Dr. Wojo. Healthy Living. Simplified.

Antivirals have taken center stage recently because of the continued proliferation of N1H1. Several people have requested I answer the following question - Just how does an antiviral, like Tamiflu, work? Further, if I have N1H1 this summer, am I immune in fall?

To answer the first question - the antiviral Tamiflu is the brand name for the generic drug, Oseltamivir, typically used to treat and prevent Influenza A and B. It has also been found to be effective against N1H1. As a flu treatment, an antiviral is most effective if taken within 48 hours of the onset of flu symptoms - if taken after that period of time, you simply may have too much of the virus within your body for the antiviral medication to be effective.

Tamiflu does not cure the flu - but it can reduce your symptoms, the length of your illness and your risk of developing serious complications like pneumonia. Nor does an antiviral kill the virus - instead, it stops or slows the replication of the virus in your body. Unlike bacteria, viruses cannot reproduce on their own - they are internal parasites that take rely on and over our cells in order to reproduce. When a virus is immune to the body’s defenses, it latches onto a cell, inserts its genetic material into the cell and makes replications of itself by taking over the cell’s reproductive machinery. The new viruses break out of the cell and take over new cells. Eventually, this leads to disease. Antivirals break down this reproductive process - and thus the spread of the virus to new cells - by trapping the virus within the cell, where the virus eventually dies.

Viruses such as the flu are spread when someone coughs or sneezes. It’s believed that antivirals also make ill patients less contagious because they have less virus to shed and are ill for less time.

Now, to the second question - about immunity gained by having the flu. First, let’s explain what an antibody is. They are proteins made by a person’s immune system to attack and destroy bacteria and viruses. Each virus and bacteria has antigens - chemicals on their surface - specific to them. The first time you are exposed to a new bacterium or virus, your immune system works to create antibodies specific to the antigens of the bacteria or virus. The antibodies then attach to the bacteria or virus and destroy it with the help of T cells. Some of the antibodies also remain within your immune system and are quickly reactivated the next time you are exposed to that same bacteria or virus - preventing you from becoming ill. The antibodies give you immunity. 

Thus, if you have already had N1H1, you could be immune to it in the upcoming months. While researchers note there is the possibility that N1H1 will mutate - possibly to a more virulent form - you should at least have partial immunity.

Also of note is the recent report by the CDC that individuals over the age of 60 appear to have a pre-existing immunity to N1H1. Typically, those over the age of 65 are more susceptible to influenza outbreaks, but tests done by the CDC on stored blood samples indicate that older individuals had greater amounts of swine flu-fighting antibodies present. It is believed that this is due to the fact that many older adults were either infected with or vaccinated against an older flu strain that closely resembles N1H1.