Quarantining passengers on a cruise ship has backfired, and we must learn lessons

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At last count, 71,523 people worldwide are known to have been infected with novel coronavirus, and 1,770 have died.

Of that total, only 781 cases and five deaths have been detected outside China. More astonishing still is that almost half of the cases of COVID-19 outside China – 355 to be precise - are in a single location, the cruise ship Diamond Princess.

The boat was quarantined on Feb. 5 after an 80-year-old passenger who had disembarked in Hong Kong tested positive. Since then, the number of infected has soared.

Clearly, the quarantine isn’t working. If anything, it has backfired, the Diamond Princess becoming a 19-storey-high incubator for the spread of disease rather than a containment vessel.

A number of countries, including Canada, are now scrambling to evacuate their nationals inhabiting the cruise from hell.

Until Saturday, countries quietly backed Japan’s decision to keep everyone on the ship – which is docked outside Yokahama – unless they tested positive. (Those who test positive are transported to hospitals and land-based quarantine facilities in Yokohama, including 15 Canadians, three of whom are in hospital.)

But news of 70 new cases on the boat in a single day caused an about face. The U.S. immediately dispatched military flights to evacuate its nationals, and Canada followed suit. Foreign Affairs Minister François-Philippe Champagne said the intention was to “lighten the burden on the Japanese health-care system." That’s the diplomatic explanation.

In public-health circles, there are pointed questions being asked about whether the 3,711 passengers and crew aboard the Diamond Princess should have been quarantined in the first place.

This is the largest quarantine of a ship since the 1918 influenza epidemic. Since then, quarantines have largely fallen out of favour because the Great Influenza taught us that confining sick people with healthy ones actually helps viruses spread more rapidly.

Cruise ships are floating Petri dishes at the best of times – people living in close quarters, with often-windowless rooms, shared bathrooms, communal meals, and much mingling and germ-sharing.

It’s hard to imagine more ideal conditions for pathogens to spread, especially to those at high risk, such as frail elderly and those with chronic health conditions. That’s why we all-too-routinely read about outbreaks of norovirus, a rapidly spreading gastrointestinal bug that causes vomiting and diarrhea, on these big boats.

When the Diamond Princess was first quarantined, there were only five cases of the coronavirus. Now, there are 355, and counting.

It is not entirely clear when people were infected because the coronavirus has an incubation period (a time when a person is infectious but has no obvious symptoms) of up to 14 days.

But it’s looking like a lot of people contracted the illness after the ship docked 11 days ago.

The most likely vectors are the crew members.

A cruise ship like Diamond Princess is the size of small town, and has a crew of 1,045, people who have to routinely bring meals to passengers, clean the bathrooms, and so on. Crew also share quarters so can’t isolate themselves if they feel ill.

At least 15 members of the crew are known to have contracted the coronavirus, even though they are generally young and healthy (in contrast to most of the sick passengers.)

Hindsight is 20/20, so we have to be careful to not judge Japanese public-health officials too harshly. The Diamond Princess had already been turned away by five countries and Japan did the world a favour by allowing it to dock and let the sick benefit from the country’s superlative medical system.

In retrospect, however, the cruise-ship’s passengers probably should have been moved to land-based facilities that were less crowded, and where staff could wear proper protective equipment. But housing 3,700 potentially infectious people is a massive undertaking. The passengers should also have been evacuated to their home countries much sooner, and that’s on us.

While the Diamond Princess is getting all the media attention, there is another cruise ship, MS Westerdam, where a passenger tested positive for the coronavirus on the weekend – but only after most of the passengers (including 250 Canadians) had disembarked in Cambodia and scattered.

We will, in the coming days, find out if that will result in more or less spread of disease than the quarantined ship. A living experiment, if you will.

To a large extent, COVID-19 is a global public-health experiment, one dragging us into uncharted territory with each passing day.

The best we can hope for is that we learn some valuable lessons for responding to outbreaks, chief among them if and how to use quarantine measures.