Skip to Main Content

This weekend, as it became clearer and clearer that Covid-19 has been spreading stealthily through the Pacific Northwest, the task facing health officials has become more and more monumental. To try to stop the virus’ transmission and restrain the outbreak, they need to identify every single person with whom patients have come into contact, isolate those at risk of harboring the illness, and monitor the entire network of people for symptoms.

That’s hard even if you know how each patient became infected. If you don’t, it can be downright herculean. The fact that the pathogen is passing through people without making them sick enough to seek care means that they may have unwittingly transmitted it for weeks before it came to the attention of authorities. Once a case is discovered, epidemiologists still need to figure out whom the patient might have exposed. But they also need to look in the other direction, too, to figure out by what unseen route the virus reached that person in the first place.


“The question is, what is their source of exposure?” said Laurence Burnsed, state epidemiologist for Oklahoma’s health department. “Who are we missing?”

Answering such questions requires state and county health agencies — overworked as they already are — to ramp up their efforts as fast as possible.

“Speed is critical. Speed is absolutely critical. Every country that is receiving their first cases needs to act robustly and aggressively. … Look for this virus,” said Maria Van Kerkhove, head of the emerging diseases and zoonoses unit for the World Health Organization’s global infectious hazard preparedness team, in an interview with STAT.


Controlling the outbreak means getting ahead of the virus — and that’s no mean feat in a situation shifting so rapidly.

On Friday night, there were reports of four people — two in California, one in Oregon, and one in Washington State — who’d tested positive for the virus but had neither a known history of traveling outside the U.S. nor any identified contact with previously diagnosed patients. By Saturday afternoon, officials reported an outbreak of the virus in a long-term care facility outside of Seattle as well as the first death in the U.S. due to the illness — but it wasn’t clear whether those two events were related.

“That’s the kind of thing that we’re trying to answer now,” said Jeffrey Duchin, health officer for public health for Seattle and King County in a Saturday press briefing. “We’re doing an investigation as we speak to try and understand all the potential exposures that that patient may have had and if there’s any potential commonalities … but at this point we don’t have links.”

By Saturday night virologists had sequenced samples from one of the mysteriously acquired Covid-19 cases in Washington State, and found that the pathogen looked like a descendent of the virus swabbed from the first reported case in the U.S., identified way back on January 16. But there was no known contact between the two patients.

“There are some enormous implications here,” tweeted Trevor Bedford, a researcher at Fred Hutchinson Cancer Research Center in Seattle, who studies how viruses evolve and spread. “This strongly suggests there has been cryptic transmission in Washington State for the past 6 weeks.”

But genetic sequencing data come from already diagnosed cases. That can’t help you find people whose infections have gone undetected.

For that, you need the old-fashioned detective work of contact tracing.

It begins with an in-depth interview. An official sits down with a patient, and together, they reconstruct exactly where that person has been and with whom, day by day, hour by hour, for the entire window of potential contagion. The conversation often lasts hours. “That would be having the case pull out their personal calendar, going through their phone,” Burnsed said. “They might even have to go through their social media feed to see where they were tagged and what they did, to kind of jog their memory.”

The officials try to identify every single person who might have been unwittingly exposed to the pathogen. They start with family members and close friends — but then, as Burnsed put it, “the next level is identifying all of the contacts in shared airspaces.” Did you go to restaurants? What time were you there? Did you go to work or school? Did you take your child to daycare? Did you go see a doctor?

It’s already enough work to try to identify everyone who might have been at a hospital at the same time as that person — pulling rosters of on-shift workers, asking for appointment times of other patients, trying to figure out if they were there with family members. Other public spaces can be harder, because there are less meticulous records of who was where when.

Once officials have reached everyone they can reach, they still need to monitor them, and if they are at risk of spreading the illness, make sure they isolate themselves. Even for a handful of cases, it’s an unwieldy operation: When Oklahoma identified four measles diagnoses last year, the health department had to assess 300 individuals, Burnsed said.

While Covid-19 is less contagious than measles, the effort required for contact tracing investigations last year illuminates the sort of scramble Washington state officials are facing now. In a single nursing facility alone, some 50 people —including both staff and residents — have symptoms and are undergoing testing for the virus, and those aren’t the only potential cases.

