It was one of the first outbreaks of coronavirus to capture global attention: For weeks in February, the cruise ship Diamond Princess was moored off the shore of Japan with hundreds of infected people aboard.
Then in early March, nearly 2000 passengers had to be quarantined on US military bases after infected passengers were found on the Grand Princess, a sister ship operated by Carnival Corp-owned Princess Cruises.
By the time major cruise lines halted new voyages last Friday, at least half a dozen other ships had sailed, and at least one passenger was later diagnosed with the highly contagious virus.
While cruise lines have seen only a small fraction of the pandemic, they have emerged as a particularly tricky battleground to fight the virus. Health experts said the industry's initial resistance to take drastic action - coupled with a deference from government officials, who let the companies to come up with their own action plan - put more passengers at risk.
• Coronavirus: 56 New Zealanders on board cruise ship with four confirmed cases
• Confirmed Covid-19 case was on cruise ship that visited Tauranga
• Coronavirus: Luxury cruise ship Silver Muse docks in Auckland despite travel restrictions
"The cruise ship response was definitely lagging behind expert opinion on how big the risks are," University of Chicago epidemiologist Katelyn Gostic said.
"It was sluggish decision-making and they should have responded earlier."
The crisis has put the spotlight on an industry that critics say for years has skirted labour regulations, such a minimum wage, and federal income taxes by incorporating overseas. Yet when disasters strike, or when people get sick or fall overboard, federal agencies such as the US Coast Guard come to the rescue.
The Trump administration is now pushing to spend billions to prop up the cruise industry and other hospitality and travel businesses that have been crushed by the pandemic.
"Through the years, a huge amount of federal staff resources have been diverted to dealing with cruise ship health outbreaks," said Nicole Lurie, who served as a top official at the Department of Health and Human Services during the Obama administration.
"Given all the demands on public health resources, it may be worth asking about the public investment we make in protecting cruise ship passengers by putting in place better strategies to prevent future outbreaks involving cruise ships."
Cruise line officials say operators are subject to robust inspection by US and foreign regulators. And the industry has defended its response to the pandemic, noting the singular nature of the crisis.
Bari Golin-Blaugrund, a spokeswoman for the Cruise Lines International Association, said "the agility and responsiveness of CLIA cruise line members has been on full display over the past two months".
Within 24 hours of the World Health Organisation's declaration of a global health emergency, cruise line operators rapidly adopted enhanced protocols that she said "were repeatedly elevated as circumstances evolved over time".
That, along with extensive cleaning and sanitation, helped limit the number of coronavirus cases aboard cruise lines, she said.
Roger Frizzell, chief communications officer of Carnival Corp, the world's largest cruise operator and the owner of the line that operates the Diamond Princess and the Grand Princess, said cruise lines in January began barring passengers who had been to China in the previous two weeks. They later added recent travellers to Hong Kong, Macao, South Korea and regions of Italy to the no-sail list.
"To my knowledge, this was the first such restriction like this ever established in the cruise industry," he said.
"In reality, the cruise industry acted collectively and independently well before other industries when it came to the initial outbreak of coronavirus in China in December 2019."
But in the weeks following the outbreak on the Diamond Princess, major cruise lines missed several opportunities to mitigate the crisis, according to health experts and passengers aboard the vessels.
After it was clear the coronavirus was spreading around the world, passenger screening was limited. Even on cruises where officials knew of positive tests, such as the Grand Princess, strict quarantines confining passengers to their rooms were not imposed immediately.
Inconsistent deboarding procedures also meant thousands of passengers who travelled on a ship that had carried a passenger who tested positive for the coronavirus went home with little or no medical screening - possibly bringing the virus back to their communities.
And companies stopped sailing only when the pandemic had reached a crisis point, when some countries closed their harbours, leaving ships with potentially sick people adrift.
Compounding the problem was a White House reluctant to crack down on cruises as the pandemic mounted, even as some top administration officials were urging a suspension of operations before the voluntary shutdown, as The Washington Post previously reported.
Vice President Pence, who leads the coronavirus task force, touted the industry's initial plan to beef up passenger screening and quarantine protocols. "We want to ensure Americans can continue to enjoy the opportunities of the cruise line industry," he said at a March 7 meeting with industry executives.
Trump has long-standing connections to the industry, including through Carnival Corp chairman Micky Arison, a friend whose company helped sponsor Trump's reality show franchise The Apprentice over the years. On Thursday, Trump said he spoke to Arison, who had offered up his ships to house non-coronavirus patients.
The president has repeatedly said he wants to help cruise lines with a financial rescue package, along with airlines and hotels.
