Who is most likely to be an asymptomatic COVID-19 carrier?

Is this a case of Typhoid Mary: The Sequel?

young woman walking the streets during the day

Throughout history it has not been uncommon for people to wander around with infections and no symptoms of being sick.

In the early 1900s, Typhoid Mary spread typhoid fever to other people without having any symptoms herself.

And it seems we may have a few like her roaming around right now, if a small Chinese study is anything to go by.

The study from Wuhan University found that people with COVID-19 who don’t show symptoms tend to be younger and are more likely to be women, and asymptomatic people seem to experience less damage to their immune systems than symptomatic patients.

When comparing asymptomatic COVID-19 positive patients with patients who displayed symptoms, researchers found that asymptomatic people still shed the virus, but for a shorter period of time.

The median age of asymptomatic patients was 37, with two in three being women.

No one really knows how widespread asymptomatic COVID-19 infection cases are, but anecdotal evidence suggests that this may be a reason the virus has been so ‘successful’.

“Although patients who were asymptomatic experienced less harm to themselves, they may have been unaware of their disease and therefore not isolated themselves or sought treatment, or they may have been overlooked by healthcare workers and thus unknowingly transmitted the virus to others,” it read.

“Fortunately, patients with asymptomatic SARS-CoV-2 infection have a shorter duration of viral shedding from nasopharyngeal swabs and lower risk of a recurring positive test result of SARS-CoV-2 from nasopharyngeal swabs, which can provide a reference for improving the prevention and control strategies for patients who are asymptomatic.”

Asymptomatic cases are far more common than researchers are comfortable with, too.

In a nursing home in Washington, many residents became infected. Of these, 23 tested positive, 10 were already sick, 10 more eventually developed symptoms, but three people who tested positive never came down with the illness.

Of the 397 people staying at a homeless shelter in Boston who were tested, 36 per cent were positive for COVID-19 but not one of them complained of any symptoms.

Of all the Japanese citizens evacuated from Wuhan and subsequently tested, 30 per cent of those infected were asymptomatic.

And an Italian study found that 43 per cent of those who tested positive for COVID-19 showed no symptoms.

Researchers are still unable to tell the difference between how potentially contagious people with or without symptoms are, but they estimate that anywhere from 10 to 40 per cent of the total number of infected people around the world may not experience symptoms.

COVID-19 has infected more than 5.5 million people and killed more than 350,000 worldwide, but the infection rate could be much higher, with many of those infected being ‘silent carriers’ who show no or very mild symptoms.

Even if someone is not coughing or sneezing, infected droplets can spray from normal exhalations. A regular breath may spread the virus. Research published in the Proceedings of the National Academy of Sciences (PNAS) suggests that talking launches thousands of tiny infected droplets that remain suspended in the air for up to 14 minutes, which could explain “how people with mild or no symptoms may infect others in close quarters such as offices, nursing homes, cruise ships and other confined spaces”.

Surfaces, such as lift or traffic light buttons, doorknobs or shopping trolleys or baskets can also be contaminated with the coronavirus by an infected person’s touch.

The government’s COVIDSafe app is also not helpful in the case of asymptomatic users.

It goes without saying that every day brings another challenge in controlling or even knowing about COVID-19, and that much more data is needed on asymptomatic transmission.

Asymptomatic SARS-CoV-2 infection may be complicating efforts to get the pandemic under control and find a vaccine.

The message in the meantime: stay safe and don’t let your guard down even when no-one’s around.

Do you think you may have had COVID-19 and not known about it?

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    To make a comment, please register or login
    29th May 2020
    I wish there was a test to see if we have had it. It would save a lot of angst and enable us to go back to our daily lives as usual.
    In the meantime, let the economy roll on and anyone who is at high risk should protect themselves or be protected by their carers.
    29th May 2020
    There is a test for Covid-19 antibodies and that is how they know many people have had it but didn't know.
    29th May 2020
    The antibody tests are not as accurate...only 75 per cent...they are not very sensitive or specific for coronavirus....they also pick up whether you had the common cold...so false positive or false negative results are common.
    The Thinker
    29th May 2020
    Tests can detect nothing when health authorities have no knowledge of what they are dealing with.

    The recent 30 year old Australian male that tested as positive but later he tested as negative. He had no contact with anyone maybe he had caught the virus from a female kangaroo. He had other illnesses that were ignored and not treated. His death certificate states Coronavirus to me that is false considering he tested as negative.

    China blames women for being carriers, I blame China's mindset that's why it has a shortage of young females and kidnaps them from neighboring countries.

