As the weather turns colder, it’s that time of year to start thinking about influenza (flu) prevention. While people often associate everything from gastrointestinal illness to routine colds with influenza, it’s important to understand what it is and what it isn’t in order to protect yourself and your family.
Influenza is a very contagious illness that tends to occur in outbreaks. The majority of illnesses caused by the flu are self-limited and often mild to moderate in severity. There are three types of influenza viruses: A, B and C. Human influenza A and B viruses cause seasonal epidemics of disease almost every winter in the United States. The emergence of a new and very different influenza virus to infect people can cause influenza outbreaks and epidemics. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics.
The typical flu symptoms include acute onset of muscle aches, fever as high as 103 degrees Fahrenheit, upper respiratory symptoms including sore throat, runny nose, cough and extreme fatigue.
Gastrointestinal symptoms are less common in flu. Although often called the “stomach flu,” these type of illnesses that cause nausea, diarrhea and vomiting are typically caused by rotaviruses or bacteria and aren’t related to influenza.
While everyone should be concerned with influenza, certain people are at high risk for complications of the flu. This includes the elderly, the very young and people with chronic medical conditions including diabetes, COPD and those who are immune compromised.
Prevention is the key to decreasing the incidents of outbreaks and epidemics. The Centers for Disease Control recommends flu vaccine for all individuals six months and older. The vaccination period for the flu begins in August and ends in April. There is a two-week lag time between receiving the vaccine and having adequate immunity against the flu. Several vaccines are available for influenza A and B. These vaccines contain antigens developed based on best medical knowledge from prior history of influenza outbreaks. An antigen is any substance that causes your immune system to produce antibodies against it.
Available vaccines are:
- Trivalent vaccine – This is the most traditional flu vaccine that is made to protect against three different flu viruses.
- Quadrivalent vaccine – Like the trivalent vaccine, but contains four influenza antigens.
- Intradermal trivalent vaccine – Contains a low amount of antigen which is injected into the skin, instead of the muscle, with a much smaller needle. This is preservative-free and given to individuals 18 to 64 years of age.
- High-dose vaccine – Contains four times the amount of antigen than the normal flu vaccine. It is indicated for patients 65 and older. Studies have shown a significantly higher antibody response in patients who receive this vaccine and preliminary data show a decrease rate of influenza.
- Nasal vaccine — This vaccine is indicated for patients 2 years to 49 years of age. It is a live, attenuated vaccine so it should not be given to pregnant, those who are immune compromised or children with significant asthma.
Certain vaccines are preservative-free, meaning they do not contain Thimerosal, a mercury containing substance.
Despite the best efforts, some patients do develop flu. Most cases are self-limited and are treated with nothing more than supportive care including fluids, rest and over-the-counter medications. Two antiviral drugs are available to treat acute flu. They are Oseltamivir (Tamiflu) and Zanamivir (Relenza). These medications are used in high-risk individuals including patients with COPD and diabetes. Additionally, use of these medications is considered in both the very young and the very elderly. All individuals suspected of having the flu should stay home from work or school to decrease the risk of outbreaks. As with all viral illnesses, one of the best ways to prevent the spread is good old-fashioned hand washing.