Letter to the editor: Increasing proportion of new HIV diagnoses in Ireland previously diagnosed elsewhere – potential impact on estimating incidence

The use of CD4 counts raises important issues for HIV surveillance and interpretation of findings. The Irish surveillance system, for example, includes all persons newly diagnosed with HIV in Ireland, even if previously diagnosed elsewhere. An increasing proportion of newly-diagnosed HIV cases have previously been diagnosed HIV-positive in another country before arrival in Ireland, and have been receiving antiretroviral therapy (ART). In 2015, 27% (129/485) of newly-diagnosed HIV cases had a previous HIV diagnosis in another country, up from a range of 14%–18% for the years 2011 to 2014 [3]. By risk group, heterosexuals were the group with the highest proportion previously diagnosed HIVpositive (35%, 45/130), followed by men who have sex with men (MSM) (29%, 72/247) and people who inject drugs (PWID) (10%, 5/49). The majority (79%, 102/129) of those with a previous HIV diagnosis, transferred their HIV care to Ireland and 63% (81/129) had been receiving ART before arrival in Ireland.