Decision-analytic model for Human T-lymphotropic virus 1 (HTLV-1) antenatal screening in the UK

Project overview 

This project will examine whether screening only pregnant women who are at higher risk (targeted screening) improves health outcomes and provides good value for money. A mathematical model will be developed comparing targeted antenatal screening with no screening, considering both health outcomes and costs over the lifetimes of mothers and children. A separate review will examine the association between HTLV-1 infection and adverse health outcomes including all-cause mortality, cause-specific mortality linked to defined clinical conditions, cause-specific mortality linked to asymptomatic HTLV-1 infection, and morbidity (in relation to defined clinical conditions).

Status: ongoing

Contact: rob.hodgson@york.ac.uk 

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What is the problem?

HTLV-1 (short for Human T-lymphotropic virus 1) is a virus that infects blood cells which are essential for helping the body fight infection. Although infection with HTLV-1 lasts for a person’s lifetime, many people carry the virus without feeling ill. However, some people develop conditions such as skin or lung problems, including other conditions linked to HTLV-1. A small proportion of people become seriously ill with a rare type of cancer (called adult T-cell leukaemia/lymphoma) or an illness resulting in weakening and stiffness of the muscles in the legs which gets worse as time goes on (known as HTLV-1-associated myelopathy/tropical spastic paraparesis). 

HTLV-1 infection is common in the Caribbean, South America, Romania, Iran, Africa, Japan, Melanesia and Australia. The number of pregnant women with detected HTLV-1 infection in the UK is low (approximately 223 per year) and those affected are likely to be linked to one of the countries mentioned above (for example, they were born there). One way that the virus can be spread is from mother to baby, especially during breastfeeding. To minimise the spread, it may be suggested that mothers avoid breastfeeding altogether or only do it for a short time (less than six months). They may be offered medication which stops the flow of breast milk.

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What are we doing?

There is currently no antenatal screening programme for HTLV-1 in the UK although screening may be offered at specialist healthcare centres for those linked to the countries mentioned above.

We will develop a decision model to assess the clinical and economic impact of a targeted screening programme for pregnant women at high risk of HTLV-1, such as those born in regions where the virus is prevalent. The model will estimate the number of HTLV-1 transmissions that could be prevented and the resulting reduction in associated illnesses. Additionally, we will examine the potential harms of screening, including the psychological effects of diagnosis and the implications of avoiding breastfeeding, which otherwise offers significant benefits for both mothers and infants. Finally, our analysis will evaluate the costs of implementing a targeted screening programme and determine whether it provides good value for money. We will also perform a systematic review of studies assessing the health consequences of being infected with HTLV-1. The review will look at what happens to people who have confirmed HTLV-1 infection compared with those who are confirmed as not having the virus. A range of health consequences will be considered including the number of people who became ill and the number of people who died. Where possible, we will record details of the nature of the illnesses and the cause of death. It is possible that information from the review may help with the economic model and/or discussions with stakeholders.