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Why It’s Critical For Ships To Screen Crew For COVID-19 BEFORE Boarding To Fulfill New EU & IMO Guidelines

Posted on 14th April 2020

Because ships are at high risk of COVID-19 infection in port during crew changes, the EU & IMO recently issued urgent new guidelines requiring ships to implement pre-boarding screening of seafarers to help combat the escalating problem. The effect of an outbreak on a ship would be catastrophic in business and human terms. No-one wants a medevac, major diversion or let alone a preventable death to deal with, on top of everything else they’ve got on at the moment.

Compared to workplaces in most other industries, ships crew are subject to increased risks from COVID-19 due to being confined in small spaces for extended periods of time in close proximity to other people. Furthermore, given the overwhelming dominance of male seafarers, and the fact that studies1 in Italy and Spain have shown approximately twice as many men as women die from COVID-19 as men, the dangers are intensified.

As we learn more about this disease there’s an increasing knowledge bank that shows a high proportion of infected people who are highly contagious, show no symptoms:

  • A study2 into the outbreak on cruise ship Diamond Princess estimated that 20.6% – 39.9% of cases were asymptomatic
  • According to the CDC, ~25% of cases show no symptoms.
  • A study3 of the infected Japanese evacuees from Wuhan showed that 41.6% were asymptomatic
  • An article8 in the British Medical Journal reports that four-fifths of cases are asymptomatic!

According to McKinsey4, studies in China & Singapore report that asymptomatic transmission may account for ~50% of cases. As China begins to return to work and daily life, they still experience small outbreaks and new cases. It’s widely accepted that the asymptomatic carriers are those who contribute largely to the ongoing spread – often referred to as the “super spreaders”.  This is why testing is being widely introduced as the best practice to adopt, to prevent spread. South Korea did so well at controlling the COVID-19 outbreak because they immediately began testing hundreds of thousands of asymptomatic people.

Therefore, without extensive pre-boarding screening, it’s impossible to know whether new asymptomatic crew are bringing COVID-19 onboard and infecting the whole ships’ crew.

European Commission “Guidelines on protection of health, repatriation and travel arrangements for seafarers, passengers and other persons on board ships” 8thApril 20205

So, it’s beyond doubt there’s a significant possibility that asymptomatic yet highly contagious new crew (who have the disease) could board and infect the whole of ships’ crew. This is a key reason behind the European Commission publishing new guidelines centred around protecting the health of seafarers and introducing new requirements for the pre-boarding screening of crew.

Key paragraphs of the text are extracted below:

  1. In line with the advice referred to in paragraph 3, the primary option to ensure that seafarers at risk of infection with COVID-19 can start their duties should be testing before embarking. 
  2. For seafarers with suspected infections and mild symptoms, testing should be performed in the next port of call and all crew members should have access to adequate medical care. As part of this, the person or persons in question should be evacuated and receive adequate medical care. If one person on board is suspected to be infected with COVID-19, all crew members should observe a 14-day quarantine, either onboard or land. This should be waived if the test of the crew member with the suspected infection is negative or after the quarantined crew member tests negative for COVID-19.

These guidelines follow similar directives issued by the International Maritime Organisation contained within IMO Circular Letter No.4204/Add.4 “ICS Coronavirus (COVID-19) Guidance for ship operators for the protection of the health of seafarers” 5th March 20206

 “All ships are advised to…. implement pre-boarding screening’

The new guidelines make it mandatory for ships to provide a declaration of health of all crew members, before being allowed to enter port. Going forward, every vessel’s ship master will be required to relay this information in advance:

  1. Total number of persons on board (both crew and passengers 
  2. Number of persons infected with COVID-19
  3. Number of persons suspected to be infected with COVID-19

Only ships who have the diagnostic tools to test onboard will be able to satisfy these requirements.

It’s therefore critical that vessel operators consider how to BOTH protect against infection getting on their ships AND contain any outbreak if/when it occurs. Clearly, crew change represents the highest risk of introducing an infected/contagious person on board.

Currently, there are two principal types of commercially viable test for occupational screening crew – antigen testing and antibody testing. Both kinds of tests help masters make decisions about measures to prevent and potentially contain an outbreak onboard.

Antigen tests which are often referred to as PCR tests, directly detect the virus itself using swabs from the nose and throat and have a high accuracy rate. The swab is then sent to an accredited laboratory for testing with results typically available within 1-3 days/ The International Maritime Health Association (IMHA) in April recommended7 the use of PCR tests antigen tests stating:

“If possible test every seafarer with respiratory symptoms with a throat swab (PCR) to identify if they have COVID-19.”

Furthermore, the IMO6 stated that, “Any person on board that may have been in contact with a suspected case should be…. Asked to remain onboard until laboratory [antigen] results of the suspect case are available”

Antibody tests reveal if you have been exposed to the virus, and your body has developed antibodies. They involve an affordable finger prick blood test and a small cassette onto which a drop of blood is placed, buffer solution added, and results read in just 10-15 minutes.

The new crew about to board can be categorised as follows:

  1. Totally free from any infection and never previously infected
  2. Totally free from any infection and recovered from previous infection
  3. Infected, without symptoms and within the widely accepted median 5-day incubation period
  4. Infected, past the incubation period and with symptoms
  5. Infected, past the incubation period & without symptoms
  6. With symptoms but not infected with COVID 19 (common cold)
  7. Relapsed/reactivated cases – scientists are studying this concept as ‘relapsed’ patients increase

Category 1 – subjects are of no concern and a confirmatory test will give some peace of mind to such crew & colleagues. Both types of test will likely show a negative result.

Category 2 – subjects are worthy to identify using the tests, as it’s generally recognised that these people will have developed immunity, although there remains scientific discussion on this subject as we learn more about Covid-19. PCR antigen tests will likely be negative whilst antibody tests will likely be positive. Category 2 crew members if identified, could be allocated to assist/care for any crew members that become infected whilst onboard.

Guidelines from the World Health Organisation10 recommended that a clinically recovered COVID-19 patient should test negative for the virus twice, with tests conducted at least 24 hours apart. Antigen PCR tests are the critical test for this scenario.

Category 3 – only PCR antigen tests will detect subjects carrying the virus within the 5-day incubation period – these are expensive, and results take at least 1 day to be received. Antibody tests would be negative for this category. The IMHA7 policy guidance states, “Testing a person with no symptoms by a throat swab (PCR) is never indicated. Testing asymptomatic people [using PCR] is a waste of valuable resources”

It’s therefore important for ships to anticipate the potential for category 3 subjects and define a screening strategy to mitigate any risks – see later. It’s highly recommended that ALL CREW ARE RE-TESTED 5 days after crew change to diagnose any who’ve progressed from category 3 to categories 5 see below. On-board instant antibody tests offer utility value in this scenario.

Antibody tests detect the presence of immunoglobulins which are produced by white blood cells as an immune response to viruses.  Immunoglobulin M (IgM) is the first antibody to be made by the body to fight a new infection. IgM rises within the first week of infection AFTER the incubation period and is detectable after 3-5 days. At this time the subject has the disease and is highly infectious. They may or may not be showing symptoms.  The IgG immunoglobulin, which is more abundant appears later, signally that antibodies are present which are responsible for longer term immunity.  But again, the subject may or may not show symptoms.

Dr. Deborah Birx, the response coordinator for the White House coronavirus task force, has called antibody tests “critical” in the response to the pandemic.

The below figure explains the important role antibody screening tests can play in preventing COVID-19 outbreaks on ships.