Tamiflu might help you feel better and shorten your contagious period.
When you have the flu, you may worry about transmitting the virus to members of your family or other people you come into contact with. Antiviral medications such as oseltamivir phosphate, better known as Tamiflu, taken early in an illness can reduce the duration and severity of flu symptoms and may also reduce the length of time that you shed the virus. It does not, however, stop viral shedding altogether. You can still pass the virus to another person for a while after starting the drug.
Tamiflu acts by reducing the number of cells in your body that are affected by the influenza virus. It does this by binding to a coating, called neuraminidase, that's found on the surface of the virus. Neuraminidase allows the virus to penetrate healthy cells, where it can then produce more copies of the virus. When Tamiflu binds to neuraminidase, the virus can no longer penetrate cells, blocking replication and reducing the amount of virus circulating in the body. The sooner you take the drug, the sooner it begins working. Once the number of infected cells reaches a certain point, Tamiflu and other antivirals can no longer effectively contain the virus.
Influenza spreads mainly by respiratory droplets that contain copies of the virus that have replicated in your body. Viral shedding, which correlates with infectivity, occurs starting approximately 1 day before symptoms appear and can continue for up to 10 days after symptoms develop. The most active period of contagion falls between 1 and 4 days after the start of symptoms, according to a May 2010 article published in the "Journal of Infectious Disease." The study also found that in a small number of cases, infection transmission occurred before symptoms appeared.
Several studies have looked at the effect of Tamiflu on whether a person remains contagious from the flu, but the results have not been consistent. An article in the February 2001 issue of the "Journal of the American Medical Association" found that when oseltamivir was given to individuals with flu symptoms within 48 hours after their symptoms started, 89 percent of the people in their households did not contract the flu. In 84 percent of cases, the entire household remained influenza free. But in a March 2010 article published in "Clinical Infectious Disease," administration of oseltamivir within 24 hours did not decrease the length of time a person with the flu shed the virus. The risk of contacting the flu in other household members was only reduced to approximately 50 percent.
Timing of Tamiflu
The sooner you start Tamiflu after developing flu symptoms, the more likely your symptoms are to be of short duration and the more likely that viral shedding will decrease more rapidly. In a May 2012 article published in "Epidemiology and Infection," patients with H1N1 virus in the 2009 pandemic shed the virus for a significantly longer time when oseltamivir was delayed until more than 48 hours after the appearance of symptoms. According to the Centers for Disease Control and Prevention, whether you take Tamiflu or not, you should wait at least 24 hours after your fever has disappeared before returning to school or work to help prevent spread of the flu.