Flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. Every flu season is different, and flu can affect people differently, but during typical flu seasons, millions of people get flu, hundreds of thousands of people are hospitalized and thousands to tens of thousands of people die from flu-related causes.
The best way to prevent flu is by getting a flu vaccine each year. Flu vaccines cause antibodies to develop in the body about two weeks after vaccination. These antibodies protect against flu illness. Seasonal flu vaccines are designed to protect against the influenza viruses that research indicates will be most common during the upcoming season. All flu vaccines in the United States are “quadrivalent” vaccines, which means they protect against four different flu viruses: an influenza A (H1N1) virus, an influenza A (H3N2) virus, and two influenza B viruses.
However, flu vaccines are not perfect. They are not always effective against all strains of the flu virus, and their effectiveness can vary from season to season and from person to person. Flu viruses are constantly changing and evolving, and sometimes new variants emerge that are not well matched by the current vaccines. This can reduce the protection that the vaccines offer. Moreover, flu vaccines are made using a complex and time-consuming process that involves chicken eggs, cell cultures, or recombinant technology. This process can introduce errors, mutations, or delays that can affect the quality and quantity of the vaccines.
Therefore, many scientists are working on finding a better way of making a flu vaccine. One of the main goals is to develop a universal flu vaccine, which would provide long-lasting and broad protection against all types of flu viruses, including new and emerging ones. A universal flu vaccine would not need to be updated or reformulated every year, and would not depend on the accuracy of predicting the circulating strains. A universal flu vaccine would also use better technology than the current methods, which are outdated and inefficient.
Several approaches and strategies are being explored to create a universal flu vaccine. Some of them are:
- Targeting the conserved parts of the flu virus, such as the stem of the hemagglutinin (HA) protein, which is essential for the virus to enter the host cells. The HA protein has a head and a stem, and the head is the part that changes frequently and is recognized by the current vaccines. The stem, however, is more stable and similar across different flu viruses. By inducing antibodies against the stem, a universal flu vaccine could prevent the virus from infecting the cells, regardless of the head variation.
- Using nanoparticles or virus-like particles (VLPs) to display multiple copies of the flu antigens, such as the HA or the neuraminidase (NA) proteins, on their surface. Nanoparticles or VLPs are tiny structures that mimic the shape and size of the flu virus but do not contain any genetic material or cause infection. By presenting the flu antigens in a multivalent and repetitive manner, a universal flu vaccine could elicit a stronger and broader immune response than the current vaccines, which only display one or two copies of the antigens.
- Using mRNA technology to deliver the genetic instructions for the flu antigens to the host cells, which would then produce and present the antigens to the immune system. mRNA technology is the same technology that is used by the COVID-19 vaccines developed by Pfizer-BioNTech and Moderna. mRNA vaccines have several advantages over the current flu vaccines, such as being faster and easier to produce, being more adaptable and flexible to new strains, and being more potent and durable.
These are some of the examples of the ongoing research and development of a better way of making a flu vaccine. However, none of these approaches have been proven to be safe and effective in humans yet, and there are still many challenges and obstacles to overcome. A universal flu vaccine is not likely to be available shortly, and it may not be able to replace the current flu vaccines completely. Therefore, it is still important to get the seasonal flu vaccine every year, as it is the best way to prevent flu and its complications.
List of facts and figures related to a flu vaccine
- Flu vaccination has been shown to have many benefits, including reducing the risk of flu illnesses, hospitalizations, and deaths. For example, during 2019-2020, the last flu season prior to the COVID-19 pandemic, flu vaccination prevented an estimated 7 million influenza illnesses, 3 million influenza-associated medical visits, 100,000 influenza-associated hospitalizations, and 7,000 influenza-associated deaths.
- Flu vaccination can also reduce the severity of flu illness among people who get sick. A 2017 study showed that flu vaccination reduced deaths, intensive care unit (ICU) admissions, ICU length of stay, and overall duration of hospitalization among hospitalized flu patients.
- Flu vaccination can also protect people around you who are more vulnerable to serious flu illness, such as babies, young children, older people, and people with certain chronic health conditions.
- Flu vaccines are safe and have a good safety record. The most common side effects are mild and short-lasting, such as soreness, redness, or swelling at the injection site. Serious allergic reactions to flu vaccines are very rare.
- Flu vaccines do not cause flu. The viruses in the flu vaccine are either killed or weakened and cannot give you the flu. Some people may experience flu-like symptoms, such as fever, headache, or muscle aches, after getting the flu vaccine, but these are not caused by the flu vaccine and are usually mild and short-lasting.
- Flu vaccines are recommended for everyone 6 months of age and older, with rare exceptions. People who have had a severe allergic reaction to a flu vaccine or any of its ingredients should not get the flu vaccine. People who have a moderate to severe illness with or without a fever should wait until they recover before getting the flu vaccine. People who have a history of Guillain-Barré syndrome (GBS) should talk to their doctor before getting the flu vaccine.
- Flu vaccines are available in different types and formulations, depending on the age, health status, and preference of the person. Some of the options include standard-dose flu shots, high-dose flu shots, adjuvanted flu shots, recombinant flu shots, and nasal spray flu vaccine. Different vaccines are licensed for use in different age groups, and some vaccines are not recommended for some groups of people.
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: Flu Vaccine Safety Information | CDC : Misconceptions about Seasonal Flu and Flu Vaccines | CDC : Who Needs a Flu Vaccine and When | CDC : Different Types of Flu Vaccines | CDC