|Year : 2020 | Volume
| Issue : 3 | Page : 1-5
Not the last pandemic – Investing in a safe navy for the future pandemic
Sougat Ray1, Sunil Goyal2, Kaushik Roy3, Naveen Chawla1, RJ Singh1
1 HQWNC, Mumbai, Maharashtra, India
2 INM, Mumbai, Maharashtra, India
3 IHQ of MoD (Navy), New Delhi, India
|Date of Submission||27-Sep-2020|
|Date of Decision||28-Sep-2020|
|Date of Acceptance||30-Sep-2020|
|Date of Web Publication||31-Oct-2020|
Surg Capt Sougat Ray
HQWNC, Naval Dockyard, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Ray S, Goyal S, Roy K, Chawla N, Singh R J. Not the last pandemic – Investing in a safe navy for the future pandemic. J Mar Med Soc 2020;22, Suppl S1:1-5
| Background|| |
With 50 million deaths worldwide, the loss of life caused by the influenza pandemic of 1918 far exceeded that in the first world war. Drugs were unavailable, and vaccine was still a dream. A century after, COVID-19 came as an unexpected crisis for the still unprepared world. The virus continues to spread at a slow burn; intermittent lockdowns are the new normal, and global economy is sinking. Although an estimated 30 million people have been infected worldwide, and 1 million are dead, early projections were much worse. The public health strategies have saved the millions of lives. However, the world needs smart investments now to navigate through the present situation and simultaneously prepare for any similar future threat.
Ships are the perfect petri dishes for the transmission of a novel air-borne virus and the maritime domain complicates efforts to limit its spread. The naval service across the oceans has grappled with the surge of clusters of COVID cases. It has struck down aircraft carriers more effectively than any complex system of surveillance and firepower ever could. Limited evidence exists on the incidences of COVID or other airborne disease outbreaks, which have posed an operational threat in the Maritime environment till date. The USS Roosevelt, where the outbreak occurred during the 1st week of March, had confirmed approximately 1000 COVID-positive cases (approximately 1/3rd of the total crew) at the end of the outbreak which lasted for around 2 months. In the French carrier Charles de Gaul, a similar proportion of sailors had tested positive with the outbreak lasting for around 6 weeks. The index case onboard the Diamond Princess was detected on January 25, 2020, and within approximately 30 days, out of 3,711 passengers and crew, 712 (19.2%) were positive. Of these, 331 (46.5%) were asymptomatic and among 381 symptomatic patients, 37 (9.7%) required intensive care and 9 (1.3%) of them died. The outbreak onboard the naval aircraft carriers and the cruise ship occurred relatively early in the pandemic. Initial contacts were quarantined onboard, and there was a delay in removing the contacts from the ships resulting in the rapid spread of the infection and subsequent high morbidity. The COVID pandemic has exposed the need for practical solutions toward the emergence of nontraditional threat as a key issue in the security system.
This editorial describes the nuances of dealing with a biological threat in future, analyses the best practices and evidences which have emerged while dealing with the current COVID-19 pandemic and recommends future investments which will mitigate such a situation in the Navy. The interventions have been divided into three categories [Table 1]: outbreak control on-board, considerations for future ship design, and establishment of Biosafety Level 3 (BSL-3) Isolation Wards in hospitals.
|Table 1: Prospective measures for dealing with Air-Borne Bio-threat/Pandemic in Navy|
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| Biological Warfare|| |
The defence forces have been preparing for a possible biological warfare by training the troops in the use of protective masks and equipment and administering vaccines on possible known agents. Approximately 150,000 US troops received a toxoid vaccine against anthrax, and 8000 received a botulinum toxoid vaccine before specific operations. For further protection against anthrax spores, 30 million 500 mg oral doses of ciprofloxacin were stockpiled to provide a 1-month course of chemoprophylaxis for the 500,000 US troops that were involved., Entry of biological agents in the form of an airborne infection into the Maritime domain poses a heightened risk due to the close environment and in case of a highly infectious novel virus, there is no innate immunity, no drugs and no vaccine, hence, known mitigation measures might be futile or ineffective.
| Airborne Versus Droplet Transmission Onboard Ships|| |
A highly infectious airborne disease spreads rapidly from person to person through respiratory droplets which are larger entities (>5 μm) or by aerosols which are smaller particles (≤5 μm). It may cause serious life-threatening consequences, presents a serious hazard in the health-care setting and in the community, and requires immediate, specific control measures. Respiratory droplets rapidly drop to the ground, typically within 3–6 feet of the source person. Aerosols, being smaller particles evaporate in the air into the ventilation system of ships and submarines, leaving behind droplet nuclei that are light enough to remain suspended in the air in a compartment for hours. Ships crew work in tight spaces, share common spaces, and sleep in tight quarters. If an airborne infection is primarily spread by respiratory droplets, wearing a medical mask, face shield, or keeping 6 feet apart from other individuals should be adequate to prevent the transmission. However, if it can pass through the ventilation system to other compartments in the ship or remain suspended in the air in a close compartment, all personnel onboard with the same ventilation system will get affected. In a study in diamond princess, it was found that the incidence of the infection in cabins with a previous case was not significantly higher than that in cabins without a previous case or a contact indicating both droplet and aerosol transmission onboard the ship indicating transmission through the ventilatory ducts. Similarly, onboard USS Roosevelt after the infection was controlled, it was found that 65.6% individuals who tested positive reported sharing a room with a positive case, indicating that though infection was primarily due to close contact, while one third of the infection did take place outside the same living compartments signifying aerosol transmission.
