No abstract

The rapid development and the launch of several novel COVID-19 vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an extraordinary and remarkable accomplishment of modern science. The Pfizer-BioNTech BNT162b2 was the first vaccine to be granted temporary authorization for emergency use by the Medicines and Healthcare Products Regulatory Agency (MHRA) in the U.K for the treatment of COVID-19 on 2 December 2020. 1 Soon after, on 11 December 2020, it also received emergency use authorization (EUA) by the U.S. Food and Drug Administration (FDA). 2 EUA is a mechanism to facilitate the availability of vaccines during public health emergencies, such as the current COVID-19 pandemic. Under an EUA, the FDA may allow the use of unapproved medical products (including vaccines) to prevent serious or life-threatening disease when certain statutory criteria have been met and no adequate and/or approved alternatives are available. The authorization of BNT162b2 was followed by an EUA for a second COVID-19 vaccine, the Moderna mRNA-1273 on 18 December 2020. 3 This was followed by the authorization of mRNA-1273 for use by other regulatory agencies such as the European Commission, UK MHRA, Israel Ministry of

No abstract

The present psychophysical study demonstrates that repetitive noxious thermal and scratching stimuli inhibit itch and do not require direct physical interaction with the area of the skin from which itch originates.

The aim of this study was to assess the effect of thermal stimuli or distal scratching on skin blood flow and histamine-induced itch in healthy volunteers. Twenty-one healthy volunteers participated in the study. Baseline measurements of skin blood flow were obtained on the flexor aspect of the forearm. These measurements were compared with skin blood flow after various stimuli: heating the skin, cooling the skin, noxious cold 2 degrees C, noxious heat 49 degrees C, and scratching via a brush with controlled pressure. Afterwards histamine iontophoresis was performed and skin blood flow and itch intensity were measured immediately after the above-mentioned stimuli. Scratching reduced mean histamine-induced skin blood flow and itch intensity. Noxious heat pain increased basal skin blood flow but reduced histamine-induced maximal skin blood flow and itch intensity. Cold pain and cooling reduced itch intensity, but neither affected histamine-induced skin blood flow. Sub-noxious warming the skin did not affect the skin blood flow or itch intensity. These findings suggest that heat pain and scratching may inhibit itch through a neurogenic mechanism that also affects skin blood flow.