On the Use of Theories in Study of Personal Health Behavior During
Epidemics/Pandemics.

Abstract
Communicable diseases pass all the geographical and political boundaries as a result of globalization, population movement, and international trade regime. Every year, the WHO publishes a long list of new disease outbreaks. Thus, COVID-19 is not the last and the only disease that requires adjustment in health behavior and public participation. During an epidemic/pandemic, different countries design new and different public health measures to protect their own population. However, people may choose to follow these new policies or ignore them. Choosing to ignore them jeopardizes the effect of new public health policies and counteracts all the efforts of healthcare providers. This theoretical paper attempts to provide a theoretical foundation for personal health behaviors during an epidemic/pandemic by providing evidence from the current COVID-19 outbreak. This paper covers the main theoretical aspects from the epidemiological transition decision-making process, health belief model, optimism bias, conspiracy theory and trust, stigmatization and super-spreader, and social determinates of health in three levels (from individual level to social and contextual level), which can allow us to understand personal health behavior during epidemics/pandemics.


Introduction
Emerging and re-emerging diseases are always considered as one of the main global health threats, for which there is generally no treatment or vaccination outbreak as a pandemic for which all countries should take responsibility to prevent or slow down the spread of the disease. This pandemic has affected the lifestyle of many people around the world, resulting in the need to practice new policies such as social distancing, travel restrictions, cancellation of public gatherings, and quarantine on a very big scale, which has never been experienced before in contemporary history.
Despite the fact that many countries adopted different intervention plans and policies in response to this pandemic, these policies have either not necessarily been followed by the general public or have resulted in very harsh restrictions and lockdown of cities and countries. Individuals are also acting differently within societies, where some followed the public health recommendations, and others persist in not implementing any changes in their health behaviors during this emergency. To be able to adopt and apply any sufficient health policy, it is essential to predict public health behaviors, which are mainly based on individuals' socio-economic status, values and beliefs, trust in their political or health care leaders.
This paper attempts to provide a theoretical foundation on health behaviors of individuals during epidemics/pandemics.

Epidemiologic Transition
Epidemiologic transition theory was first addressed by Omran (1971), describing the changes in the patterns of diseases from communicable/infectious diseases to more non-communicable and man-made diseases.
According to Omran (1971), this transition includes three main stages. The first stage is the "Age of Pestilence and Famine," which is the period of infectious disease when there are no modern medical treatments, vaccinations, and medicines available.
Stage two is when the peak of the pandemic is declining due to the introduction of basic public health policies (hygiene and public vaccination); thus, it is called the "Age of Receding Pandemics." The third stage is the "Age of Degenerative and Man-Made Diseases," which is the period of non-communicable diseases (such as cardiovascular diseases) and health problems related to the lifestyle and health behavior, as well as diseases related to the aging of the society and degenerative disease [4]. These people are not necessary changing their health behavior, and protecting themselves and others, since they have a cognitive bias; thus, they cannot find any justification or rational for any health protective behavior.

Keeping it Secret and Super-Spreaders
Health protective behaviors after being diagnosed   [44][45][46]. In addition to age and gender, there is a positive association between education and health protective behavior [47]. Education increases the likelihood of accessing health information, and adopting health-protective behaviors [48]. In uncertain situations and emergencies, there is always a risk of misinformation and unverified information regarding the epidemic [49][50][51]. Therefore, education plays a very important role in health informationseeking behavior. Health information-seeking behavior is the first step for health-promotion and health-protective activities [52].

Social Determinants of Health
The other important factor related to the spreading disease is household and neighborhood characteristics [48]. This can be due to lack of awareness related to protective behavior due to the language barrier, living in low-income neighborhoods and its consequences, and limited access to information and hygiene items [58,59]. However, it needs to be noted that migrants and ethnic minorities are not a homogeneous population and they may act differently during an emergency [59].
Another personal health protective behavior variable that needs to be taken into consideration during epidemics/pandemics is the risk factor that contributes

Conclusion
This is a theoretical paper that provides a theoretical