"You don't want to lose industries like this," he said Thursday. "These are incredible industries. You can't lose them."
Meanwhile, the Centres for Disease Control and Prevention boosted its warning this week against cruising to a higher level, advising any recent travellers to isolate themselves for two weeks. It also put local health departments on notice for the first time about six ships that carried infected passengers in the last month - which have already disembarked travellers who were then not quarantined.
Some customers and their family members now say the industry held back information and should have reacted more quickly.
"To avoid a panic that might collapse the industry, the cruise lines continued to mislead their passengers," said Ashley Ecker, whose San Diego-based parents are aboard the Costa Luminosa, which continued on a voyage across the Atlantic earlier this month after a woman, later diagnosed as positive for the virus, disembarked with breathing problems. By the time the ship reached a port in France on Thursday, five additional passengers and two crew members had flu-like symptoms.
"This needs to be investigated - certainly before we even consider an industry bailout," she said.
The cruise industry got an early warning of how easily the virus could spread on its massive ocean liners when the first cases emerged on the Diamond Princess in early February after it left Yokohama harbour.
Despite a February 5 quarantine, 700 people aboard eventually tested positive.
An initial CDC study published on Tuesday found the virus quickly spread through food service workers, particularly those cooking for other members of the crew.
"This investigation underscores the need for swift epidemiologic investigation as soon as a Covid-19 case is detected in an area or group where a large number of persons gather in a closed or crowded setting," the study said.
On February 21, as quarantined passengers were still trying to get off the Diamond Princess, Diane and Steve Houghton, of Pleasant Hill, California, were eagerly boarding a sister ship, the Grand Princess, on the other side of the Pacific Ocean, for a 15-day cruise to Hawaii.
Steve Houghton said the passenger screening in San Francisco was limited. The brief questionnaire handed to passengers as they boarded asked about fever, persistent cough or recent travel to coronavirus hotspots like China.
His document went into a stack along with hundreds of others, Houghton said.
On his form, Houghton wrote that he coughs all the time and has difficult breathing due to chronic asthma.
"No one asked any questions. They said not a single word," he said.
The ship set sail for Hawaii with about 3500 people aboard. As it passed beneath the majestic Golden Gate Bridge, passengers crammed the decks to take in the view, drinks in hand.
Several days of relaxation and merriment followed, with little or no awareness of the virus's creep around the world, according to passengers interviewed by the Post.
"We never thought coronavirus was in America. We never dreamt of it," said 65-year-old Howard Lewis, of Wales, who said he and his wife met couples aboard who had booked the cruise to Hawaii after cancelling trips to Asia.
What they didn't know: the day before, as the ship's previous voyage to Mexico was winding down, a passenger came into the medical centre "with a six to seven-day history of symptoms of acute respiratory illness," Grant Tarling, Carnival's chief medical officer, said in a call with reporters two weeks later.
Crew members and 62 passengers who had possibly interacted with that guest on the earlier trip remained aboard for the cruise to Hawaii, according to the cruise line.
Frizzell, the Carnival executive, said Princess Cruises was not aware that the passenger had been hospitalised until days after the cruise had departed. Guests had been given "a general health notice with their boarding materials as additional precaution for coronavirus as part of our company's enhanced safety and health protocol," he said.
On March 3, health officials in Placer County, California, announced the former passenger had tested positive for coronavirus.
The following morning, the Grand Princess issued a "health advisory letter" to guests that said the Centres for Disease Control and Prevention was investigating a "small cluster of Covid-19 (coronavirus) cases in Northern California connected to our previous Grand Princess voyage."
The notice said the ship was skipping a stop in Mexico and heading directly back to San Francisco. The passengers who had gone on the previous voyage were asked to retreat to their cabins until cleared by medical staff.
The coronavinus-infected former passenger died that day, becoming the state's first fatality from the virus. California Governor Gavin Newsom (D) declared a state of emergency.
But the vast majority of the about 2400 Grand Princess passengers were not quarantined in their cabins until the afternoon of March 5.
Health experts say cruise ships are fertile ground for infectious diseases because they pack thousands of people into close quarters for days at a time, encouraging them to eat and socialise together. Cruises also cater to the elderly, who are particularly vulnerable.
Amesh Adalja, an infectious disease doctor who serves as senior scholar at the Johns Hopkins University Centre for Health Security, said the positive test on March 3 should have led to a more serious response.
"The confirmed case should have triggered social distancing measures at that point," Adalja said. "Because of the high consequences of this infectious disease and attention to it in light of what happened with the Diamond Princess in Japan, they really should have been prepared for what could happen."
Frizzell said passengers "were alerted within hours" about the positive coronavirus test.
