Regional health security describes the capacities required for CARPHA Member States to prepare for and respond to public health threats, issues and concerns that transcend national boundaries and potentially impact on economic and political stability, trade, tourism, and access to goods and services. Infectious diseases, whether they be endemic, emerging or re-emerging, naturally occurring or a manmade threat, continue to cause illness and death globally. In the Caribbean, infectious diseases such as human immunodeficiency virus, cholera, dengue fever, foodborne diseases, antimicrobial resistant organisms, severe acute respiratory syndrome (SARS), and the pandemic causing influenza A(H1N1)pdm09 virus, have all been major causes of epidemics, multiple local, regional and global outbreaks and severe diseases, at times leading to death. The epidemic of Zika (2016), Chikungunya (2014), the Hurricanes of 2017-18 and other threats show the need to have good systems of regional health security, especially given the region's tourism dependent economies. Communicable diseases are also linked to chronic diseases. Infectious agents can cause cancer and other long term debilitating illnesses. For example, following an acute episode of chikungunya a high percentage of patients can develop a chronic phase defined by persistent arthritis for months or even years. Therefore, in addition to imposing enormous financial burdens on societies and stretching local and regional health and public health systems in low and middle income countries, these and other public health threats have highlighted the importance of strong national public health systems that can contribute to health security in the region, and globally. Infectious diseases continue to present significant health, social, economic and development challenges.