When you think about fatal illnesses, the flu isn’t the first disease that comes to mind. However, the flu is a serious illness that can lead to hospitalization and sometimes can be deadly. Every flu season is different, and influenza infection can affect people differently. Even healthy people can get very sick from the flu and spread it to others.
Over a period of 31 seasons between 1976 and 2007, estimates of flu-associated deaths in the United States ranged from a low of about 3,000 to a high of about 49,000 people. During a regular flu season, about 90% of deaths occur in people 65 years and older. The flu season in the United States can begin as early as October and last until May.
An annual flu vaccine (either the flu shot or the nasal-spray flu vaccine) is the best way to reduce the chances that you will get the flu and spread it to others. When more people get vaccinated, less flu can spread through the community.
Flu vaccines work by causing antibodies to develop in the body about two weeks after vaccination. These antibodies provide protection against infection from the viruses that are in the vaccine.
The seasonal flu vaccine protects against the flu viruses that research indicates will be most common during the upcoming season. Traditional flu vaccines (called trivalent vaccines) are made to protect against three flu viruses; an influenza A (H1N1) virus, an influenza A (H3N2) virus, and an influenza B virus. In addition, this season, there are flu vaccines made to protect against four flu viruses (called quadrivalent vaccines). These vaccines protect against the same viruses as the trivalent vaccine as well as an additional B virus.
There are three different standard dose trivalent shots. The standard dose trivalent shots manufactured using virus grown in eggs are approved for people 6 months and older. A standard dose trivalent shot containing virus grown in cell culture is approved for people 18 and older. There is also an egg-free shot approved for people 18 through 49 years of age.
There is a high-dose trivalent shot approved for people 65 and older. Plus there is a standard dose intradermal trivalent shot, which is injected into the skin instead of the muscle and uses a much smaller needle than the regular flu shot. This is approved for people 18 through 64 years of age.
There is a standard dose quadrivalent flu vaccine, given as a nasal spray, approved for healthy people 2 through 49 years of age. (Healthy indicates persons who do not have an underlying medical condition that predisposes them to flu complications.)
The CDC does not recommend one flu vaccine over another. The important thing is to get a flu vaccine every year. Talk to your doctor or nurse about the best options for you and your loved ones.
Everyone who is 6 months of age or older should get a flu vaccine this season. This recommendation has been in place since 2010 when the CDC voted for universal flu vaccination in the United States to expand protection against the flu to more people.
While everyone should get a flu vaccine this season, it’s especially important for some people to get vaccinated, including those who are at high risk of developing serious complications (like pneumonia) from the flu. People who have certain medical conditions including asthma, diabetes, and chronic lung disease should be vaccinated, as should pregnant women, kids under 5 years old, especially those under 2 years old and those 65 and over.
If you live with anyone who is at high risk of developing serious complications from the flu, you should be vaccinated as well.
People who have had a severe allergic reaction to eggs may be advised not to get vaccinated. People who have had a mild reaction to eggs—that is, one which only involved hives—may receive a flu shot with additional precautions. Make sure your health care provider knows about any allergic reactions. Most, but not all, types of flu vaccine contain a small amount of egg. Children under two and people who have had an allergic reaction to the flu vaccine should not be vaccinated.
Flu vaccination should begin soon after the vaccine becomes available. Thus if you haven’t gotten it yet, get it soon. While seasonal influenza outbreaks can happen as early as October, most of the time flu activity peaks in January or later. Since it takes about two weeks after vaccination for antibodies to develop in the body, it is best that you get vaccinated soon, so you are protected before the flu begins spreading in the community.
A flu vaccine is needed every year because flu viruses are constantly changing. It’s not unusual for new flu viruses to appear each year. The flu vaccine is updated annually to keep up with the flu viruses as they change.
Also, multiple studies conducted over different seasons and across vaccine types and influenza virus subtypes have shown that the body’s immunity to influenza viruses (acquired either through natural infection or vaccination) declines over time.
Even if you get vaccinated, there is still a chance that you can get the flu. The age and health status of the person who is vaccinated, and the similarity between the viruses used to make the vaccine and those circulating in the community, factor into how well the vaccine will work. If the viruses in the vaccine and the influenza viruses circulating in the community are closely matched, vaccine effectiveness is higher. If they are not closely matched, vaccine effectiveness can be reduced. However, it’s important to remember that even when the viruses are not closely matched, the vaccine can still prevent flu-related complications. Such protection is possible because antibodies made in response to the vaccine can provide some protection (called cross-protection) against different but related influenza viruses.
It’s not possible to predict with certainty which flu viruses will predominate during a given season. Over the course of a flu season, the CDC studies samples of flu viruses to evaluate how close a match there is between the viruses used to make the vaccine and the ones circulating. In addition, the CDC conducts studies each year to determine how well the vaccine protects against illness during that season. The results of these studies are typically published following the conclusion of the flu season and take into consideration all of the data collected during the season.
Many people believe that a flu vaccine can cause the flu. It can’t; however side effects can be associated with the flu shot and nasal spray flu vaccines. These side effects are mild and short-lasting, especially when compared to symptoms of the flu. Some minor side effects that could occur are redness or swelling where the shot was given; low grade fever, aches, runny nose, headache, muscle aches and cough.
If these problems occur, they usually begin soon after vaccination and are mild and short-lived. Most people who receive the vaccine have no side effects. However, on rare occasions, flu vaccination can cause allergic reactions.
Getting a flu shot today can save you a lot of aches and pains this winter—just check with your doctor first.