"Upon being alerted of the issue, the Grand Princess looked closely to the CDC and health officials for direction," he added.
Passengers said performances and activities were cancelled on the evening of March 4 and the following morning, but they continued to mingle at the bar and move freely around the ship.
The buffet was still open at about 1.45pm on March 5, according to Keane Li, of San Francisco, who was keeping close tabs on his parents on the ship and posting updates to Twitter.
"Given what happened on the Diamond Princess, there should've been a contingency plan for this," said Li, whose father, Wai Li, was diagnosed with covid-19 after disembarking the ship last week. "I get that they didn't want to scare anyone, but they should've acted sooner."
Kailee Higgins Ott, a high school junior from the Bay Area, said she was eating lunch in the main dining room on March 5 when the captain announced that people needed to stay six feet away from each other and then retreat to their staterooms.
"I mean, when he said social distancing, everyone like started to laugh because we were sitting in a dining room and obviously we couldn't be six feet away from everyone," she said.
On March 6, Captain John Harry Smith assured passengers he would keep them informed, according to announcements shared by a passenger with the Washington Post. An update came later that day, but not from the captain.
In a news conference at the White House that afternoon, Pence said 46 people had been tested from among the more than 3500 people on board. Among them, 21 had tested positive, 19 of them crew members.
Passengers learned there were confirmed coronavirus cases on board at the same time the public did. Smith came back on the loudspeaker.
"We apologise, but we were not given advance notice of this announcement by the US federal government," the captain said. "It would have been our preference to be the first to make this news available to you."
Carolyn Wright, 63-year-old from Santa Fe, said, she was "hearing things on the news that were affecting us directly that were never communicated to the passengers being affected. It was the most frustrating, helpless feeling".
"When all control over your personal life is taken from you and you're not even told what's going to happen to you or why or anything, the stress level is incalculable," she added.
After Pence's announcement, Carnival relaxed its policies to allow guests to cancel or postpone cruises because of potential worries about coronavirus.
The Grand Princess used a stricter protocol for distributing food and fresh towels to quarantined passengers than the Diamond Princess, which had allowed crew members wearing masks and gloves to make deliveries in person. On the Grand Princess, passengers said they were asked to wear masks when they opened their doors to retrieve meals left on the floor and said they never saw crew members.
"The stewards, the ones that came and delivered things to you, they all had their masks on," said Amy Horowitz, a New Yorker celebrating her 59th birthday on the ship with family. "They would just bang on your door to let you know they left something at your door and run away as fast as you could."
On March 9, the ship was allowed to dock in Oakland. Lewis and his wife flew home to Wales, as did other passengers from around the world, while the American passengers were sent to military bases for quarantine.
As of Thursday, more than 870 evacuees from the ship who were taken to four US military bases had been tested, according to the Department of Health and Human Services. Another 674 had declined to be tested.
Including passengers and crew who were tested while still aboard the ship, US officials said they were aware of 40 people from the Grand Princess who have so far tested positive for the coronavirus, a number that is expected to increase in the coming days, according to an HHS spokeswoman.
Houghton said he and his wife had been feeling fine and had declined testing while confined to Travis Air Force Base, stewing about the cruise line's handling of the situation.
"Princess Cruise Lines filling our ship and sailing with sick people on board was unforgivable," he said.
Other passengers from around the world who chose to be tested are now learning their results. In Wales, Lewis and his wife found out last weekend that they were infected.
"With hindsight I suppose you could say they should have quarantined us earlier, though I am not sure it would have made a difference," Lewis said. "People will learn a lot from this hopefully."
On March 5, the same day that Grand Princess passengers were being quarantined to their rooms, another cruise ship, the Costa Luminosa, set sail from Fort Lauderdale, on an itinerary through the Caribbean and onto Europe. The ship carried 1400 passengers, including 233 Americans.
Ecker, 41, said her parents Jeffrey and Kathryn Bitner were nervous about going on the trip. But she said they were assured by cruise authorities that there was no need for concern - and also warned that they would not be reimbursed if they cancelled.
"So they believed them," she said, "and they left."
Passengers did not know that during a previous voyage of the Costa Luminosa, an Italian man had complained of heart trouble and was taken off the ship in the Cayman Islands on February 29, according to Carnival-owned Costa Cruises, which operates the ship. He later tested positive for the coronavirus and died.
On the current voyage, an Italian woman disembarked March 8 in Puerto Rico complaining of breathing troubles and then tested positive for the virus. So did her husband travelling with her, the company has since said.
While it awaited test results, the cruise line did not initially tell passengers about the sick woman who got off the ship, even though she was hospitalised, relatives of current passengers said.
