldwide. The high morbidity and mortality of HTLV-1-associated diseases, especially following infection in infancy, requires strong action to reduce vertical transmission.

METHODS:

To facilitate the appraisal of the implementation of the HTLV antenatal screening program by the Brazilian Ministry of Health, we determined the costs in distinct scenarios according to HTLV seroprevalence, specificity of the screening test, and type of confirmatory test.

RESULTS:

HTLV antenatal screening would cost R$ 55,777,012-R$ 77,082,123/year. Screening assays with high specificity reduce the need and cost of confirmatory assays by up to 25%.

CONCLUSIONS:

Careful selection of the screening assay is required to optimize the program.