A comparative analysis of control measures on-board ship against COVID-19 and similar novel viral respiratory disease outbreak: Quarantine ship or disembark suspects?

Background: Management of novel viral respiratory disease outbreak on-board a ship with person-to-person transmission can be a public health challenge because of close proximity of inhabitants due to confined space and air-conditioned environment. It has a potential to be explosive, with high secondary attack rate (SAR) and cause significant morbidity and mortality. This study compares control measures instituted on-board two ships with similar outbreaks and recommends a standardized evidence-based outbreak response against them.

Methods: This is a descriptive study, showing comparative analysis of control measures instituted on-board two ships, a cruise ship in case of COVID-19 and a warship in case of H1N1 influenza, with novel viral respiratory disease outbreak, at different span of time. Data of the date of onset, clinical details, laboratory results, history of travel, history of contact with positive case and control measures initiated were collected, analysed and compared.

Results: Of the two ships compared, one was a cruise ship with 712 COVID-19 cases, with an attack rate (AR) of 19.2% and 13 deaths, and other a warship with 14 cases of H1N1 influenza and an AR of 4.83%. The epidemic curve for both the outbreaks was plotted to study time distribution.

Conclusion: Active surveillance, early self-reporting and immediate disembarkation of the suspects, along with strict compliance of hand hygiene, cough etiquettes and disinfection enhancement, will help in early mitigation of the outbreak. Health education should be undertaken to impart evidence-based knowledge and alleviate fear of the unknown. Vaccination may not be present but if available should only be administered after strict risk-benefit, cost-benefit and effectiveness analysis.