Ports have a long history of sanitary threats as they represent gateways to the intercontinental flows of people. As passengers can spend several days on a ship, there is ample time for a disease to be transmitted and noticed. If many cases are present on a ship, quarantine measures are implemented, effectively isolating the ship until the infection would run its course. The growth of international air travel from the 1960s, particularly jet planes, has shifted concerns about sanitary threats away from ports.
However, local sanitary risks have been recurrent in ports, and have disrupted their workforce. Port workers were also impacted each time an epidemic or pandemic occurred. New threats have emerged with the growth of cruise shipping and the growing number of passengers spending time at ports and on cruise ships. The most frequently reported cruise ship outbreaks involve respiratory infections (e.g. influenza), gastrointestinal infections (e.g. norovirus), and vaccine-preventable diseases (e.g. varicella, measles, chickenpox).4
When the COVID-19 pandemic began in early 2020, the first cases of infection reported outside China were on cruise ships calling at Chinese ports. In February 2020, the Diamond Princess, operated by Princess Cruises, was reported to be the first cruise ship to be impacted by the COVID-19 pandemic. Quarantine measures were implemented at ports where ships were allowed to dock. Later, as the cruise industry was shut down, concerns rapidly shifted to port workers who judged to be essential workers and needed to maintain supply chains. Sanitary measures, such as protective equipment, were implemented to keep the workforce operating in safe conditions.