Dear Editor,

I very much appreciate the interest the observation of post-SARS-CoV‑2 vaccination COVID toes and fingers has gained. R. Mungmumpuntipanip and V. Wiwantikit pointed to the important issue that before making a definitive diagnosis, other causes should be carefully ruled out. I completely agree. Dengue fever is the most frequent arboviral disease encountered in travelers, but global travel restrictions during the COVID-19 pandemic reduced this risk, at least in Europe [1].

The coinfection of patients with SARS-CoV‑2 and Dengue virus is a particular problem in tropical countries and the diseases may show an overlap of cutaneous symptoms. Dengue fever is therefore also an important differential diagnosis in COVID-19 disease [2].

Dengue fever, as suggested by R. Mungmumpuntipanip and V. Wiwantikit, is a common diagnosis in other parts of the, world but not in Saxony, in particular since both involved patients had never visited tropical countries. The Robert Koch Institute registered only 205 cases of Dengue fever in Germany in 2020 [3].

No symptoms or laboratory findings suggestive of another systemic infection were found. In our two patients, no other cause of COVID toes and fingers was evident apart from the vaccination against SARS-CoV‑2.

However, future climate change and the invasion of vectors such as Aedes may increase the risk of vector-borne diseases in Europe as well. Medical doctors should be aware of this [4].