Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey
Speaker 1: brain Stuff, Lauren Bogle Bomb here Today we're kicking off
Speaker 1: mini series of health and safety topics surrounding the novel
Speaker 1: type of coronavirus identified in which causes what's therefore being
Speaker 1: called COVID nineteen. Because everything is a little less scary
Speaker 1: when you understand it better. So first up, let's talk
Speaker 1: about how long viruses can live on surfaces. Because between
Speaker 1: all those door handles, credit card keypads, and even our
Speaker 1: own cell phones, we interact with so many surfaces daily.
Speaker 1: I mean, even if you don't hand your phone over
Speaker 1: to everyone you meet, you probably put it down on, say,
Speaker 1: a table that other people have touched. And that's a
Speaker 1: fact of life. But some of what we colloquially call germs,
Speaker 1: that is viruses, bacteria, and other microbes that can cause
Speaker 1: infections in our bodies, some germs can survive on surfaces
Speaker 1: outside of our bodies long enough to spread from one
Speaker 1: person to another. There's unfortunately no hard and fast rule
Speaker 1: for how long viruses in general can live on surfaces.
Speaker 1: Part of the uncertainty is because viruses are diverse and
Speaker 1: have a variety of surface survival rates. The type of surface,
Speaker 1: and environmental temperature and humidity all come into play too,
Speaker 1: so which surfaces are safe to touch and how often
Speaker 1: do we need to disinfect them? But wait, let's back
Speaker 1: up a step. What are viruses and are they even
Speaker 1: alive in the first place. Things that we generally consider
Speaker 1: to be living have the more or less standalone ability
Speaker 1: to eat, grow, and reproduce. A single celled bacterium or fungi,
Speaker 1: or even a cell from your body can do all
Speaker 1: those things because they contain the genetic instructions to do so,
Speaker 1: plus the enzymes to carry out those instructions. But viruses don't.
Speaker 1: They have the genetic instructions the DNA or RNA, but
Speaker 1: they don't have the right enzymes to create the chemical
Speaker 1: reactions necessary for reproduction. Instead, viruses need a host cell,
Speaker 1: which can be bacteria, fungi, or a planter animal including
Speaker 1: a human. Virus will attack a host cell and release
Speaker 1: its genetic instructions, which hijack the host cells enzymes to
Speaker 1: make new viruses. That's good for the virus but generally
Speaker 1: bad for the host. Without a host cell, a virus
Speaker 1: can't survive long term. However, it does have a short
Speaker 1: window of time during which it can stay functional in
Speaker 1: hopes of infecting a new host and attaching to a
Speaker 1: host cell. Outside of a host, viruses can either stay
Speaker 1: intact and remain infectious, or they can degrade to the
Speaker 1: point that they're merely identifiable, which means that you'll still
Speaker 1: be able to identify them from their genetic material, but
Speaker 1: they won't be capable of seeking out and attacking host cells.
Speaker 1: At the point that a virus on a surface is
Speaker 1: only identifiable, it won't be able to cause harm. The
Speaker 1: length of time that viruses can remain infectious on surfaces
Speaker 1: varies greatly. There are baseline differences between viruses. For example, rhinoviruses,
Speaker 1: the viruses that are mostly responsible for the common cold,
Speaker 1: will last for less than an hour on surfaces. Others,
Speaker 1: such as the norovirus, which is a virus that can
Speaker 1: cause vomiting and diarrhea, can last for weeks, which is
Speaker 1: why noravirus can easily spread both through infected people and
Speaker 1: through contaminated foods and surfaces. There are several types of coronaviruses.
Speaker 1: Most cause mild symptoms and are responsible, along with rhinoviruses,
Speaker 1: for the common cold, but three types are known for
Speaker 1: causing more serious diseases mers, SARS and COVID nineteen, and
Speaker 1: because the coronavirus that causes COVID nineteen is novel, the
Speaker 1: research into how long it can last on surfaces is
Speaker 1: new and ongoing. A study published online on marcht by
Speaker 1: researchers at the National Institutes of Health, the US Centers
Speaker 1: for Disease Control and Prevention, and multiple universities compared the
Speaker 1: novel coronavirus with the coronavirus that causes severe acute respiratory
Speaker 1: syndrome or STARS. This is the most closely related human
Speaker 1: coronavirus to COVID nineteen and was responsible for the two
Speaker 1: thousand three epidemic. This study, which has not been peer
Speaker 1: reviewed as of this recording, found that the two viruses
Speaker 1: have similar viability in the environment, which is to say,
Speaker 1: not a whole whole lot something between rhinovirus and neurovirus.
