Influenza FAQ

Influenza FAQ

What is influenza, and what is H3N2?

Influenza is the name of a very large and diverse family of viruses that infect the human respiratory tract. The disease caused by those viruses is also called influenza, and it afflicts roughly 60 million Americans annually, particularly in the winter months (hence the common name “seasonal flu”). There’s a brand-new strain of influenza called H3N2, a variant of a common subtype of influenza, and it’s different from the viruses that typically cause seasonal flu. The new strain is now commonly known as “swine flu” or just “H3N2.”

How serious is influenza?

For the most part, seasonal influenza and H3N2 influenza do not pose serious health risks to individuals. More than 99 percent of all infections cause fairly mild symptoms and get better on their own. Severe illnesses and deaths are very rare. (Less than 1 percent and less than 0.1 percent, respectively.) H3N2 is generally less severe than seasonal flu.

How does influenza spread?

Both seasonal and H3N2 influenza spread person-to-person. H3N2 does not spread via animals or food (e.g., pork). An infected person can transmit influenza by coughing or sneezing, sending virus-containing droplets onto nearby people and surfaces. The virus can then survive on surfaces up to eight hours.

What are the symptoms?

The symptoms of influenza are usually more severe than the symptoms of a common cold. Symptoms typically develop one day to seven days after exposure, and can last from a few days to two weeks. They may include any or all of the following:

  • Fever (usually 100°F or warmer, lasting for several days)
  • Body aches or muscle aches
  • Headaches
  • Fatigue
  • Sore throat
  • Runny or stuffy nose
  • Cough
  • Diarrhea
  • Nausea and sometimes vomiting

Uh-oh. I think I have influenza. How can I tell whether I have H3N2 or seasonal influenza?

The only way to distinguish between the two viruses is to do a special test, which can take several days and is not 100 percent reliable. Fortunately, for the vast majority of patients, it doesn’t matter. We treat both illnesses the same way.

But I still need to be tested, right?

Not necessarily. Testing for influenza isn’t always helpful, particularly during an outbreak. If you’ve got the symptoms, we can be reasonably sure you’ve got the disease, and we’ll treat you accordingly. In most scenarios, it’s better for you to stay at home and rest, rather than come to the office for a useless test. However, there are a couple of exceptions. If you think you’ve been exposed to swine flu, or are concerned that your symptoms might signal something other than the flu, then you should get tested, especially if your symptoms occur outside of flu season. Why? It won’t affect your treatment plan, but it’s an important act of social responsibility that will help the CDC track pandemics and plan future vaccines.

So what should I do if I get sick?

Whether you’ve got H3N2 or seasonal flu, there’s really no substitute for old-school, common-sense treatments. Get lots of rest and drink plenty of fluids. Avoid alcohol and tobacco. Take acetaminophen (Tylenol) and/or ibuprofen (Motrin, Advil) for fever and body aches, but avoid aspirin if you’re under the age of 19. You should start feeling better within a few days. If you are at risk for complications of influenza (see below), or if your symptoms are clearly getting worse, call our office and ask to speak with someone on our medical staff for more advice.

How can I prevent making other people sick? When can I go back to work/school?

Wash your hands frequently, cough and sneeze into your arm (not your hands) and throw out tissues immediately after use. Most importantly, stay home. Don’t return to work or school until you have had a normal body temperature (under 100°F without taking a fever-lowering medication such as Advil or Tylenol) for at least 24 hours. And please don’t come to our office without calling first!

How long will I be contagious?

You’re contagious from the day before you develop symptoms until 24 hours after your fever breaks.

Do I need to wear a mask while I’m sick?

No, not if you stay home and can remain at least six feet away from other people. However, if you simply must be in close contact with others (e.g., for an airplane flight), then consider wearing a surgical mask. This is especially important if you will be in contact with people at risk for complications of influenza (see below). For example, sick mothers who are nursing infants should strongly consider wearing a mask for the duration of the illness.

Do I need an antiviral medication (e.g. Tamiflu)?

Usually not. Most people with influenza will recover completely without medication. Drugs like Tamiflu can help shorten the duration of symptoms and help lessen the severity of symptoms by a day or so, but they won’t cure and won’t reliably prevent influenza. In fact, overzealous use of these drugs has the potential to contribute to the emergence of resistant super-viruses. However, if you have influenza and you are at risk for complications (see below), you should receive antiviral medication. In that case, please call our office to speak with someone on our medical staff as soon as possible, since antiviral the drugs work best if taken within two days of becoming ill.

How do I know if I’m at risk for complications of influenza?

