# The Flu - "I'm not contagious anymore." **URL:** \ **Category:** Factual Questions\ **Created:** [February 18, 2018, 6:17pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060 "2018-02-18T18:17:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![SanDiegoTim](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@SanDiegoTim](https://boards.straightdope.com/u/SanDiegoTim)\ **Post date:** [February 18, 2018, 6:17pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/1 "2018-02-18T18:17:51Z")
Assuming one can get to this point, what exactly makes someone non-cantageous? How does one really know they’ve gotten to this point? ---
**Author:** ![LH75](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lh75/32/4438_2.png) [@LH75](https://boards.straightdope.com/u/LH75)\ **Post date:** [February 18, 2018, 7:01pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/2 "2018-02-18T19:01:20Z")
I certainly would like this answer too. I got my flu shot, as usual, and for the past couple of weeks I have had a horrible case of the flu. I have been avoiding getting closer than a few feet to anyone hoping to avoid spreading it. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [February 18, 2018, 7:13pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/3 "2018-02-18T19:13:44Z")
Per the experts at UpToDate: > [@](#): > > In otherwise healthy adults with influenza infection, viral shedding can be detected 24 to 48 hours before illness onset but is generally at much lower titers than during the symptomatic period > > The average duration of influenza virus shedding in immunocompetent patients is five days. Shedding typically ceases after six or seven days but may continue for up to 10 days or more, particularly in children, older adults, patients with chronic illnesses, and immunocompromised hosts. Take that for what it’s worth. But if you still have symptoms, particularly coughing and excessive secretion production, you may still be contagious. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [February 18, 2018, 7:21pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/4 "2018-02-18T19:21:24Z")
Oh crap, I was around persons 5 or 6 days ago they were well, now one has confirmed flu. Another is ill. I assume I am coming down with something. I have scratchy throat. Tamiflu is scarce in these parts. Just my luck. ---
**Author:** ![LH75](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lh75/32/4438_2.png) [@LH75](https://boards.straightdope.com/u/LH75)\ **Post date:** [February 18, 2018, 8:01pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/5 "2018-02-18T20:01:30Z")
The excessive coughing is the worst part of this. I have been to my doctor twice. Each time he has prescribed Codeine cough syrup. This guy obviously doesn’t do the math. A prescription is 100ml. The dosage is 10ml every 4 to 6 hours. using the 6 hour interval, this gives me codeine for 60 hours or 2 1/2 days. If there was a chance that the cough will be cured in that amount of time, this would be all well and good. I have had this cough for more than three weeks. I would bet cash money that if my doctor was sleeping on the couch so his never ending cough won’t keep his wife awake, he would come up with something to stop the cough… ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [February 18, 2018, 8:32pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/6 "2018-02-18T20:32:29Z")
> [@LH75](#): > > I would bet cash money that if my doctor was sleeping on the couch so his never ending cough won’t keep his wife awake, he would come up with something to stop the cough… If I was your doc, you’d lose. I avoid opioids and ride it out. No fun, but there it is. For the cough of influenza, nothing but opioids really help. And I suspect your Rx says “take _if needed_ for cough”. When I do prescribe codeine for horrible coughs, I tell my patients they can take it up to 4 x a day, but it won’t last long that way. Save it for the horrible cough that won’t let you sleep. ---
**Author:** ![LH75](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lh75/32/4438_2.png) [@LH75](https://boards.straightdope.com/u/LH75)\ **Post date:** [February 18, 2018, 8:42pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/7 "2018-02-18T20:42:16Z")
I agree. The codeine I got (two prescriptions a couple of weeks apart) was used sparingly so we could sleep. that was all gone last Thursday. I have been toughing it out since, but I am pretty tired of the cough. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [February 18, 2018, 8:50pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/8 "2018-02-18T20:50:37Z")
“Flu” is short for “_influenza di stelle_”, so check your horoscope to find out. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [February 18, 2018, 10:43pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/9 "2018-02-18T22:43:56Z")
