60% of cases on Aircraft carrier are asymptomatic

WASHINGTON (Reuters) - Sweeping testing of the entire crew of the coronavirus-stricken U.S. aircraft carrier Theodore Roosevelt may have revealed a clue about the pandemic: The majority of the positive cases so far are among sailors who are asymptomatic, officials say.

The possibility that the coronavirus spreads in a mostly stealthy mode among a population of largely young, healthy people showing no symptoms could have major implications for U.S. policy-makers, who are considering how and when to reopen the economy.

It also renews questions about the extent to which U.S. testing of just the people suspected of being infected is actually capturing the spread of the virus in the United States and around the world.

The Navy’s testing of the entire 4,800-member crew of the aircraft carrier - which is about 94% complete - was an extraordinary move in a headline-grabbing case that has already led to the firing of the carrier’s captain and the resignation of the Navy’s top civilian official.

Roughly 60 percent of the over 600 sailors who tested positive so far have not shown symptoms of COVID-19, the potentially lethal respiratory disease caused by the coronavirus, the Navy says. The service did not speculate about how many might later develop symptoms or remain asymptomatic.

“With regard to COVID-19, we’re learning that stealth in the form of asymptomatic transmission is this adversary’s secret power,” said Rear Admiral Bruce Gillingham, surgeon general of the Navy.

The figure is higher than the 25% to 50% range offered on April 5 by Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and a member of President Donald Trump’s coronavirus task force.

‘DISCONCERTING’ DATA FOR PENTAGON

Defense Secretary Mark Esper, speaking in a television interview on Thursday, said the number of asymptomatic cases from the carrier was “disconcerting.”

“It has revealed a new dynamic of this virus: that it can be carried by normal, healthy people who have no idea whatsoever that they are carrying it,” Esper told NBC’s “Today” morning show.

Such data present challenges to the Pentagon, which is deployed around the world, sometimes in confined environments like submarines, ships and aircraft.

Testing the entire military is not yet feasible, given still-limited testing capacity, officials say, and detecting enough cases without tests is impossible if most cases are asymptomatic.

The U.S. coronavirus death toll - the highest in the world - surged past 31,000 on Thursday after doubling in a week.

It also claimed the life of a sailor from the Theodore Roosevelt this week. Five other members of the crew are hospitalized.

NUMBERS UNKNOWN

Still, the case of the Theodore Roosevelt offers a case study for researchers about how the virus spreads asymptomatically in a confined environment among mostly younger adults.

That cohort has been somewhat underrepresented in the epidemiological data so far, said William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center.

“The findings are of enormous interest because the proportion of people who are asymptomatic is just simply not known,” Schaffner said, when asked about the Navy’s data.

Vice Admiral Phillip Sawyer, a deputy chief of naval operations at the center of the Navy’s coronavirus response efforts, presented the 60% figure in a call with a small group of reporters on Wednesday.

But he declined to speculate about the implications.

https://www.reuters.com/article/us-health-coronavirus-usa-military-sympt-idUSKCN21Y2GB

Goffman co-authored a new study that tested more than 200 pregnant women admitted for delivery in two New York City hospitals for coronavirus whether they showed symptoms or not. Thirty-three women tested positive, but 29 of them showed no symptoms, according to the results published this week in the New England Journal of Medicine.

https://www.yahoo.com/news/study-nearly-pregnant-women-had-123622151.html

We went from almost no one to a huge influx of COVID-positive people, with the really interesting twist that most of them were asymptomatic, they did not have symptoms,” Jim O’Connell, president of Boston Health Care for the Homeless, said in a recent interview with Boston.com.

https://www.boston.com/news/local-news/2020/04/16/boston-homeless-care-covid-19-update

AI wrote: I think that more and more the data is showing that potentially a very large segment of the population already infected are asymptomatic and that another equally as large if not larger segment of the population only have mild symptoms. The actual CFR is going to be only slightly higher or equal to a bad flu year I'm betting once all of those actually infected with the virus are accounted for.

It's an interesting idea but it doesn't sit with any of the data already published. If you're suggesting that 60% of people are asymptomatic but positive and therefore the virus has already spread widely in the population, then 60% of all tests where ever they are conducted should return a positive result and this is not what we're seeing anywhere, the US included.