Instead, the ship continued toward its next port-of-call, Antigua. After authorities there denied the ship docking because of the ill woman who had disembarked in Puerto Rico, it headed out for the multiday trip across the Atlantic Ocean.
Only then, on March 9, were passengers told about the sick woman, according to a letter delivered on board, a copy of which was obtained by the Post.
Those aboard the ship continued to mingle and eat communally. By the time the Costa Luminosa reached the Canary Islands, off the coast of northwest Africa, three more passengers had coronavirus-like symptoms. They were allowed to disembark, but the Spanish government would not allow others to come ashore because Spain has closed its ports, the company said.
On March 13, the cruise company said it was told the Italian man on the ship's previous voyage had tested positive. The following day, March 14, it learned the woman hospitalised in Puerto Rico and her husband also had tested positive.
One more day passed before passengers were isolated in their rooms, according to people aboard. A full week had passed since the sick woman disembarked in Puerto Rico.
"Other measures had already been implemented in the days before, including isolation of the close contacts of the suspect cases and the cancellation of several on board activities," Rossella Carrara, a Costa Cruises vice president, said in an email.
"The health and safety of guests, crew member and of the destinations is of the utmost importance," she added.
By the time the ship docked in Marseille early on Thursday morning, five passengers and two crew members had flu-like symptoms, the company said. After French health authorities came aboard to do health checks, 386 passengers disembarked, most of them French, Canadian and US citizens, the company said.
A chartered airplane carrying US citizens landed in Atlanta on Friday morning, where additional health screenings were expected to take place. According to passengers, some were coughing during the trans-Atlantic flight.
On March 8, the State Department and the Centres for Disease Control and Prevention warned US citizens, particularly those with medical issues, not to travel by cruise ship. The move panicked industry officials, who scrambled to pull together an action plan and get ahead of further government action, according to people familiar with the situation, who spoke on the condition of anonymity to describe private discussions.
Around 6pm that day, the MSC Meraviglia pulled out of Miami for a scheduled eight-day cruise to the Caribbean.
Four days later, the MSC cruise line was informed by Canadian authorities that a passenger on the ship's previous journey had tested positive for the coronavirus, according to the cruise line. Some crew members and guests who had travelled with that passenger had remained on board for the subsequent voyage.
Passengers received notices the next day that seven crew members who might have been in contact with the virus-infected former guest were quarantined, according to a copy reviewed by the Washington Post. It did not mention possible contact with other passengers.
The ship continued, making a stop Saturday at an MSC-owned island in the Bahamas.
Jeffrey Cleary, 55, said passengers had their temperatures taken before reboarding the ship. But when they arrived back in Miami on Sunday, no one checked their temperatures, he said.
Nearly 3900 passengers streamed off the ship - many headed to the airport to fly to homes around the world.
"Not one piece of screening was done," Cleary said. "Off we went."
The cruise line had been carefully monitoring the health of crew and passengers, and none were experiencing symptoms associated with Covid-19 as the cruise ended, according to the company.
"The ship received clearance from the CDC and [the United States Coast Guard] on Sunday, March 15 after they reviewed all the necessary documentation regarding the health of passengers and crew on board on Sunday and throughout the cruise," the company said in a statement.
CDC spokeswoman Kristen Nordlund said the federal agency had been aware of the positive test before the ship was allowed to dock and responded by sending a notice to local health departments to alert them to the "medium risk" posed by the disembarked passengers.
"As the situation in the United States changes, both with increasing Covid-19 cases and the number of cruise ships coming in to port over the next few days, CDC is continuing to reevaluate how we approach returning cruise ships," Nordlund said.
Thousands of cruise ship passengers are now slated to return home in the coming days from ships whose voyages began before the industry's temporary halt.
Many of the ships that remain at sea have had difficulty finding countries that will allow them to dock, even those with no identified cases aboard.
The Norwegian Jewel, for instance, which departed Sydney on February 28, had been sailing toward Honolulu after being prevented from docking in several South Pacific ports.
Marilee Perkal, whose daughter and son-in-law are on board, said they had been told there are no signs of passengers with symptoms. She said her daughter recently sent a photo of her and her husband lounging by the pool.
As a precaution, her daughter told her, the ship has had no buffets since the start of its cruise. Guests are not even allowed to touch the salad dressing bottles. "That has been a comfort," she said.
On Wednesday, however, Hawaii announced no additional cruise ships would be allowed to dock. Passengers had not yet been informed of a new plan for disembarking, Perkal said.
Tom Hamburger, Julie Tate, Hannah Sampson and Jonathan O'Connell contributed to this report.