Dear Editor, We read the interesting article of “ the neuroinvasive potential of SARS-CoV2maybe at least partially responsible for the respiratory failure of COVID-19 patients” by Li et al. (1) that mentioned a heavy infection of the brainstem in patients with SARS-COV that could be extended to SARS-COV2 (COVID-19) infection due to the high similarity between them. Furthermore, the authors claimed this invasion was responsible for the acute respiratory syndrome caused by this viral infection. They also mentioned that via in vivo models, intranasal entry of low doses of SARS-COV or MERSCOV may be spread through olfactory nerves to other areas of brains such as brainstems and thalamus (1). As you know, here in Iran, we are also struggling with COVID-19 infection. Nevertheless, like any other regions with limited resources around the world, due to the shortage in laboratory tests, and false-negative results or incompatibility of clinical manifestations and laboratory or imaging findings, we may miss some cases of COVID-19 in our area...

Introduction: Olfactory training is accounted as a significantly beneficial therapy for hyposmia or ANOSMIA. There is some evidence about methylxanthine usage for this issue. In the present study, we have investigated the effects of topical aminophylline in hyposmic and anosmic patients. Materials and Methods: In this clinical trial study, patients were randomly divided into two groups (n= 20/each), the case group was given aminophylline drops over a three-month period (using the contents of the vial aminophylline in the form of nasal drops, 250 micrograms daily) with olfactory training and the control group was given normal saline drops with olfactory training over a three-month period. The olfactory capacities were assessed before the start and after the completion of treatments using a valid and reliable smell identification test. Results: In the saline and aminophylline groups, the mean ±,SD relative changes in SIT score were 0. 55±, 0. 31 and 0. 85±, 0. 56, respectively. As a result, the SIT score in the saline group climbed by 55 percent but increased by 85 percent in the aminophylline group. The difference in SIT score between pre-and posttest was meaningful in both groups (P< 0. 001). The aminophylline group scored significantly higher according to the marginal longitudinal regression model, adjusting baseline parameters. Conclusions: Intranasal aminophylline plus olfactory training significantly improved SIT scores in severe hyposmia or ANOSMIA. Hypothetically, these effects are mediated through changes in cAMP and cGMP.