The sheer number of people to reach won’t be the only issue. “Challenges in any large outbreak involve fully identifying all contacts including those that may have been exposed in a more public setting (and who are not known by name), insufficient or incorrect contact information given that hinders finding contacts, and lack of compliance by identified contacts,” Sharon Watkins, Pennsylvania’s state epidemiologist, wrote in an email to STAT.

That issue can be especially prevalent for vulnerable groups, such a undocumented immigrants, who worry that identifying themselves to health authorities might make their situations even more precarious.

In American Samoa, for instance, during the measles outbreak that began late in 2019, some people from the nearby Independent State of Samoa, as well from Tonga, Fiji, the Philippines, China, and Korea, were worried that participating in contact investigations might jeopardize their immigration status .

“Some of these population groups are close knit and will not easily reveal who in their community are or were sick with measles,” explained American Samoa Health Department Epidemiologist Aifili John Tufa, in a text message. “They are afraid that if they tell our team they may be ‘incriminating’ their own.”

Yet, to the WHO’s Van Kerkhove, in spite of these challenges, it’s imperative that public health officials in the US and around the world race to track and control the virus’ spread. “What worries me the most is people feeling like there’s nothing that they can do and they just have to give up and surrender to this virus … and we just have to let the wave pass through,” she said.

She is hopeful that by identifying and isolating potential Covid-19 patients, health departments can restrain the outbreak. “Every single country has the possibility to contain [transmission],” she said. “I’m not suggesting that this is easy. … But it can be controlled.”

Helen Branswell contributed reporting.

  • Ask the phone companies to help with the contact tracing. Cell-phone location records can trace a persons movements, very quickly in most cases. Other cellphones that were in the same location could be notified, even without knowing the peoples names.

  • The only comforting thought is that it might take out Trump and Pence and a lot of other old Republican science deniers and then maybe we can save the planet for the survivors and the human race might escape extinction after all. Rush Limbo and the rest can’t die fast enough. This virus is the earths immune system stepping up it’s response to the planet’s most deadly threat, old, stupid, humans. Good luck humanity.

    • Also to note. President Trump did step and is still stepping up as a leader. He had stopped all international flights flying out of China within a few days from hearing about this virus. And then banned international flights from other countries that have been infected. He also made sure to quickly worked to put up the Wall at our boarders, so that people couldn’t just flood our country with whatever disease and virus they may have.
      So really if this was your typical demoncrat President they wouldn’t have made such a bold move to stop flights especially from china and our boarders would’ve been flooded with people who have the virus as well as other diseases, which would’ve overwhelmed our hospitals, schools etc. Causeing a China like scenario. But Thank God we have a strong and smart leader in charge. I Thank President Trump for all he and his team are doing. And we all have to do our part cause it’s not up to just one man. We as Humanity need to come together and work together to rid this virus the best that we can. God Bless

  • In US as by Friday we had only tested 479 people! And as doctors announce, they DO NOT have tests to test people – NY, the supervisor of one of the most important hospitals says he has NO KITS to test people…. ( CNBC,

    WHY we do not have tests? WHY we didn’t accept test kits from WHO as other countries?

    6 deaths in Washington state today indicate 300 cases, and they have confirmed only 18 infections.

    In Illinois, the school of a kid with infected parent was told to stay home until 24 hours after he has fever…

    Who is in control? What are the conditions, the rules, the guidelines????

    SOMEONE needs to take responsibility and lead this situation.

    VP. Pence just came out to say that the risk is LOW! No it is not LOW anymore and if the administration cannot understand this, have someone to explain it to them, as soon as possible.

    The virus goes undetected in many states for weeks. Even if there was only one infection 14 days ago (in the 11 states currently in trouble), with a doubling time of 3 days we should have on average 2^5 = 32 in each of those states (352) AT LEAST!!!!!
    With Washington state leading with a prediction of at LEAST 300 cases.

    This is a low estimate. In 9 days, this will be 2500+ if we do not take immediate measures.