Speaker 1: The study determined that novel coronavirus could remain infectious for
Speaker 1: up to three days on stainless steel and plastic surfaces,
Speaker 1: but survival on other surfaces was lower, just one day
Speaker 1: on cardboard and four hours on copper, and it was
Speaker 1: lowest of all in the air just up to three hours,
Speaker 1: but keep in mind that these numbers are the maximum
Speaker 1: for the viability of the virus. Viruses start to degrade
Speaker 1: pretty immediately when they're not in a host. The longer
Speaker 1: they're in the air or on a surface, exponentially fewer
Speaker 1: of them will remain infectious. And if your imman system
Speaker 1: is working okay, a lot of individual viruses need to
Speaker 1: get into your body, either via your mucous membranes like
Speaker 1: your eyes, nose, and mouth, or via cuts in your
Speaker 1: skin in order for you to get infected. That's why
Speaker 1: direct person to person contact is still the easiest way
Speaker 1: for coronavirus to spread, and why everyone's telling you to
Speaker 1: wash your hands before touching your face. It's also why
Speaker 1: we don't have more precise numbers for how long coronavirus,
Speaker 1: or any virus for that matter, no matter how long
Speaker 1: they've been studied, can last on surfaces. We spoke via
Speaker 1: email with Dr Alicia Kray, postdoctoral fellow in epidemiology at
Speaker 1: Emory University. She said, generally, survival of pathogens on famites,
Speaker 1: which are objects or materials likely to carry infection, is
Speaker 1: determined by inoculating a surface with a known quantity of
Speaker 1: virus and then sampling at various time intervals to determine
Speaker 1: the amount recovered. Scientists use this information to estimate a
Speaker 1: decay curve for the pathogen on the particular surface, which
Speaker 1: can be extrapolated to longer time in vals. The NIH
Speaker 1: and CDC team that studied surface variation for coronavirus is
Speaker 1: still researching. They're looking into coronavirus viability from snott versus
Speaker 1: flegm versus poop, as well as in varying environmental conditions.
Speaker 1: Because although viruses have differing baseline rates of survival on surfaces,
Speaker 1: additional factors affect their ability to endure outside of a host,
Speaker 1: like temperature, humidity, and properties of the surface itself, Cray said.
Speaker 1: In general, viruses survive longest at lower temperatures, higher humidity,
Speaker 1: and on non porous surfaces like stainless steel. However, some
Speaker 1: viruses do well at low humidity. There have been a
Speaker 1: lot of theories about whether coronavirus will lessen during warmer
Speaker 1: months because dry, cold air like in the winter tends
Speaker 1: to provide favorable conditions for flu transmission, but we simply
Speaker 1: don't know yet. Dr Anthony Fossey, Director of the National
Speaker 1: Institute of Allergy and Infectious Diseases explained during the March thirteen,
Speaker 1: twenty c in Facebook Global Coronavirus town Hall that when
Speaker 1: considering the viability of a virus on various substances, it's
Speaker 1: probably measured in a couple hours. While he recommends wiping
Speaker 1: down surfaces like door knobs and cell phone screens when
Speaker 1: you can, he cautioned against worrying about things like money
Speaker 1: and mail in the end. Despite the differences in viability
Speaker 1: on surfaces among pathogens, fomites, and contexts, the number one
Speaker 1: recommendation for preventing the spread of viruses is standard if
Speaker 1: you've touched a shared surface, wash your hands before you
Speaker 1: touch your face or any part of your body that
Speaker 1: might have a cut or other skin abrasion. The human
Speaker 1: skin is great at keeping out cold and flu viruses
Speaker 1: thanks to its pH and porous nature. They survive for
Speaker 1: only about twenty minutes on our hands. Today's episode was
Speaker 1: written by Carrie Whitney, PhD and produced by Tyler Clang.
Speaker 1: For more on this and lots of other topics, visit
Speaker 1: how stuff works dot com. Brain Stuff is production of
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