> [@SanDiegoTim](#): > > Assuming one can get to this point, what exactly makes someone non-cantageous? You can’t. My mother has gone down with it for the second time. ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [February 19, 2018, 4:11pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/10 "2018-02-19T16:11:55Z")
I had to take my wife to the doctor for flu and asked the exact same question. The doctor said that after you get the flu as long as you don’t have a fever you’re no contagious. That makes sense since a fever if your body’s way of fighting off an infection. No fever after you have been sick means no infection and you’re no longer contagious. Note you could be contagious before you get a fever at the beginning of the infection. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [February 19, 2018, 5:02pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/11 "2018-02-19T17:02:31Z")
> [@dolphinboy](#): > > I had to take my wife to the doctor for flu and asked the exact same question. The doctor said that after you get the flu as long as you don’t have a fever you’re no contagious. That makes sense since a fever if your body’s way of fighting off an infection. No fever after you have been sick means no infection and you’re no longer contagious. Note you could be contagious before you get a fever at the beginning of the infection. Sadly that doc is incorrect. Absence of fever is no sure indicator of lack of infectiousness for both colds and influenza. Viral shedding is seen in many patients who are not running fevers. ---
**Author:** ![treis](https://avatars.discourse-cdn.com/v4/letter/t/bc79bd/32.png) [@treis](https://boards.straightdope.com/u/treis)\ **Post date:** [February 19, 2018, 5:08pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/12 "2018-02-19T17:08:28Z")
> [@SanDiegoTim](#): > > Assuming one can get to this point, what exactly makes someone non-cantageous? How does one really know they’ve gotten to this point? Your immune system eventually destroys the virus and once that happens you’re no longer contagious. Symptoms persist because of the physical damage the virus and your immune system has done. So there’s some time while you’re still sick but the virus is out of your system. We know that is typically a week or so. That doesn’t mean everyone in every situation is no longer contagious. The only way to do that would be to test saliva or other fluids. ---
**Author:** ![Shinna\_Minna\_Ma](https://avatars.discourse-cdn.com/v4/letter/s/f08c70/32.png) [@Shinna\_Minna\_Ma](https://boards.straightdope.com/u/Shinna_Minna_Ma)\ **Post date:** [February 19, 2018, 5:18pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/13 "2018-02-19T17:18:37Z")
One year when I had the flu, the HR person in our office told me (over the phone) that I could return to work when I had gone 24 hours without a fever. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 19, 2018, 5:22pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/14 "2018-02-19T17:22:06Z")
**Qadgop the Mercotan** , a question I’ve always had with the viral shedding and contagion risk question is what degree of viral shedding is clinically significant? The issue is not just if the virus is in the nasopharyngeal secretions but also how likely those secretions are to reach others (hence more forceful coughs and sneezes associate with greater contagion risk). In any case [my FWIW contribution](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2954014/): > [@](#): > > … Transmissibility of influenza viruses depends on duration of shedding, amount of virus shed, and other factors that may facilitate projection of virus into the environment, such as coughing or sneezing. Challenge studies in healthy volunteers inoculated with seasonal influenza viruses have shown that shedding generally coincides with symptom onset starting 1 day after inoculation, peaks on the second day, and generally ends 1 week after disease onset, on day 8 (2). Duration of shedding is greatly affected by age, and for seasonal influenza viruses is longer in young children than in adults (3–5). Since the emergence of pandemic (H1N1) 2009, the recommended duration of self-isolation has varied from complete resolution of symptoms to 1 day after fever has subsided (6,7). … > > … Human challenge studies with seasonal influenza have shown that virus shedding after day 7 is rare (2), but clinical studies have shown that shedding may persist beyond that period in some populations, such as elderly persons, immunocompromised patients, and children (3–5,10–12). In a study among hospitalized persons infected with seasonal influenza A viruses, 54% remained positive by PCR beyond 7 days after symptom onset, and 29% were positive by cell culture (13). In another study, elderly hospitalized patients infected by influenza A (H3N2) viruses had higher virus loads than did outpatients, and their PCR positivity rate 1 week after disease onset was still high (57%) (10). > > In this prospective study, the proportion of pandemic (H1N1) 2009–infected