Human T Cell Lymphotropic Virus Type 1 Global Prevalence Associated with the Human Development Index: Systematic Review with Meta-Analysis

Impact and economic analysis of human T-cell lymphotropic virus type 1 (HTLV-1)-targeted antenatal screening, England and Wales, 2021

BackgroundHuman T-cell lymphotropic virus type 1 (HTLV-1) is a neglected virus that can cause severe disease and be transmitted from mother to child through breastfeeding. Avoidance of breastfeeding prevents 80% of vertical transmission. The United Kingdom (UK) is currently assessing whether HTLV-1-targeted antenatal screening should be implemented.AimWe aimed to assess the impact and cost-effectiveness of a targeted programme to prevent HTLV-1 vertical transmission in England and Wales.MethodsWe estimated the number of pregnant women who have high risk of HTLV-1 infection based on their or their partner's country of birth. With data from 2021, we used a mathematical model to assess cost-effectiveness of HTLV-1 antenatal screening. We also estimated the annual number of infant infections and the number that could be prevented with screening and intervention.ResultsWe estimate that ca 99,000 pregnant women in England and Wales have high risk of HTLV-1 infection. In the absence of screening, 74 (range: 25-211) HTLV-1 infections in infants would be expected to occur every year in England and Wales. Implementation of targeted screening would prevent 58 (range: 19-164) infant infections annually. The intervention is effective (incremental 0.00333 quality-adjusted life years (QALY)) and cost-saving (GBP -57.56 (EUR -66.85)).ConclusionOur findings support implementation of HTLV-1 targeted antenatal screening to reduce vertical transmission from mothers to infants in the UK.

Screening for HTLV-1 infection should be expanded in Europe

Human T-cell lymphotropic virus type 1 (HTLV-1) infection is spreading globally at an uncertain speed. Sexual, mother-to-child, and parenteral exposure are the major transmission routes. Neither vaccines nor antivirals have been developed to confront HTLV-1, despite infecting over 10 million people globally and causing life-threatening illnesses in 10% of carriers. It is time to place this long-neglected disease firmly into the 2030 elimination agenda. Current evidence supports once-in-life testing for HTLV-1, as recommended for HIV, hepatitis B and C, along with targeted screening of pregnant women, blood donors, and people who attended clinics for sexually transmitted infections (STIs). Similar targeted screening strategies are already being performed for Chagas disease in some Western countries in persons from Latin America. Given the high risk of rapid-onset HTLV-1-associated myelopathy, universal screening of solid organ donors is warranted. To minimize organ wastage, however, the specificity of HTLV screening tests must be improved. HTLV screening of organ donors in Europe has become mandatory in Spain and the United Kingdom. The advent of HTLV point-of-care kits would facilitate testing. Finally, increasing awareness of HTLV-1 will help those living with HTLV-1 to be tested, clinically monitored, and informed about transmission-preventive measures.

Human T-lymphotropic virus-1 infection among Latin American pregnant women living in Spain

Objectives

Human T-lymphotropic virus (HTLV) antenatal screening is not mandatory in Spain. Surveys conducted decades ago reported HTLV-1 seroprevalence rates of 0.2% among foreign pregnant women in Spain. The migrant flow to Spain from HTLV-1 endemic regions in Latin America and sub-Saharan Africa has increased during the last decade. Currently, 25% of pregnant women in Spain are foreigners.

Methods

From January 2021 to October 2023 a cross-sectional study was carried out in all consecutive pregnant women attended at eleven Spanish clinics. A commercial enzyme immunoassay (EIA) was used for screening of serum HTLV-1/2 antibodies. Reactive samples were confirmed by immunoblot.

Results

A total of 9813 pregnant women with a median age of 34 years-old were examined. Native Spaniards were 6977 (76.5%). Of 2147 foreigners (23.5%), 903566 (9.9%) were Latin Americans, 416 (4.5%) North Africans, 293 (3.2%) from Romania, and 196 (2.1%) from sub-Saharan Africa. A total of 47 samples were EIA reactive but only five were confirmed as HTLV-1 positive using immunoblot. Infected women came from Paraguay, Colombia, the Dominican Republic, Venezuela and Peru. All but one were primigravida, with ages ranging from 20 to 33 years-old. One was HIV-1 positive, and another was infected with Chlamydia trachomatis.

Conclusion

The overall seroprevalence for HTLV-1 among pregnant women in Spain is 0.05% but rises ten-fold (0.55%) among Latin Americans. This rate is higher than in surveys conducted decades ago. Our results support that anti-HTLV testing should be part of antenatal screening in Spain in pregnant women coming from Latin America, as it is already done with Chagas disease.

How do socioeconomic determinants of health affect the likelihood of living with HTLV-1 globally? A systematic review with meta-analysis

Introduction

Human T Lymphotropic Virus type 1 (HTLV-1) is a neglected retrovirus associated with many clinical disorders, most notably Adult T-cell Leukemia/Lymphoma and HTLV-1-Associated Myelopathy (HAM). Found in endemic clusters across the world, high prevalence has been reported in minoritized groups who suffer from health inequities. This study investigates the association between HTLV-1 prevalence and the following socioeconomic determinants of health: education, income, and employment, which are markers of health inequity.

Methods

A systematic review was conducted by searching the following databases: Ovid/Medline, Embase, Global Health Database, Web of Science, LILACS and SciELO. Primary studies in English, Spanish and Portuguese mentioning HTLV-1 and one of education, income and/or employment were included. A random-effects meta-analysis was performed, and odds ratios (OR) were calculated to determine the association between these socioeconomic determinants of health and HTLV-1 prevalence.

Results

42 studies were included. The likelihood of having HTLV-1 was higher in individuals with less than completed primary education compared to those who completed primary education (OR 1.86 [95% CI 1.34-2.57]; p < 0.01). This may be because individuals with low education have reduced access to and understanding of health information, thus increasing the prevalence of risk factors associated with HTLV-1 infection. No other determinants were found to be statistically significant.

Conclusion

Fewer years of schooling are associated with increased likelihood of contracting HTLV-1. Therefore, health promotion materials and public health policies regarding HTLV-1 must consider those with lower educational levels to effectively reduce disease transmission.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=335004, identifier (CRD42022335004).

HTLV infection in persons with sexually transmitted diseases in Spain

Background

HTLV-1 infection is a neglected disease, despite estimates of 10 million people infected worldwide and producing life-threatening illnesses in 10% of carriers. Sexual transmission is the main route of contagion. However, HTLV-1 is not listed among sexually transmitted infections (STIs).

Methods

Serum from all consecutive individuals who had attended six STI clinics across Spain during the last 12 months were tested for HTLV antibodies using a commercial enzyme immunoassay (EIA). Reactive samples were confirmed by immunoblot.

Results

A total of 2,524 samples were examined. The majority (1,936; 76.7%) belonged to men, of whom 676 (34.9%) were men who have sex with men (MSM) receiving HIV pre-exposure prophylaxis. Although native Spaniards predominated (1,470; 58.2%), up to 593 (23.5%) came from Latin America and 139 (5.5%) were African. A total of 26 individuals were initially EIA reactive and immunoblot confirmed 5 as HTLV-1 and 7 as HTLV-2. All but one HTLV-1+ case came from Latin America. Three were men and two were women. Among Latin Americans, the HTLV-1 seroprevalence was 0.67%. In contrast, all seven HTLV-2+ were native Spaniards and former injection drug users, and all but one were HIV+.

Conclusion

The rate of HTLV infection among individuals with STIs in Spain is 0.5%, which is greater than in the general population. These results support the introduction of universal HTLV screening in persons who attend clinics for STIs.