| The Asymptomatic Conundrum|| |
Disease control strategies should be implemented to account for the substantial asymptomatic and subclinical transmission associated with most air-borne infections. A study carried out on a sample of 382 sailors onboard USS Roosevelt found that 228/382 (60%) had seroconverted to IgG positive, with 20% of them being asymptomatic. Studies conducted on the previous pandemic of severe acute respiratory syndrome indicated similar asymptomatic transmission (13.3%) through close contacts in a household. Moreover, in some air-borne infections such as COVID-19, a person becomes infectious 2–3 days before the onset of symptoms, making the control of transmission on-board a real challenge. The disease could be spreading among the unsuspecting crew till a case is detected, but by which time many more would have been infected. In such scenario, it is of paramount importance to rapidly control the outbreak on-board, to safeguard the well-being and morale of the crew and simultaneously to ensure maximum operational readiness.
| Planning for Isolation Facilities Onboard|| |
The Sick Bay of a ship is ventilated by positive pressure in relation to adjacent compartments surrounding the complex to prevent ingress of any possible contaminated air from outside the compartment and thus maintaining asepsis inside the sick bay. However, an isolation compartment onboard needs to maintain a negative air pressure in relation to the surrounding, so that contaminated air from the ward, where an infected individual is isolated, is prevented from entering the external environment and transmit to others. These isolation compartments should either be prefabricated onboard ships [Figure 1] or negative pressure zones be created in designated compartments by throttling the air in that compartment to convert it to an isolation facility during an airborne disease outbreak.
|Figure 1: Schematic diagram of a 4-bedded isolation ward onboard ships. The air entry should be high-efficiency particulate air filtered. The resulting four-bed unit along with ante room allows for unidirectional flow of providers and materials and has ample space for an onsite laboratory and donning and doffing personal protective equipment|
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| Outbreak Control|| |
The warships and submarines are not designed for the space to keep them light and maneuvrable. Work spaces are packed to the gills with machinery, weapons, and systems. Living spaces are equally cramped. Most ships, including the cruise ships, have common ventilation system with separate air filtration units. Chances of airborne outbreaks increase because of the close confines and same ventilation.
A robust approach would be to prevent the entry of an agent into the micro-environment of the ship by the creation of safe sea bubbles when the pandemic is ongoing. Effective quarantining of personnel who are entering from outside, for the maximum incubation period, before embarking the ship is a safe strategy. Creation or extension of earmarked infrastructure for this requirement needs to be accounted in annual readiness plans. These personnel may preferably be tested with the available field-based test prior sailing. During this period, interaction with external agencies is to be avoided but if compulsorily required, an interface cohort may be formed who enter the ship for daily work, do not mix with quarantined crew and stays ashore.
Aggressive protocols ,, are required during sailing to control an outbreak of an air-borne disease [Figure 2] as it can rapidly spread and cause debilitating illness compromising the operational capability during a mission. The protocol of identification and isolation of cases; tracing and quarantining the contacts would work perfectly in such situations as have been observed in previous studies. Active surveillance to identify further cases should continue. Negative pressure isolation facilities are to be created on board for isolating the cases. Quarantine facilities could be identified before sailing. Preventive measures of disinfection, universal wearing mask, touchless techniques for handling of objects, and staggered timings for meals and toilets are the necessary measures. The confirmed cases are to be disembarked at the earliest by fastest possible means. Experience from Diamond Princess showed that since the day isolation and quarantine procedures were introduced, transmission came down from one person infecting more than seven person to below one.
|Figure 2: Test and disposal guideline to contain an outbreak of air-borne infection while sailing during a bio-threat/pandemic|
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| Future Hospital – high-Level Isolation Units|| |
Victims of a yet undiscovered contagious infectious agent will require safe, secure, top-notch medical care with advanced infection control protocols, which may be most effectively delivered by specially trained staff in the setting of a high level isolation unit (HLIU). The unit should be a negative pressure ward (−50 Pa) with single-bed rooms and an anteroom located away from other clinical areas. The air intake is to be high efficiency particulate air (HEPA) filtered and expelled externally and the number of air changes is at least 12 per hour. The depressurization of the unit is to be monitored by an audible and visual device as recommended by the American Institute of Architects. This air-handling system allows the treatment of airborne infection and prevents its spread by contact, droplet, or airborne routes of transmission., Ideally, the HLIU should be accompanied with an anteroom with onsite laboratory next door and an autoclave waste management system to minimize the transport of infectious materials out of the unit. For patient transportation, two fully equipped ambulances and two stretcher isolators with a negative pressure section should be available.
Stringent infection control protocol is critical to prevent transmission to health-care workers and other patients. Droplet precautions (e.g., surgical or procedure mask, gown, and gloves) are indicated during the treatment. Additional precautions may also be appropriate during aerosol-generating procedures in the hospital.
| Conclusion|| |
The current crisis calls for a clear and coordinated template to approach a large scale and prolonged nontraditional security threat like a pandemic which has the potential to disrupt naval operations. The challenge is to keep the personnel battle ready at sea and safe for a sustained duration. Thus, there is a requirement to bring in structural reforms in existing platforms and catering for such needs in the future ship design. Suitable infrastructure for expansion of in-living space ashore needs to be simultaneously catered. High definition isolation facility within the hospital complex is the need of the hour as it will allow control of the disease in the health-care settings and preserve the scanty health workforce. Capacity building and strategic positioning of epidemiological response teams at command levels to mitigate such crisis should be planned. A robust stockpile of medical supplies and emergency supply chain will have to be maintained. The experiences from COVID-19 present an opportunity and an urgency to re-invest in public health activities. Mitigation of biological threats is one of the key challenges in the national security system. It is imperative therefore to make necessary structural and behavioral modifications based on the best practices and lessons learnt to handle such nontraditional threats in future by the navy.
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[Figure 1], [Figure 2]