    Our numbers 102 infections and 6 deaths ( all in WA with 18 infections) are worst than Iran’s data, showing what that in WA the virus has 33% death rate????

    The University hospitals need to start testing, now that FDA allowed this. Not those who come from other countries, but those who have symptoms, at least in the states that have infections that are not related to contact or travel.

    We need to take charge of this otherwise by next week, we will be in thousands, as the infections double every 2 days if there is no control.

    And finally close the schools and the universities as Japan did for a month, online classes are possible, because we already see that the younger population may be spreading the virus while asymptomatic. This is crucial, especially to give us time to get test kits to every hospital.

    We cannot delay anymore.

  • I still think the CDC should re investigate the longevity of the virus on surfaces…
    They’re focused on people to people contact but neglect where and what these people were doing i.e. Handling a fueling pump at a self-serve petrol/gas station, ordering from a laminated menu given at Restaurant’s by the waiter/waitress, to using the drive-up bank ATM pressing terminal buttons,to doing laundry at a public coin-operated laundry mat, to using their bank card at food stores or at Walmart waiting at the crowded checkout line, were one by one, people sliding their card and pushing the electronic register buttons with their dirty smelly fingers…that hundreds of other people had pushed prior to their turn, with their dirty, grimy picking-in-their-moist-nose fingers. I think CDC will find that this type of Covid-19 coronavirus lives on these surfaces longer than they had realized and should be swiped and tested a.s.a.p.!

    • Not to mention, class desks and computers, pondiums, whiteboards in University classrooms, computer labs and libraries.
      In addition, the virus is concentrated in feces and it spreads in air with every use of the toilet. Note that Universities and schools do NOT have toilet covers, so everyone who uses the toilets is not protected by any means.

      We do not have the expectation from anyone to disinfect the toilets nor the classrooms every hour in a university or a school but how can students, faculty and staff can be protected.

      How can you stay away from those who are sick, when you need to ask and answer questions? When attendance is mandatory? When exams cannot be skipped? Nor lectures? When active learning and group work is essential?

      Can somebody understand than in the schools and the Universities we do not have only students but older adults as well???

      Doesn’t anyone understand that

  • When Trump suggest building the wall, I was thinking that would come very handy if you have a epidemic from the south of the border. It will prevent mass migration from the south.

    I never thought a pandemic will come so soon.

  • The “speed” would have been a good idea at the beginning of the outbreak. it is kind of silly now, and there are very few test kits available. It is likely already spreading among health workers and others who come in contact with the public. Putting another spin on the nonsense, helps no one, when most people cannot even afford the test or a trip to a doctor. There is also severe distrust of the medical community and the government.

    • I no don’t bother reading any comment from WHO now. It is a waste of time. They fail in their responsibility by their complacency. They are even against closing the border.

      The Washington case was traceable to the case # 1 in Washington. That POS does not deserved to be saved, please excuse me for saying this.

      He knows he comes from Wuhan where the virus was going around. He knows it is deadly. He should have taken precautions all the time not to infect anyone.

      I caught a flu from someone in the plane while I was wearing a surgical mask. Two irresponsible people had a flu and cough without wearing a mask. I suffered acute respiratory infection for weeks. But I made sure the virus stop with me. I don’t go out except to buy food and go to doctor. I was always wearing a mask. When I enter the grocery or clinic, I go first to restroom and wash my hand so I do not spread it around with my maybe contaminated hand. I was not even coughing but I wore a mask to make sure the virus does not infect anyone else.

      But it seems in life some people don’t care, you see people coughing without even making effort to cover their mouth. I get it that mask is not available, but at least cough on a tissue and throw it away instead of just coughing with open mouth without any care for anyone else.

      This irresponsible people are what made reason flu spread around and kill people year after year. They never thought that someone will die because of their irresponsible act.

      If you harm somebody, it is a criminal act. Shouldn’t knowingly spreading your virus around, knowing it can kill someone with compromise immune system also be considered a criminal act. Tens of thousand of people die each year from flu. Something that can be prevented if someone is considerate enough to take extra action not to spread their virus around.

      This patient #1 had cause the dead of someone because of his irresponsibility. He should have worn a mask from the time he board the plane and practice proper hygiene so as not to pass on to other people.

