The flu is the infection by the influenza virus. Typically in the winter months it describes an illness with upper respiratory symptoms, fever, chills, body aches, and general fatigue. Patients say they feel like they’ve been slammed by a truck. It is important to truly understand influenza, appreciate the serious quality of this condition, and realize the possible implications and outcomes when you catch the flu.
What’s the difference between a virus and bacteria?
Viruses are not like bacteria. Bacterial cells are capable of all the functions associated with human life, including the ability to generate energy. Viruses are smaller than bacteria, made up of a protein coat and either RNA or DNA, and they need to penetrate host cells to survive and replicate. Bacterial and viral infections can cause similar symptoms. Antibiotics specifically target cells, which is why they are ineffective against viruses.
It’s hard to treat viruses, without a simple solution like an antibiotic, so doctors tend to try and treat symptoms. Doctors recommend taking the flu vaccine to limit disease and the complications that arise, especially among the most vulnerable, i.e. very young children, seniors, individuals who are immune-compromised, and individuals who have ongoing chronic diseases. The vaccine enhances the only defenses against viruses: antibodies. Recent statistics suggest that yearly 100,000 people can die from the flu and its complications.
The flu vaccine
Vaccines are developed before the flu season hits, so researchers and vaccine manufacturers speculate the anticipated strains, and anti-genetic properties are selected for the vaccine. It tends to be a bit of a gamble, and this year as you may know, the most virulent form has been H3N2. The vaccine was not matched for this specific strain of flu, so the vaccine is only about 33 percent effective this year.
This may be the result of the CDC paying more attention to the H1N1 strain that was responsible not only for a large prior epidemic, but also raised concerned about the specific virus moving from species to species, with the virus using animals as reservoirs or vectors. It’s still the recommendations of the public health and medical community that everyone be vaccinated, especially those at higher risk for complications. This is a highly infectious disease, and even a poorly matched vaccine will instigate antibodies that are a source of early defense.
How the flu virus works
Patients often present after getting the vaccine, with (viral) cold symptoms, and express anger that they’re sick. Although annoying, colds are self-limiting and contained, and the flu vaccine does not prevent colds. What makes the flu virus different and worrisome is its predilection for the upper airways (from the pharynx through the windpipe to the main airways). It causes death of the superficial layers of cells and leaves the inner airways vulnerable. As the virus invades this area, and the body mounts a response, it can result in production of copious secretions. Coupled with the fact that the mouth is naturally full of bacteria, this can also make someone vulnerable for lower lung infections, and specifically pneumonias caused by bacteria like Staphylococcus, which is a common cause of mortality.
People with chronic pulmonary diseases, such as COPD, are at high risk for flu complications. They already have the "clearing of secretions" mechanism compromised. Their cough, although more persistent, is relatively ineffective in helping to clear secretions. Unlike many viral illnesses, there is a rapid influenza test that can quickly and effectively identify those individuals who actually have the influenza virus. If identified, it offers an important window of opportunity to treat patients with an "anti-viral drug," which will limit symptoms and shorten duration of disease. It will also reduce unnecessary use of an antibiotic, which is ineffective and, unfortunately, the most frequent intervention.
The oral anti-viral medications currently recommended for use are Oseltamivir, Tamiflu, or Relenza. They do have some side effects, but if used in the first 24 to 48 hours of the illness they can be effective. The antivirals don’t kill the virus (remember they are not living organisms) but rather, prevent replication. This approach can help to limit the worrisome and sometimes fatal complications of the flu, especially in patients with COPD. If a secondary infection does occur, you may then require additional therapies, including an antibiotic.
Next up: The Pneumococcal Vaccine
Eli Hendel, M.D., is a board-certified internist/pulmonary specialist with board certification in Sleep Medicine. An Assistant Clinical Professor of Medicine at Keck-University of Southern California School of Medicine, and Qualified Medical Examiner for the State of California Department of Industrial Relations, his areas include asthma, COPD, sleep disorders, obstructive sleep apnea, and occupational lung diseases. Favorite hobby? Playing jazz music. Find him on Twitter @Lung_doctor.