Influenza, colloquially referred to as the flu, is a contagious respiratory illness. It is very common; in a given year, around five to 20% of the population will become ill with the flu.
The flu is often characterized by symptoms like fever, sore throat, coughing, muscle weakness, nausea and vomiting, headache, chills, and fatigue. For most healthy adults, the flu is more irritating than dangerous, but older adults, children, anyone with a compromised immune system, or those unlucky enough to catch a particularly bad strain may be in imminent danger.
In order to minimize the threat of the flu on an annual basis, the Center for Disease Control suggests that everyone aged six months and older get the flu vaccine each year in advance of flu season.
The flu shot is a flu vaccine that contains a sample of live attenuated viruses, killed viruses, or virus components. When administered, these shots are intended to generate an immune response that is ideally strong enough to protect against the flu virus.
The flu vaccine is not, as the name implies, a single vaccine; instead, it is generally a combination a three to four different viral types, or strains. These various strains are combined based on expert analysis according to the most likely flu strains to spread during a given flu season. These are often based on the most prevalent strains in the previous flu season.
There has been significant hype surrounding the flu shot over the last several years, but the concept of an influenza vaccine is not new. The flu virus was discovered in 1933, with Jonas Salk and Thomas Francis creating the first flu vaccine five years later in 1938. While vaccines were available in the 1940s to 1960s, widescale vaccination was not explored until the 1970s, when around 25% of the population received injections to attempt to prevent a swine flu outbreak. Since this point, technology has improved, leading to more precise vaccinations and increased protection.
In some cases, individuals who receive the flu shot will feel ill shortly following the injection as a result of a reaction to the shot itself. Common symptoms include redness, tenderness, swelling, and soreness where the shot was administered, headache, low-grade fever, muscle aches, fever, cough, or runny nose. If these symptoms arise, they will usually occur within the first one to two days.
In some cases, more serious reactions may take place. These side effects are most likely to appear several minutes to hours after getting a flu shot and include anaphylactic reactions, wheezing, and dizziness. With treatment, these effects are unlikely to be life-threatening.
Regardless of the potential risks of side effects in getting the flu shot, the vaccine is always a better alternative than contracting the flu.
The flu shot has many significant advantages in society, working to protect both healthy and vulnerable populations from the potentially deadly effects of the flu. Annually, on average, the flu causes around 31 million outpatient visits, 200,000 hospitalizations, up to 50,000 deaths, and an economic burden of over $87 billion. In the 2017 to 2018 flu season, roughly 80,000 people died. The flu is not limited to the young or the elderly; around 60% of those who get the flu are between 18 and 64.
In the 2016 to 207 flu season, the vaccine prevented approximated 5.3 million cases of the flu, 2.6 million influenza-related medical visits, and 85,000 hospitalizations related to the flu. This reduces both the chances of loss of life as well as the economic consequences on the U.S. healthcare system as a whole. The flu vaccine also protects those who are more likely to be significantly affected; for example, pregnant women who receive the shot reduce their risk of hospitalization by 40%.
Numerous common myths accompany the flu and flu shots. Unfortunately, many of these fallacies contribute to a lack of education and a general disregard for flu shots.
While one flu shot is always better than no flu shots, getting the flu shot in past years is not adequate for the current year. Vaccines and expected flu trends vary from year to year, so the more shots received, the higher immunity will be overall. In addition, the immune response to the flu begins to fade in time, so a vaccine that was once effective will not necessarily continue to be effective.
In some ways, this is true. The flu shot does not guarantee immunity, and it is still possible to get the flu after receiving a vaccine. This largely happens when the selected strains for immunization in a particular flu season do not cover the most common form of flu virus in that flu season. For those who delay getting a flu shot, it is possible to contract the flu during the two week period the vaccine takes to create an immune defense.
However, it is far more likely that those who believe they have the flu actually have a rhinovirus or other contagious disease with similar symptoms. The flu vaccine is only intended to address influenza, not other common illnesses.
The flu shot does not work immediately. This is a common misconception; it takes approximately two weeks for the flu shot to generate adequate immune protection. As such, individuals are often encouraged to get the latest flu shot before the beginning of flu season. Flu season is considered to be from December to February, with immunizations generally becoming available in September to October. Patients at risk should get a flu shot as early as possible.
A strong immune system is not necessarily an adequate defense against the flu. Particularly severe cases can cause death in even young, healthy people.
While a flu shot is important for everyone healthy enough to receive it, those who are unable to get a flu shot must rely on the immunity of those who do. For individuals who work with the elderly, immunocompromised populations, pregnant women, infants, or any other vulnerable communities, the flu shot is vital.
The flu can be diagnosed in several ways, but doing so generally requires a visit to a medical professional. Some doctors will diagnose the flu based solely on symptoms, but for those hoping for a more precise result, several testing methods are available.
For on-site results, many physicians will rely on rapid influenza diagnostic tests (RIDTs) or rapid molecular assays. RIDTs can provide results in 10 to 15 minutes but are less accurate, while a rapid molecular assay tests the genetic material of a virus and provide results in 15 to 20 minutes. However, neither of these tests are as accurate as laboratory swab tests. These tests can utilize patient samples to provide a full and specific breakdown of a virus, offering clinically valuable results for patients, physicians, and researchers.
The flu can be a serious concern for individuals of all ages and levels of wellness. Accordingly, a flu shot is recommended for all eligible members of the population prior to the onset of each flu season in order to prevent the onset of influenza and all related risks.