Does Tamiflu Make You Non-Contagious?
No, taking Tamiflu (oseltamivir) does NOT make you non-contagious—you can still acquire influenza virus infection and transmit it to others even while on treatment or prophylaxis, though the medication does reduce viral shedding. 1
Key Evidence on Contagiousness While Taking Tamiflu
You Can Still Transmit Virus on Tamiflu
- Persons taking oseltamivir for chemoprophylaxis might still acquire influenza virus infection and be potentially able to transmit influenza virus, even if clinical illness is prevented. 1
- Person-to-person transmission of oseltamivir-resistant virus has been documented among healthy persons not receiving the medication, indicating that transmission can occur from those on treatment. 1
- Development of illness caused by oseltamivir-resistant virus has been reported among persons receiving oseltamivir chemoprophylaxis. 1
Tamiflu Reduces But Does Not Eliminate Viral Shedding
- Oseltamivir treatment significantly reduces virus isolation on days 2,4, and 7 after treatment initiation compared to placebo, but does not eliminate viral shedding entirely. 2
- In a Bangladesh study, even with oseltamivir treatment, 56% of patients still had detectable virus on day 2,30% on day 4, and 6% on day 7. 2
- Oseltamivir treatment was not associated with statistically significant reduction in the duration of viral shedding in one household transmission study. 3
Impact on Household Transmission
- Household contacts of index patients who took oseltamivir within 24 hours of symptom onset had a non-statistically significant lower risk of developing laboratory-confirmed infection (adjusted odds ratio 0.54), but evidence of household reduction in transmission was inconclusive. 3
- When used as post-exposure prophylaxis in household contacts (not treating the infected person), oseltamivir demonstrated 84% protective efficacy in preventing viral shedding in those contacts. 4
Clinical Implications for Isolation
Continue Standard Infection Control
- Careful attention to infection-control measures is recommended, particularly in hospital areas that house immunocompromised patients, regardless of antiviral treatment status. 1
- To limit transmission of drug-resistant virus, contact between persons taking antivirals for treatment and those taking prophylaxis should be reduced. 5
Duration of Contagiousness
- Persons treated with oseltamivir can shed susceptible viruses early in treatment and later shed drug-resistant viruses, including after 5-7 days of therapy. 1
- The medication reduces the duration and quantity of viral shedding but does not eliminate it completely. 6
Bottom Line for Practice
Patients on Tamiflu should continue standard respiratory isolation precautions and should not assume they are non-contagious. While oseltamivir reduces viral shedding by approximately 44-70% at various time points 2, transmission remains possible throughout the treatment course and potentially beyond. The medication is best viewed as reducing—not eliminating—contagiousness, and standard infection control measures remain essential. 1