You are at increased risk for complications if:

  • You are pregnant
  • You have a chronic medical condition, such as diabetes, obesity, heart disease, kidney disease, liver disease, asthma, emphysema, cancer, HIV, etc.
  • You are age 65 or older
  • You are younger than age 5
  • You are younger than age 19 and are receiving long-term aspirin therapy

If you fall into any of these categories and are feeling sick, or have been exposed to someone with a confirmed case of influenza, please call our office and ask to speak to a medical staff member for further guidance.

When should I go to an emergency room?

You should go directly to an emergency room for further evaluation and treatment if you have any of the following symptoms:

  • Difficulty breathing
  • Pain or pressure in the chest or abdomen
  • Bluish skin color
  • Confusion or sudden dizziness
  • Persistent or severe vomiting

Yuck. I definitely don’t want to get influenza. How can I protect myself from getting sick?

  • Wash hands with soap and water or hand sanitizer frequently. Be aware of touching common surfaces like doorknobs, faucets, phones, keyboards, etc., and wash hands afterward. Avoid touching your eyes, nose, or mouth unless you have clean hands.
  • Try to stay at least six feet away from people who appear ill, and avoid sharing food, drinks, toothbrushes, etc. during an outbreak. Wearing a mask is not necessary.
  • Keep your immune system healthy. Get plenty of sleep (8 hours a night is ideal), drink plenty of water, and eat plenty of fruits and vegetables. Avoid alcohol, tobacco and other unhealthy vices!
  • Get vaccinated! (See below for details.)

I’ve been exposed to someone with influenza! Will I get sick?

There’s no way to know for sure, but if you’ve followed the guidelines above, and especially if you’ve received the appropriate vaccinations, you’ve got a very good chance of remaining healthy. On the other hand, if you are in the at-risk group described above, you should consider taking an antiviral medication like Tamiflu to further reduce your chances. Please call our office to discuss this with someone on our medical staff.

Should I get a seasonal flu shot?

Ideally, yes, you should! Everyone stands to benefit from getting a seasonal flu shot, but it’s especially important if you’re pregnant (or planning to become pregnant), over the age of 50, have any sort of chronic medical condition, or are caring for someone who is at risk for complications of influenza.

Are flu vaccines safe?

Generally, yes. Influenza vaccines, including the H3N2 vaccine, have been studied carefully and are generally very safe. However, if you’ve had an allergic reaction (or other bad reaction) to a vaccine in the past, be sure to let us know before you receive any vaccine.

Where can I learn more?

San Francisco Health Department influenza website
New York City Health Department influenza website
District of Columbia Health Department influenza website
Boston Health Department influenza website
Chicago Health Department influenza website
CDC: FAQs for the 2012-2013 Flu Season

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  1. Robert says:

    Can flu shots be given during my annual physical? Is there a time into the flu season when it is too late to establish resistance before the season ends?

    • Hi Robert. To answer your question, yes, flu shots can be given during the annual physical. And it is never too late to get one – obviously, it is best before flu season, say in October or November, but late is much better than never.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  2. Neal says:

    Last time I had a flu shot, my arm blew up, became very swollen, and I ended up being sick on and off for about 6 weeks with fever and farengitis.If I get the flu shot again, would I have the same or worse reaction? Also- is it possible to have the flu shot divided up into 2 doses, take half the shot, then come back a week later take the second half in order to have less of a bad action?

    • Hi Neil

      Allergic reactions or sensitivities to the flu vaccine can be common. The swelling in your arm can be managed with ice and ibuprofen. It’s not uncommon to experience a few days of fever, headache, and body aches. The other symptoms you describe, however such as being sick for 6 weeks with pharyngitis, are not typical. It may be that you coincidentally got the flu shot the same time you picked up another non-flu respiratory infection. I recommend reporting these symptoms to your health care provider and having him or her file a report with the Centers for Disease and Control and Prevention (CDC) on its vaccine adverse reactions site. They can advise on next steps before getting your next vaccine. This can be done in a few days, and I recommend waiting for a reply before you get the shot.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  3. gloria whelan says:

    as well as the flu symptoms I had chronic head and earache , but not diarrhea. when my throat was sore and i coughed , pain shot to my ears and was horrendous, is it possible that I had something other than flu.

  4. Sheryl says:

    I work in long term care home. There’s currently a respiratory outbreak in one of our unit. We have one confirmed case of influenza A so far. I am 10 weeks pregnant and I did get my flu shot on October. Is it advisable for me to go to work with all the possible complications I may encounter if I do get influenza?

  5. Tracy says:

    I’ve had the flu since Tuesday (today is Sunday) & have been to ready-care 2x. I have this very wet cough and blowing my nose (a lot) yet & don’t know whether to go to work tomorrow yet. Help? (No fever, but still taking ibuprofen)

  6. Tina says:

    Hi! I’ve had the flu for about a week and a half now, And I just can’t seem to shake it. I have to go back to school 5 hours away this weekend. I can barely build up energy to get out if bed. Could it possibly be something worse?