KiwiMum wrote: AI wrote: I think that more and more the data is showing that potentially a very large segment of the population already infected are asymptomatic and that another equally as large if not larger segment of the population only have mild symptoms. The actual CFR is going to be only slightly higher or equal to a bad flu year I'm betting once all of those actually infected with the virus are accounted for. It's an interesting idea but it doesn't sit with any of the data already published. If you're suggesting that 60% of people are asymptomatic but positive and therefore the virus has already spread widely in the population, then 60% of all tests where ever they are conducted should return a positive result and this is not what we're seeing anywhere, the US included.

"During an April 5 White House Coronavirus Task Force media briefing, Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases put the number of asymptomatic cases "somewhere between 25 and 50%." 

Beijing: China for the first time publicized a breakdown of people testing positive for the novel coronavirus without outward signs of being sick, revealing that those among them who remain symptom-free throughout infection are in the majority.

Among 6,764 people who tested positive for infection without showing symptoms, only one fifth of them — 1,297 — have so far developed symptoms and been re-classified as confirmed cases, China’s National Health Commission spokesman Mi Feng said at a briefing in Beijing Wednesday.

However, a recent WHO report states that among infected people, 80% are asymptomatic or have mild symptoms. The exact split between mild and no symptoms is unclear, however, as is the basis on which the asymptomatic cases were identified.

Immunologist Sergio Romagnani concluded that this shows that anywhere from 50% to 75% of infected cases showed no symptoms, while still being able to spread the virus freely. Another study in Iceland based on a widespread testing effort also supports the view that at least half the positives are asymptomatic. In stark contrast, most testing taking place in other parts of the world today is confined to people who have symptoms suggestive of coronavirus infection and go into hospital.The current study also cites research from Vo, an isolated village of about 3,000 in Italy. Blanket testing was followed by the isolation of symptomatic as well as asymptomatic positives. This brought down the rate of positives by about 90% over ten days, from 3% of the population to 1%.

Not one study but many, FluMom.

I think I can hazard a guess at one factor of the many, temperature.  There is a culture of being the 'tough guy' (even the women) in the forces.  They are then less likely to take a tylenol if they habe 'a bit of a temperature'.  This bug does not like temperatures over 104*C.  So the: 'Only wimps take pain meds' attitude can really pay off.  General good health, diet and reasonably low age groups all add up to less serious problems.  

But that is the tip of yet another iceberg, there is still loads we do not know about this bug.

AI wrote: KiwiMum wrote: AI wrote: I think that more and more the data is showing that potentially a very large segment of the population already infected are asymptomatic and that another equally as large if not larger segment of the population only have mild symptoms. The actual CFR is going to be only slightly higher or equal to a bad flu year I'm betting once all of those actually infected with the virus are accounted for. It's an interesting idea but it doesn't sit with any of the data already published. If you're suggesting that 60% of people are asymptomatic but positive and therefore the virus has already spread widely in the population, then 60% of all tests where ever they are conducted should return a positive result and this is not what we're seeing anywhere, the US included. And what you are stating assumes a 100% infection rate of the entire population. That is not what I stated or the articles suggested. They stated that a very large percentage of positive cases tested are asymptomatic. It doesn't take a rocket surgeon to make the connection that there are more positive asymptomatic cases in the infected population that are untested. And studies are starting to show that.

No, what I'm saying is that if there was a great many asymptomatic cases in any population, and therefore the spread was much wider than was previously thought, then this would show up in testing, and it's not. At the moment most countries are testing thousands of people and only showing up a small percentage as positive, so where are the asymptomatic cases? If they have it, they'll give a positive test result. I'm deducing that by looking at the statistics that are being published. The numbers don't back up your assertions.

In my country they've just started doing random tests on people at supermarkets to see if they can find any asymptomatic carriers. So far they haven't found any. But they've only just started it, and it will be interesting to see if they do. They've picked supermarkets and supermarket workers particularly because they come into contact with so many people each day and would be the ideal silent spreaders in the community.

Another possibility is a different strain.

We've only had 1400 cases here and under lock down, we now have 600 active cases. We've had 11 deaths and we have 15 people in hospital, 2 in critical condition. We don't have the kind of widespread cases you have in the UK or in the USA. We've still got another week of lockdown to go. We had 8 new cases yesterday and are doing on average 2600 tests a day. Hopefully we'll be virus free soon.