In 2021 and following the COVID-19 (corona virus disease 2019) pandemic, different vaccines were initially authorized in Italy and Lebanon. Notably, vaccine side effects were poorly recorded. Thus, the investigator performed a survey study to monitor COVID-19 vaccine side effects among Italian and Lebanese citizens according to gender and age through a web-based questionnaire in Italian and Arabic languages including 21 items by "Google Form", investigating 13 symptoms, and employing social-media platforms

The COVID-19 pandemic has presented a real challenge to the public health system worldwide since the year 2019, spreading to more than 200 countries and regions worldwide.The emergence and rapid spread of COVID-19 were caused by the coronavirus SARS-CoV-2. Worldwide, the use of COVID-19 vaccines was initially authorized for emergency use and the side effects were not stated clearly. Common side effects were expected but specific side effects linked with COVID-19 vaccines remained uncertain. In this context, survey studies are needed for a comprehensive evaluation of the relationships between vaccine administration, related undesired effects and vaccine safety.

This study represents the first survey following early COVID-19 vaccines administration in two geographic areas, comparatively considering possible differences due to gender and age. A web-based survey was conducted on a cohort of 1975 Italian and 822 Lebanese people who received at least one dose of COVID-19 vaccine. The study was conducted between March and July 2021 on a voluntary basis, and by a tailored anonymous web-based questionnaire. The protocol was approved by the local Ethics Committee, University of Bari 'Aldo Moro' (study number 6752, protocol number 0031044). A specific questionnaire was designed in English and translated into Italian and Arabic. It contains 21 items including demographic data, the history of vaccine administration before COVID-19, the administration of the first and second dose of COVID-19 vaccine, and possible adverse effects.

The survey link was shared by a "Google Form" employing social-media platforms or by personal interview.

The questionnaire explored the presence of 13 possible symptoms appearing following the administration of the first and second dose of COVID-19 vaccine: pain at the injection site, redness at the injection site, swelling at the injection site, induration at the injection site, allergic-urticarial reaction, anaphylaxis, fever (>37 °C), diarrhea, vomiting, asthenia/fatigue, muscle pain, rash, sleepiness/insomnia, irritability/nervousness, headache, lymphadenopathy. The presence and intensity of symptoms were assessed semi-quantitatively by a Visual Analogue Scale (VAS). Besides symptoms, the following aspects were also evaluated: need of drug intake, consultation of a doctor, emergency admission to hospital, and possible hospitalization.

Inclusion Criteria:

• Anti-COVID-19 vaccine

Exclusion Criteria:

• Subjects who living outside Italy or Lebanon

Random sample from the Italian and Lebanese population who received first or first and second dose of anti-COVID-19 vaccine