Implementation of nationwide screening of pregnant women for HTLV-1 infection in Japan: analysis of a repeated cross-sectional study

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.

Measures for the Prevention of Mother-to-Child Human T-Cell Leukemia Virus Type 1 Transmission in Japan: The Burdens of HTLV-1-Infected Mothers

The main mode of mother-to-child transmission of the human T-cell leukemia virus (HTLV)-1 is through breastfeeding. Although the most reliable nutritional regimen to prevent HTLV-1 transmission is exclusive formula feeding, a recent meta-analysis revealed that short-term breastfeeding within 90 days does not increase the risk of infection. The protocol of the Japanese Health, Labor, and Welfare Science Research Group primarily recommended exclusive formula feeding for mothers who are positive for HTLV-1. However, there has been no quantitative research on the difficulties experienced by HTLV-1-positive mothers in carrying out these nutritional regimens, including the psychological burden. Therefore, this review was performed to clarify the burdens and difficulties encountered by mothers who are positive for HTLV-1; to this end, we analyzed the data registrants on the HTLV-1 career registration website "Carri-net" website. The data strongly suggest that it is not sufficient to simply recommend exclusive formula feeding or short-term breastfeeding as a means of preventing mother-to-child transmission; it is important for health care providers to understand that these nutritional regimens represent a major burden for pregnant women who are positive for HTLV-1 and to provide close support to ensure these women's health.

Cost-effectiveness of human T-cell leukemia virus type 1 (HTLV-1) antenatal screening for prevention of mother-to-child transmission

BACKGROUND

Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia-lymphoma (ATL) and HTLV-1-associated myelopathy-tropical spastic paraparesis (HAM/TSP) with a poor prognosis. This study aimed to evaluate the cost-effectiveness and health impact of HTLV-1 antenatal screening.

METHODOLOGY/PRINCIPAL FINDINGS

A state-transition model was developed for HTLV-1 antenatal screening and no screening over a lifetime horizon from a healthcare payer perspective. A hypothetical cohort of 30-year-old individuals was targeted. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios (ICERs), HTLV-1 carriers, ATL cases, HAM/TSP cases, ATL-associated deaths, and HAM/TSP-associated deaths. The willingness-to-pay (WTP) threshold was set at US$50,000 per QALY gained. In the base-case analysis, HTLV-1 antenatal screening (US$76.85, 24.94766 QALYs, 24.94813 LYs, ICER; US$40,100 per QALY gained) was cost-effective compared with no screening (US$2.18, 24.94580 QALYs, 24.94807 LYs). Cost-effectiveness was sensitive to the maternal HTLV-1 seropositivity rate, HTLV-1 transmission rate with long-term breastfeeding from HTLV-1 seropositive mothers to children, and the cost of the HTLV-1 antibody test. HTLV-1 antenatal screening was cost-effective when the maternal HTLV-1 seropositivity rate was greater than 0.0022 and the cost of the HTLV-1 antibody test was lower than US$94.8. Probabilistic sensitivity analysis using a second-order Monte-Carlo simulation showed that HTLV-1 antenatal screening was 81.1% cost-effective at a WTP threshold of US$50,000 per QALY gained. For 10,517,942 individuals born between 2011 and 2021, HTLV-1 antenatal screening costs US$785 million, increases19,586 QALYs and 631 LYs, and prevents 125,421 HTLV-1 carriers, 4,405 ATL cases, 3,035 ATL-associated deaths, 67 HAM/TSP cases, and 60 HAM/TSP-associated deaths, compared with no screening over a lifetime.

CONCLUSION/SIGNIFICANCE

HTLV-1 antenatal screening is cost-effective and has the potential to reduce ATL and HAM/TSP morbidity and mortality in Japan. The findings strongly support the recommendation for HTLV-1 antenatal screening as a national infection control policy in HTLV-1 high-prevalence countries.

Mother-to-Child Transmission of Human T-Cell Leukemia Virus Type 1: Mechanisms and Nutritional Strategies for Prevention

Approximately 95% of mother-to-child transmission (MTCT) of human T-cell leukemia virus type-1 (HTLV-1) is derived from prolonged breastfeeding, which is a major cause of adult T-cell leukemia (ATL). Exclusive formula feeding (ExFF) is therefore generally used to prevent MTCT. A recent cohort study revealed that 55% of pregnant carriers chose short-term breastfeeding for ≤3 months in Japan. Our meta-analysis showed that there was no significant increase in the risk of MTCT when breastfeeding was carried out for ≤3 months compared with ExFF (pooled relative risk (RR), 0.72; 95% confidence interval (CI), 0.30-1.77), but there was an almost threefold increase in risk when breastfeeding was carried out for up to 6 months (pooled RR, 2.91; 95% CI, 1.69-5.03). Thus, short-term breastfeeding for ≤3 months may be useful in preventing MTCT. Breastmilk is the best nutritional source for infants, and any approach to minimizing MTCT by avoiding or limiting breastfeeding must be balanced against the impact on the child's health and mother-child bonding. To minimize the need for nutritional interventions, it is necessary to identify factors that predispose children born to carrier mothers to MTCT and thereby predict MTCT development with a high degree of accuracy.

Pregnancy complicated by HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP): a case report

Pregnancy was not associated with deterioration of HAM nor was HAM associated with adverse pregnancy outcome in this case. These findings suggest that women with HAM/TSP, even those who use a wheelchair, should not be discouraged from pregnancy.

Implications of human T-lymphotropic virus in pregnancy: A case report and a review of the diagnostic criteria and management proposal

Human T-lymphotropic virus (HTLV) is considered to be the most highly oncogenic existing virus, being the cause of several fatal diseases such as adult T cell leukemia-lymphoma (ATL) and HTLV-I-associated myelopathy (HAM). The main transmission methods are unprotected sexual intercourse, vertical transmission and breastfeeding and direct exposure to infected blood or tissue. The identification of infected mothers prior to delivery is a highly important step in preventing mother to child transmission. Universal antenatal screening for HTLV is not recommended in Romania, although there are sufficient data demonstrating the risk of vertical transmission. We present the case of an HTLV-1-infected pregnant woman, with an aim to highlight: i) points of strategy for the management of HTLV during pregnancy; ii) the particularities of the course of pregnancy; and iii) the aspects that show the importance of knowing the status regarding the HTLV infection antepartum. The case was particular due to the ascendant proviral load during the pregnancy period, which led to the initiation of antiretroviral therapy and the particular pregnancy outcome with preterm rupture of membranes and fetal growth restriction. According to current recommendations, pregnant women infected with HTLV-1 should be advised to refrain from donating blood, body organs, or other tissues. There is no evidence of the number of individuals infected with this virus in Romania at present, and the diagnosis can only occur by chance. A specific treatment or immunization for HTLV infection does not currently exist, thus preventive methods are the only tool to reduce the prevalence and mortality of this infection.