You’re generally contagious with the flu for about 5–7 days from when symptoms start, and taking Tamiflu usually does not change that overall window, though it may reduce how much virus you shed and how sick you feel during it. Most people are less contagious once their fever has been gone for at least 24 hours without fever-reducing medicine and their symptoms are clearly improving, but young children and people with weak immune systems can stay contagious longer.

How long you’re contagious

  • Flu usually spreads from about 1 day before symptoms start to around 5–7 days after they begin.
  • You tend to be most contagious in the first 3–4 days of illness, when fever, cough, and aches are at their worst.
  • Children and people with weakened immune systems can shed virus for more than 7 days, sometimes significantly longer.

What Tamiflu changes (and doesn’t)

  • Tamiflu (oseltamivir) is an antiviral that can shorten how long you feel sick and reduce the amount of virus in your body, especially if started within 48 hours of symptoms.
  • Some sources suggest that antiviral treatment may modestly shorten the period of contagiousness by reducing viral shedding, but it does not instantly make you non‑contagious and may not change the total contagious window much for many people.
  • In practice, you should still follow standard “flu precautions” even after starting Tamiflu, because you can continue to spread the virus while on the medication.

Practical “when am I safe?” rule of thumb

Most doctors and public health sources use a simple return-to-normal-life rule:

  • It has been at least 5 days since your symptoms started.
  • Your fever has been gone for at least 24 hours without taking fever reducers like acetaminophen or ibuprofen.
  • Your symptoms (especially cough and overall energy) are clearly improving, not getting worse.

If all three are true, your risk of infecting others is much lower, even though a small amount of virus shedding can sometimes continue.

If you’re still feeling really sick

  • Stay home and avoid close contact (kissing, sharing drinks, crowded spaces), especially with infants, pregnant people, older adults, and anyone with chronic illness or a weak immune system.
  • Keep masking, covering coughs and sneezes, washing hands frequently, and cleaning high‑touch surfaces while you’re symptomatic.
  • Call a healthcare professional promptly if you have trouble breathing, chest pain, persistent high fever, confusion, or symptoms that worsen after initially improving.

“Quick Scoop” summary

  • You can spread flu from 1 day before symptoms to about 5–7 days after they start, sometimes longer in kids or immunocompromised people.
  • Tamiflu can help you recover faster and may reduce how contagious you are, but it does not instantly stop contagiousness and may not drastically change the overall timeframe.
  • A good safety rule: wait at least 5 days from symptom onset, be fever‑free 24 hours without meds, and feel clearly better before assuming you’re unlikely to be contagious, even if you’re taking Tamiflu.

Information gathered from public forums or data available on the internet and portrayed here.