Comments to the document GEPI-SEIMC screening recommendations for patients with suspected strongyloidosis

Dear Editor:

Recently, the Grupo de Estudio de Patología Importada (GEPI) [Imported Pathology Study Group] of the Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica (SEIMC) [Spanish Society of Infectious Diseases and Clinical Microbiology] published a document on its website entitled "GEPI-SEIMC screening recommendations for patients with suspected strongyloidosis".¹ We applaud the publication of this document, as it is vitally necessary to raise awareness of the need to screen for strongyloidiasis in the immunosuppressed or those at risk of immunosuppression, including people with SARS CoV-2 infection due to receive treatment with corticosteroids and/or other immunosuppressive drugs,^2,3 and to provide recommendations on how to perform such screening based on current scientific evidence. However, we believe a number of points need to be made.

First of all, while we agree that the technique of choice for screening strongyloidiasis is serology, there are studies that show that it presents insufficient sensitivity in immunosuppressed patients,⁴ whereby more evidence is needed to recommend serology as the only screening technique in the immunosuppressed population. In fact, the recommendations of the latest evidence-based guidelines are to combine serology with parasitology methods in patients already immunosuppressed.⁵

Secondly, and with regard to avoiding systematic empirical treatment, there is solid scientific evidence that presumptive empirical treatment is a cost-effective,^6,7 and even cost-saving, practice, particularly in patients who are immunosuppressed or are at risk of immunosuppression, without undermining the health outcomes for the patients.^7,8 We believe that this evidence should be taken into account when establishing recommendations. In addition, in many Spanish centres, including some of those in areas of Spain where strongyloidiasis is endemic,⁹ this serology is not available at the local laboratory and results take an unacceptably long time, considering the ensuing delay in initiating treatment in patients who are to be immunosuppressed. The current recommendations, issued prior to the publication of the cost-effectiveness studies, are to administer empirical treatment in immunosuppressed patients or candidates for immunosuppression if infection cannot be ruled out within an appropriate time.⁵ We therefore believe that waiting for the patient to develop signs and symptoms of hyperinfestation or disseminated strongyloidiasis before starting empirical treatment exposes them to an unnecessary risk. Empirical treatment should be aimed precisely at preventing the development of hyperinfestation syndrome or disseminated infection. Moreover, once the patient presents symptoms consistent with hyperinfection or disseminated infection, the recommendation should not be the use of single-dose ivermectin 200 mcg/kg, as that regimen has only been studied in immunocompetent people without disseminated disease.¹⁰

In view of all the above, we thank the GEPI-SEIMC for publishing these necessary recommendations, and we hope that these points will be taken into account in future versions of the document.