  7. Bob says:

    It’s been 6 days since I had flu A.
    Can I get on plane?

  8. John says:

    I have been taking tamiflu since Wednesday night 1/9/13 and today is Saturday 1/12/13 is it still normal to have body aches. I ve been taking 3 Advil every 4 hrs and that works but when it wears off I can tell. Thank you for your response.

    • Hi John

      It’s very common to feel body aches or general weakness for a couple of days or even weeks after the flu. Nothing to be concerned about, it will pass. If you spike a fever again or suddenly develop signs of another infection, then you should contact your primary care provider. Otherwise just let time, rest and ibuprofen do the trick.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  9. Joe says:

    I went to my doctor Thursday morning after noticing weds night I started to feel bad. Gave me tamiflu, must say its Saturday now and I feel great. Is it because I caught the flu so fast within 24 hours ?

    • Hi Joe

      Very possibly, although we can never be sure. You may just had a mild case of flu or the early start on Tamiflu made a real difference. In either case, glad to hear you’re feeling better!

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  10. Marianne says:

    Two years ago I had swine flu so severely that I almost died from it & was hospitalized for 14 days – 5 days in ICU, next 5 still in isolation & remaining 4 in reg part of hospital. This was after the flu shot. Again this year I got the flu shot & I’ve been sick for almost two weeks now & almost finished a regimen of tamiflu, however, I still feel nauseous & feel like vomiting still. I also have relentless fever & chills – do I take tylenol for that or is the tamiflu supposed to be addressing that?

    • Hi Marianne,

      Unfortunately, we can’t provide specific medical advice online. We encourage you to get in touch with your primary care provider to look into this further for you. We hope you feel better!

  11. Linda says:

    Am I still contagious if my fever broke on Friday and have began Tamiflu meds?

    • Hi Linda

      It is impossible to say with certainty how long someone is contagious. The usual rule of thumb is a person is contagious from 1 day prior to symptoms to 7 days after the illness has begun. Tamfilu may help shorten the contagious period by a day or so, but this isn’t certain. It’s best to assume you are contagious for about a week. Get well soon!

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  12. Phyllis Priest says:

    We ALWAYS get flu vaccine (IM) for our medically fragile kids ranging in age from 5-19, and this year all but two of them have gotten influenza. The kids at highest risk were prescribed Tamiflu and the difference in their course of illness and recovery is amazing. Even so, they will miss at least a week of school. I know Tamiflu is prescribed for 5 days—is that the limit of its effective course of treatment?

    • Hi Phyllis

      Yes – 5 days is the limit for treating active flu. By the final day of treatment, the antivirals have completely killed the virus so there is no advantage in continuing the medication.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  13. monica says:

    Hi, I started flu symptoms on Monday, started tamiflu on wednesday. I still have a headache and today is Thursday. Is it normal to have a headache this long?

    • Hi Monica

      Yes – having low-level flu symptoms like headache to persist for days (even weeks) is normal. In most cases, the worst of the symptoms usually resolve in 3-5 days. No reason to be concerned – hydrate well, listen to your body, and get plenty of rest. If you continue to have symptoms by next week, I’d suggest contacting your primary care provider to look into further.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  14. Leona Bush says:

    Is it okay to take an advil for the flu, if I had an aspirin 7 hours ago?

  15. CB says:

    I’ve been tested by my chiropractor/kinesiologiost for virus and have come up positive for 10 days. I’m out of bed but still feel viral. When will this thing end? Do I need to stay in and not go about my social life?

  16. John says:

    After 3 years of health. I foolishly let a bad cold evolve without meds. 5 weeks into it cold symptoms long gone. Still achy, weak. temperature below normal. Dr. prescribed tamiflu . I did not take it after reading it only works within 48 hours of onset. And then just shortens duration by 1 or 2 days.

    Long story short, I am not in my 7 th week of feeling rundown and my head and body ache and I am weak.
    I was on Naproxen for 2 weeks but ready to try something else.
    My toes are showing signs of bad circulation, a new development. I am in house resting. I didn’t rest enough around the holidays when I first got sick and my diet wasn’t good because of holidays. help me please.

  17. cheryl says:

    I got the influenza vaccine in November 2012. The next day I noticed my arm was swollen and red around the injection site, which I know is normal. I’ve been sick all winter with a consistant cough and flu like symptoms. My arm is still very swollen and the injection site still has a bump and is red. Could I still be having a allergic reaction? Has this ever been reported before?