persons still shedding replicating virus on day 8 varied from 8% to 13%, with no difference between children and adults. None were still shedding infectious virus on day 11. With seasonal influenza, virus shedding may be longer in children because they have less preexisting immunity that would limit replication than in adults. However, children and adults \<50 years of age appear equally susceptible to infection with pandemic (H1N1) 2009 virus, which would support our findings of comparable virus replication and shedding across age groups studied (1). … ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [February 19, 2018, 7:58pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/15 "2018-02-19T19:58:38Z")
> [@Qadgop\_the\_Mercotan](#): > > If I was your doc, you’d lose. I avoid opioids and ride it out. No fun, but there it is. For the cough of influenza, nothing but opioids really help. > > And I suspect your Rx says “take _if needed_ for cough”. When I do prescribe codeine for horrible coughs, I tell my patients they can take it up to 4 x a day, but it won’t last long that way. Save it for the horrible cough that won’t let you sleep. Yeah - when I have bronchitis or whatever, I’ve been given The Good Stuff but cautioned not to use it :D. Because if you’ve got a productive cough, you don’t _want_ to suppress it (that way, I gather, lies pneumonia). But I’ve gotten it a handful of times when the coughing was truly intractable and severely interfering with my sleep, and told that I was to use it just for that purpose (and to tough it out during the day). Though if I ever get bronchitis as badly as I did in 2016, I may whine and ask for more… the coughing was so severe it was aggravating a normally-quiescent disc problem (which of course made coughing agony), and I think tore a muscle in my side that still twinges now and then. In my case I was actually given a script for codeine when I didn’t ask for it, which may be the trick (as well as being an established patient of that doctor with a history of asthma / bronchitis, and no history of opioid issues). Also QtM deals with a rather different patient population than my suburban internist’s practice, and they are higher risk for abuse issues. Back to the OP: I imagine that once it’s all over but for the lingering cough, contagion is no longer an issue. And you sound horrible to everyone around, which doubtless causes them to give you a wide berth, which further reduces the risk! ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [February 19, 2018, 9:03pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/16 "2018-02-19T21:03:49Z")
> [@Mama\_Zappa](#): > > QtM deals with a rather different patient population than my suburban internist’s practice, and they are higher risk for abuse issues. Not by at much as most people think, though. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [February 19, 2018, 10:27pm UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/17 "2018-02-19T22:27:43Z")
> [@DSeid](#): > > **Qadgop the Mercotan** , a question I’ve always had with the viral shedding and contagion risk question is what degree of viral shedding is clinically significant? The issue is not just if the virus is in the nasopharyngeal secretions but also how likely those secretions are to reach others (hence more forceful coughs and sneezes associate with greater contagion risk). Excellent question; I’ve not found any real studies on that. ---
**Author:** ![Patx2](https://avatars.discourse-cdn.com/v4/letter/p/73ab20/32.png) [@Patx2](https://boards.straightdope.com/u/Patx2)\ **Post date:** [February 20, 2018, 12:43am UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/18 "2018-02-20T00:43:56Z")
> [@Shinna\_Minna\_Ma](#): > > One year when I had the flu, the HR person in our office told me (over the phone) that I could return to work when I had gone 24 hours without a fever. That’s what our school district tells parents, 24 hours fever free without fever reducing medication. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [February 20, 2018, 3:57am UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/19 "2018-02-20T03:57:18Z")
> [@Qadgop\_the\_Mercotan](#): > > … For the cough of influenza, nothing but opioids really help. > > … Can you explain this? ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [February 20, 2018, 4:25am UTC](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060/20 "2018-02-20T04:25:47Z")
It is odd, because I had that cough. I coughed so hard that I thought I was going to barf, and my abdominal muscles were sore top and bottom. I lost a full night’s sleep to that cough. But as far as I could tell, I was never really feverish or totally wiped out, and I never did barf. It seemed like just a really bad cold, but in my chest, where I rarely get a cold. If I had the flu, half of it was missing. [Next page](https://boards.straightdope.com/t/the-flu-im-not-contagious-anymore/809060.md?page=2)