    Human overpopulation is the pandemic, not COVID19.
    29th May 2020
    I know people who work in the medical profession. They are only swabbing people who meet the criteria - those they are almost sure they may have the virus. There may even be people that have come into contact with the virus that don't actually get sick from it at all but pass it on. (classed as carriers. It can happen with other viruses, diseases etc). One of the huge problems is that most people have it for approx. 14 days before they begin to show any symptoms at all. It used to happen with other diseases prior to the introduction of vaccines.
    29th May 2020
    A friend of mine who works in a doctors surgery has all the symptoms of Covid-19 but has tested negative 3 times. Another fellow I know tested positive 4 times and never had a symptom. I'm starting to question the reliability of the tests.
    The Thinker
    29th May 2020
    How can there be a test for something no one knows what they are dealing with?
    29th May 2020
    If true then my blind grandmother would ask, why dont ALL wear a face mask??? Wht do the government not demand such?
    4th Jun 2020
    29th May 2020
    I wouldn't trust anything that came out of that city or university.
    29th May 2020
    This is not surprising, history tells us that every time there has been a world-wide contagion some people are not outwardly affected. Take the Spanish Flu of the early 20th century, millions died but millions were not affected. Similarly the Bubonic Plague of the 14th, 16th, 17th and 18th centuries killed millions, in the 14th century about one third of the population of England died from the plague, and death was almost certain once the disease was contracted. The mystery is why did those unaffected remain unaffected. Do some people, for some unexplained reason, have a better immune system than others. Then there was Mary Mallon, aka Typhoid Mary, who was a cook and an asymptomatic carrier of Typhoid. Why?
    29th May 2020
    Many people get the flu every flu season and have no symptoms too.
    The Thinker
    29th May 2020
    I wonder if the pandemic was part of a Bilderberg meeting plan to eliminate the overpopulation problem. Bill Gates discussed it back in 2015.

    4th Jun 2020
    Certainly strange like I have been in very close contact within the family with chicken pox, shingles, mouth cold sores and have never become sick with them!
    Even parasites like mozzies, bed mites and head lice don't seem to like my blood yet scabies and fleas can give me hell!
    Life experience
    29th May 2020
    All frontline workers are being asked to be tested from now until 15th June. Police, supermarket workers , nurses, Dr’s etc. I hope many do as this will give us a better indication of community spread and amount of asymptomatic people in community. We need as many as possible to do this.
    29th May 2020
    Yes and bloody Pauline Hanson wants to reopen the borders, because money and profit is more important than peoples lives. The elderly and those with underlying conditions, heart, diabetes, respitry etc etc , covid19 is a DEATH sentence. Bloody Pauline, you know I once repected her.
    The Thinker
    29th May 2020
    Let's hope she catches it.
    29th May 2020
    Well protect those people.Dont keep everyone else from getting back to a normal life
    29th May 2020
    Covid 19 Testing.Throw shit at a wall and see what sticks Make your decisions from that.
    31st May 2020
    Another fear mongering article by YLC's. We have already discussed all of this in other topics and threads, there is some evidence that tests can be inaccurate, and who makes the tests China?
    31st May 2020
    Fact check: tests are made in Australia, Germany, Denmark, Spain, Canada, Korea and the USA.
    While tests are also manufactured in different parts of China, many of those are sponsored by Australia.
    31st May 2020
    The Thinker: there is no place in these pages for plainly nasty comments and wishing Vivid on anybody is really nasty.

    And the real reason why there is a shortage of females in China is because of its one child policy made to curb population growth. The Chinese always want a son because in their culture the son takes care of them in their old age. Sadly some girl babies were killed at birth and where gender testing of unborn babies was possible , and affordable, girls were aborted.

    Eddy the bubonic plague was spread by fleas carried around by rats. That plague was caused by bacteria, and in today's world is cured by antibiotics unlike Vivid 19 which is a virus and will therefore not respond to antibiotics.
    People who were lucky enough to survive had good immune systems which were genetically altered by the bacteria, so that their children had a resistance to it.
    31st May 2020
    Sorry my computer decided to change Covid to vivid!
    31st May 2020
    Retiring Well , if you got the flu - real flu as opposed to the common cold which too many people call flu - you would know about it all right.
    31st May 2020
    "Do you think you may have had COVID-19 and not known about it?"

    Now, that's a really dumb question! If you didn't know about it, how could you possibly think you might have had it? In order to THINK you had it, you would have to have either had a positive test or had some symptoms. In either case, you would know about it.
    1st Jun 2020
    Just a minor question about this article:
    "Of all the Japanese citizens evacuated from Wuhan and subsequently tested, 30 per cent of those infected were asymptomatic."
    What were Japanese people doing in Wuhan, which is in China?
    1st Jun 2020
    They were probably working there just as Australians work all over the world . At last count (2011)
    there were 113,000 of us in UK alone. If you Google a bit you will find that there were 878, 000 Chinese in Japan in 2017and so on ...

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