Coronavirus infection has an impact on several aspects of everyday life including the levels of Physical Activity (PA). Investigators wish to (1) detect changes on PA levels in recovered SARS-CoV-2 (COVID-19) adults compared to the pre-infection levels and (2) identify a potential relationship between changes of PA levels and pre-illness vaccination profile along with individual's number of infection/reinfections. It is assumed that the impact of COVID-19 infection on PA would be more pronounced in cases of repeated infections and/or in the unvaccinated compared to the vaccinated individuals against COVID-19.

Coronavirus identified in 2019, SARS-CoV-2 (COVID-19), has caused a pandemic of respiratory illness in which manifestation ranging from asymptomatic presentation to critically illness with severe pneumonia, acute respiratory distress syndrome, respiratory failure, or multiple organ failure. It may influence several aspects of everyday life including the levels of Physical Activity such as walking, cycling, sports or active recreation and, thus, has negative effect on general health and quality of life. Recent findings demonstrate a relation between COVID-19 infection and impairment in functional capacity, and suggest that may also be associated with an increased risk of acute and post-acute death. Moreover, individuals who have been infected might suffer long-term consequences as a result of their infection (Long COVID), for few weeks (short term) or 10-20 weeks (medium term) or more than six months (long term) post-infection.

The current study is designed to assess changes in PA (overall and in four domains i.e. daily occupation, transportation to and from daily occupation, leisure time activities, and regular sporting activities) caused by COVID-19 infection (i.e. in the short term, 4 weeks post infection) concerning the pre-illness vaccination profile and the number of infections/reinfections using a web-based validated questionnaire in a large population of Greece. Investigators hypothesize that the impact of COVID-19 infection on PA levels would be more pronounced in cases of repeated infections and/or in the unvaccinated compared to the vaccinated individuals against COVID-19. With regard to the potential burden of COVID-19 in functional capacity, investigators wish:

1. to detect changes on PA levels in recovered COVID-19 adults compared to the pre-infection levels as a result of a post-effect impact;
2. to identify a potential relationship between changes of PA levels and pre-illness vaccination profile along with individual's number of infection/reinfections so as to detect correlations amongst different parameters.

The Greek version of the revised Active-Q (AQGR) which is a self-reported, online, interactive physical activity questionnaire that assesses adult's habitual activity on weekly basis (in four main PA domains: daily occupation, transportation to and from daily occupation, leisure time activities, and regular sporting activities) is employed. Regarding questions of medical treatment during COVID-19 infection, individual's number of infection/reinfections and other relative parameters, additional questionnaire items have been incorporated. In total, the current web-based questionnaire consisted of 60-67 questions, based on previous responses and follow-up patterns, and will be extensively used to address the aims of the current study.

Inclusion Criteria:

COVID-19 recovered individuals aged from 18 to 80 years old.

Exclusion Criteria:

Individuals without any confirmed COVID-19 infection, severe musculoskeletal problems, cognitive impairment/dementia, participation in any strict weight loss control program, gestation or childbirth within one year of the study's start date.

COVID-19 recovered individuals aged from 18 to 80 years old who are residents of Greece and have been diagnostically confirmed with COVID-19 infection and recovered at least one month before answering the survey instrument.