    • Hi Cheryl

      It would be very unusual for all of these symptoms to be related to the flu shot. It’s possible the injection hit a small blood vessel and created a small bruise that may last a long time. It’s probably best for you to see your health care provider to both look at the arm and reassess you symptoms.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  18. Erica says:

    My daughter (10 years old) had a fever tues night…we took her to the doctor on fri…they checked her for strep throat and it came back negative…they also did another test where they swabbed the inside of her nose…we are waiting for those results on mon…I don’t understand why her fever keeps coming and going…it’s been six days…she is active and has a good appetite when the fever is gone…should a fever for the flu last this long? All he told us was to give her cough medicine and ibuprofen which we have been doing

    • Hi Erica, a lingering fever from the flu can sometimes last this long in some cases. The nasal swab may be for pertussis and/or flu so you should make sure to check on those results. If her fever doesn’t break in a couple more days, you should have her checked by your pediatrician.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  19. ruthi says:

    i got the influenza vaccine last week wednesday 13th feb.afterthat that day evening onwards i felt body ache.both arms and legs muscles and bones are fingers joints also pain still its continue .is it normal?

    • Hi Ruthi–it’s uncommon to have symptoms this prolonged since you received the vaccine (but not unheard of.) If everything doesn’t return to normal in a few days, you should contact your primary care provider to look into further for you.

      Malcolm Thaler, MD
      Clinical Editor
      One Medical Group

  20. Roger Gietzen MD says:

    I understand the CDC recommends that everyone get vaccinated, but a careful review of the literature would suggest otherwise. It is very difficult to find unbiased reviews. Many are either slanted anti-vaccine, or paid for by Pharma and slanted that way. I highly recommend this review:;jsessionid=262C1F1D9FBA309D5972613B766D6E9C.d03t03

    Notice specifically the warning at the end of the study!
    Roger Gietzen, MD at Healthy Mind Body

  21. Jane says:

    I am in day 7 of the flu I presume, did not have the vaccine. I have had chest pain/congestion, body aches, headache, chills that shake my whole body, fever which will not break even with Ibuprophen. I cough up quite a bit of green phlegm every morning then just small amounts during the rest of the day and evening. My normal temperature is 97.7 but has been as high as 101.4, but consistantly 98.8 – 99.4. How long does the fever normally last with flu, or could this possibly be pneumonia?

    • Thanks for your question Jane. Flu symptoms can sometimes linger for a longer period of time. Best thing to do is get this checked out by your primary physician. He/she can take a closer look and see if they need to run any tests for things like pneumonia.

  22. Mary says:

    I have not gotten my flu shot yet, but have been exposed to 2 people who have it. One is my Grandson who slept 2 nights with me in the same bed. Should I get my flu shot now or wait a certain amount of time? Also, how long after exposure will the symptoms appear?

    • Hi Mary, it’s never too late to get your flu shot! Please note that if you’ve already been exposed to the flu virus, getting a flu shot after exposure will not prevent you from potentially getting sick. To answer your second question, please see our section above “Will I get sick if I’ve been exposed to influenza?”

  23. Ney says:

    My husband got really sick and went to the emergency. He got blood test and influenza test done. He had a small severe pneumonia on his right lung and he was positive in influenza. I am very scared that my kids catch this influenza. My little girl just wants to be with her dad. How can I prevent my kids getting a flu??

  24. Anna says:

    I’m on day 3 of what is almost certainly the flu. I’m 31years old and I have a high fever of 102-103℉ that is only controlled by staying ibuprofen. How long should I expect a high fever to be “normal” before seeking medical attention?

  25. Francinah says:

    I had a sore throat and was a doctor who gave me an injection and some antibiotic. When I got better from sore throat I developed flu and it has bee 2 weeks now can’t shake it off

  26. Carla says:

    Saturday evening went to bed feeling fine. I was up all night with lower back pain. Sunday lower back pain didm”t subside and got worse through the night. I had a fever of 101 and took Advil and slept on a heating pad. Monday I felt way better so I went to work. I actually thought I had a 24 hour bug because I felt great. Monday evening felt fine until around 9:00. I had severe headache and body aches through the night. Today I couldn’t go to work. Do you have insight as to why I would feel good on Monday then take a turn for the worse? Not sure if this is the flu. I don’t have a cold or vomiting/diarrhea.

  27. RB says:

    When does your practice start giving flu vaccines?

    • Hi RB,

      Very soon–please keep an eye on our blog. We’ll keep you updated once we’re ready to start giving out flu vaccines for the upcoming flu season.

      Kameron Kitajima
      Community Manager
      One Medical Group

  28. Alexandra says:

    I had early flu like symptoms last night that came suddenly with feelings of intense fatigue, chills, and muscle aches. My temperature was 100.4 and this morning it went up too 100.9. I felt so sick but did not throw up. About an hour later, I started feeling better and now I feel normal, except for being a little hot but my temperate is back to normal. Is there an explanation as to why I would have these early flu like symptoms and then they go away the next day?

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