    • I agree, there is great mistrust of the government, the Chinese government. Trump shut down travel from China which is why there are so few cases in the US, you’re undoubtedly a Bernie Bro

    • Eli, as the article states, “The fact that the pathogen is passing through people without making them sick enough to seek care means that they may have unwittingly transmitted it for weeks before it came to the attention of authorities.” Therefore, it’s uncalled for to blame people for spreading it, especially at a time when little was known about it. Also, there are medical reasons for not closing borders. The threat of closing borders leads countries to suppress news about cases, and closed borders prevent countries from getting the resources and specialists they need to deal with the virus.

      None of this is perfect, and it’s all very frustrating. But hatred of people who’ve been exposed to virus and mistrust of WHO are only going to make things worse.

      I thank you for being responsible when you were sick. I hope that more people will follow your example.

    • Branwen, I am not blaming the people who have no symptoms when in concern flu or coronavirus, unless of course they come from heavily infested countries. Then they should take precautions as they can be carrier.

      Patients no 1. knows he comes from a place with an epidemic that going on, that means he can be a carrier. He should have taken the precautions.

      But from what I read before, he did self quarantine himself. So maybe he did not wear mask went he went out to buy food or seek treatment. This needs to be investigated for informative purposes to correct the gap.

      The patient in California that comes from Wuhan self quarantine herself.

      Hate is a very strong emotion. I don’t think it applies to my logical statement.

    • The virus cannot stop by itself. We need to stop it. The doubling time if we do not act is 2.5 days, by now we have at least 1000 cases based on deaths and timing. This means that if they do not act with “speed” now, we can easily have 4000 infections in 10 days.

      The tests should be free, they are not to protect who has it but the rest of the population.

      Please do the calculations, there is need for urgency, this virus goes nowhere if we do not act. The only thing that can happen is to mutate and kill more.

      It is not the time to find out who is responsible for where we are, it is the time to fight it with any available way.

    • Branwen, a lot of people, including me, trust the medical community. COVID-19 doesn’t just spread through healthcare workers, it spreads through regular people too. Eli, a mask doesn’t do anything, viruses are too small. Scott, will you please stop looking at Trump’s twitter account and read what the CDC or WHO has said, or I dunno someone who actually knows what their talking about in regards to COVID-19.

  • Hysteria, that’s what we’re dealing with in this so called pandemic. For kerist sakes 20,000 people have died from the common flu in this country since Nov.
    Hey Adam, the USA ain’t China, try Wuhanizing here and you’ll have a civil war on your hands. Unlike stupid Europe, Trump has the situation under control, don’t go getting your panties all bunched up.

    • Scott, please stop your nonsense of comparing this virus with flu. So many are unknown with this virus, we are not even sure if it will go away in warm weather. If it does not go away in warm weather, then there is no reset point and the tree of infected people will just exponentially increase.

      Trump had lose control of the situation, due to colossal blunder of CDC and HHS. The test kit was defective and the CDC Atlanta lab that manufacture the kit failed the inspection of the FDA.

      The CDC was dishonest and misleading is saying there was an error in the manufacturer, so that people will think it was a third party. But they are the manufacturer of the kit.

      Google this “Scoop: Lab for coronavirus test kits may have been contaminated”

      Unfortunely, we will a high price for CDC ineptitude.

    • To Scott.
      I don’t know if you can qualify Europe stupid just because they couldn’t stop the virus to spread around. The virus has also spread around in the US for weeks but nobody knows the extent of the phenomenon since US didn’t measure it. So wait some weeks before saying the US has it under control. No comment on Trump, he is so stupid and rude.

    • I will not agree with you that Trump is stupid. He has other faults. Don’t let your hate blind you. He has faults but at least he keeps some of his promises during the election.

      He put the travel ban despite being condemn by some part of society. But I do disagree with his saying that the epidemic is under control and things are fine. The CDC feed him misinformation to cover up their lack of testing. They even miscommunicate that the first fatality is a female. I would like to see some people in CDC fired.

