These group participants received two intradermal injections with the newly developed device, one in the forearm and one in the upper arm (deltoid region).

These group participants received one intramuscular injection in the upper arm(deltoid region) using needle and syringe and one intradermal injection in the forearm using the newly developed device.

This injection is conducted by the newly developed device.

Each of the volunteers was asked to complete two questionnaires: first questionnaire surveyed demographic parameters, including gender, age, health care related job or education, number of vaccinations and blood samples taken during the last 5 years, second questionnaire surveyed the experience of ID and/or IM injection, such as anxiety, pain during injection and duration of injection. Also the perception of the participant towards injections into the forearm, which could be perceived as an unnatural site for vaccination, and perception towards the need to undress for IM vaccination, i.e. preparing the upper arm for injection, was asked. The Visual Analogue Scale (1=no agreement; 10=full agreement) was used to score the statements.

Volunteers were asked to fill a daily electronic diary for 5 days after the injections. The diary surveyed the presence of local reactions (pain at injection site, redness, swelling, ecchymosis and hardening) and systemic adverse events (headache, malaise, chills, myalgia, arthralgia, weakness/fatigue and temperature). In case of local reactions, participants were asked to measure the size of the reaction (in mm). For this purpose, a transparent ruler was provided to the participants at the study day.

At the end of a study day, the nurses performing the injections received a questionnaire that assessed the usability of VAX-ID. The nurses were requested to rate the attractiveness, handling, solidity, safety and ease of use. Some questions assessed their experience relating to painful(ness), speed and injection sites. Also their thoughts on the usability by non-medical staff (with or without any manual) and on self-administration by patients were inquired.

The Visual Analogue Scale (1=no agreement; 10=full agreement) was used to score the statements. An expert panel was organized in order to gather additional comments, remarks and proposed improvements on the use of the VAX-ID.