      I would say Nancy Pelosi and Schumer are selfish to the core. We have a pandemic in the making in Jan, but the all they focused and care about is the impeachment. That was one whole month wasted when we could have focused our attention to coronavirus and a solution.

      I am not a Republican, but I would like to see the Democratic party lose control of both House and Senate this election. They are not the right party to guide us thru this pandemic seeing how little they care about it or the general population.

      They need to stop appearing they care for the people. Jan was the time they could have taken the high road put and aside the impeachment because of the pandemic in the making in China. But no, they have to stick to their own selfish interest and go on with the impeachment. Maybe their will be less eventful death if they do that.

      Even now all they do is attack instead of coming together to come up with a solution.

      For three whole years, all I hear is them going against Trump against everything.
      No matter whether it is beneficial to the country or not, they just have to go against Trump. They put the party interest before the country. I am not saying they are always bad, but the last two years was plain bad under Pelosi, AOC, Kamila Harris and so on. It was all criticism with no good counter solutions.

      That is why Kamila Harris is the first to bow out. She had nothing to offer except history of going against Trump. What a shallow politician.

      I do not care of a party that care more for their party of their party than the people.

    • I love how you say, “you’ll have a civil war on your hands.” What kind of animal says that in 2020. 88 cases in the US and two deaths and all i see is Trump telling everyone to “calm down” when China is telling its doctors and investigators that they can do better. I am all for trump but you saying that that “stupid europe” doesn’t have it under control well they have fewer cases then we do atm. and as for china, its not completely their fault this even started. Think about it as them being a 3rd world country. They have less sanitation in more crowded areas like markets, which is where they think the outbreak started. If this goes pandemic, you are gonna hope and pray these other countries don’t see your mean nieve post. they have incredible doctors and virologists.

      Count your blessings Scott. We are blessed as a country to have less cases and deaths then a lot of countries, but that could change faster then we think. We are gonna have different opinions but we are americans and thus we have to stick together.

    • Scott, Read about Australia changing laws, UK, Europe, this is not a matter of who has it under control and who is responsible.

      We are in a war with the virus, and we need to be together, work together and understand the situation before it spreads everywhere.

      6 deaths in WA, means 300 infections at least. It is not under control, until Friday hospitals were not able to test and they were not testing.

      Please, do not stay on the numbers, the prediction is that we will have millions of deaths if we do not move fast. You are comparing a shotgun with a tank here. The only difference is that the tank hasn’t start firing yet.

    • “Trump has it under control” Famous last words. A man, who knows nothing, says a man who knows nothing, has everything under control. Stupidity causes harm to the stupid one and everybody connected to them. Don’t spread stupidity, it too is contagious.

    • First of all, let’s not bring politics into this, the only thing we need to focus on is following the advice of the CDC and WHO to help contain this virus. Blaming it on others is not going to help, neither is listening to those who have aren’t knowledgeable about disease control and prevention. COVID-19 is a big deal, it spreads way more rapidly than the flu, and is pretty unknown. Let’s stop be complaining about the CDC or WHO, they are doing their best, so is China and Europe.

  • Good article. Singapore used police detectives and quarantine orders to make this work. South Korea publishes records of exact locations and times. Question is, do you trust Washington and and California State health authorities, even with the help of the CDC? Would I stake the country’s near-term future on these authorities. Answer, clear, “No,” which might explain why we see large numbers of National Guard troops on the move in Oregon.

    At some point very soon, going to have to create a cordon sanitaire where certain areas are Wuhanized.

    • There is zero risk that the US will ever become Iran, because: A) we have no caviar, B) we are a secular, democratic republic 3) we do not condone wearing turbans 4) we make lousy Persian rugs €) we use the present tense to describe current movement; i.e. I Run, not Iran. Fear not!

    • Informing and talking and sharing information and knowledge at this point is a responsibility of everyone.

      We will find out who is responsible at a later day, the problem is that a lot of people have been kept in the dark, and do not understand the numbers, nor the trends. They will stay oblivious until will get to thousands of infections, and although it seems that this will be next week, this will already be late.

      Please continue talking, explaining, and spreading the information, as you do. You are correct, US is getting close to been banned as a destination by this coming week if there is no radical action.

Comments are closed.