Everyone 6 Months And Older Should Get The Flu Shot
The flu shot is your best defence against the flu. The flu shot is recommended for everyone 6 months of age and older.
It can save lives by:
- protecting you, if you’re exposed to the virus
- preventing you from getting very sick
- protecting people close to you:
- because you’re less likely to spread the virus
- who are at higher risk of serious flu complications if they get the flu
The flu shot wont protect you against COVID-19.
Are There Side Effects
Possible side effects vary between the flu shot and the nasal vaccine. The most typical side effect of the shot involves a local skin reaction. The skin immediately surrounding the shot area may swell, ache, redden, and become tender. This reaction typically clears up in one to two days.
Did the Flu Shot Cause My Illness?
It’s not likely. Studies comparing people who took the flu shot with people who took a placebo showed no difference as far as who developed symptoms like fever, runny nose, and body aches. Some people who receive the shot have been or will be infected by a common cold virus or some other illness. Also, some people are infected with flu before the shot has become fully effective .
Side Effects of the Nasal Spray Flu Vaccine
The nasal spray flu vaccine may cause side effects different from the injection, including vomiting, fever, and headache, as well as common cold symptoms like runny nose and sore throat. When these occur, they are usually much less severe than comparable symptoms found during a flu infection.
Serious Side Effects
Allergic reactions are the most serious side effects of flu vaccination. They are very rare. Anaphylactic reactions can be fatal, but they can also be effectively treated. The CDC recommends flu shots even for those with known egg allergies, provided these patients are monitored following the injection.
How Long Did It Take To Develop The Flu Vaccine
- The first flu vaccine was licensed for civilian use in the U.S. in 1945.
- Dr. Jonas Salk was one of the lead researchers.
- Nearly 200 million doses of vaccine were expected to be manufactured this flu season.
The 1918 influenza pandemic infected an estimated 500 million people worldwide and left 675,000 people dead in the United States, according to the CDC.
But it wasn’t until 1945 – nearly three decades later – that the first flu vaccine was licensed for civilian use in the U.S.
In contrast, an effective and safe COVID-19 vaccine was developed in less than a year. Historically, vaccines have taken years to make it to distribution.
The first-ever vaccine to be developed was for smallpox in 1796, according to the World Health Organization.
Today, vaccines are available for more than two dozen diseases. Many of the shots, like those for measles and chickenpox, are considered routine.
Scientists dedicate their entire careers to researching vaccines. Dr. Jonas Salk, famous for creating the polio vaccine in the 1950s, was one of the lead researchers on the flu vaccine a decade earlier. Before Salk died at age 80 in 1995, he worked on a vaccine for HIV, which still hasn’t come to fruition.
Since Salk’s early work on the flu vaccine, it’s become one of the most common shots given.
Here’s a look back at some of the key moments in the history of influenza and the flu vaccine, based on a timeline from the U.S. Centers for Disease Control and Prevention:
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Why Do Kids Need Two Flu Shots
Babies under 2 and children who have never received the flu shot before need two doses of the flu shotadministered about four weeks apartbecause they are less likely to have come in contact with the virus. The first shot primes their little immune systems, while the second helps them develop flu-fighting antibodies.
Why We Need New Flu Vaccines Every Year

There are several reasons a new flu vaccine must be made each year.
Flu viruses can change from year to year, so the vaccine is updated to protect against new virus strains that are expected to circulate in the U.S. The vaccine needs to include influenza virus strains that most closely match those in circulation for the influenza season. In addition, the protection provided by the flu vaccine a person received in the previous year will diminish over time and may be too low to prevent influenza disease into next years flu season.
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What Are Indications For Flu Vaccines
The CDC recommends that anyone over 6 months of age be vaccinated against the flu. This is particularly important for certain people, including those who are at high risk of having serious seasonal flu-related complications or people who live with or care for those at high risk for serious seasonal flu-related complications. During flu seasons when vaccine supplies are limited or delayed, the Advisory Committee on Immunization Practices makes recommendations regarding priority groups for vaccination. The most recent ACIP recommendations presented by the CDC for 2020-2021 are as follows:
There is a high-dose IM vaccine for people 65 and older .
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The Eighties: Subunit Vaccines
In 1980, the first subunit vaccines were licensed in the United Kingdom and are currently available in several countries worldwide.
In 1978, as a result of a major mutation, a new virus strain, H1N1, appeared on the global epidemiological scene. This strain, which was similar to a virus circulating in 1958, emerged in Russia and began to co-circulate, either simultaneously or alternately, with the previous one .
Antigenic drift, caused by frequent changes in the composition of the virus, determined the need to update the vaccine composition each year. This necessity prompted both the implementation of the first surveillance systems and the production of the first trivalent vaccine, which included three formulation strains , in order to ensure effective protection during the 1978 pandemic.
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Is It Ok To Get The Flu Vaccine More Than Once In The Same Flu Season
Studies have not shown there is any benefit for most adults getting more than one dose of vaccine in the same flu season. However, its recommended that some people get 2 doses of the flu vaccine in one season:
- children under 9 years old who have not ever been vaccinated against the flu
- people who are having flu vaccination for the first time after a stem cell transplant or organ transplant
- pregnant women, who may be vaccinated with the next seasons influenza vaccine if it becomes available in the latter part of their pregnancy, even if they had the previous seasons vaccine
- overseas travellers who are going to the northern hemisphere winter
A Flu Vaccine Is The Best Prevention
Flu seasons and their severity are unpredictable. Annual vaccination is the best way to prevent influenza in people ages 6 months and older.
An annual vaccination to prevent flu is the best way to reduce the risk of getting the flu and spreading it to others. When more people get vaccinated, it is less likely that the flu viruses will spread through a community.
The vaccine typically changes each year and contains the four flu virus strains that are expected to circulate in the U.S. during the upcoming flu season. The effectiveness of influenza vaccines varies depending on several factors, such as the age and health of the recipient, the types of circulating influenza viruses, and the degree of similarity between circulating viruses and those included in the vaccine.
The task of producing a new vaccine for the next flu season starts well before the current season ends. For the FDA, its a year-round initiative.
The flu vaccine will trigger your immune system to produce antibodies to protect against influenza disease it will not make you sick with the flu. It can take about two weeks after vaccination for antibodies to develop in the body, which is an important reason to get your flu vaccine early, before flu activity starts.
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Who Is Most At Risk
Complications from the flu can include serious conditions, like pneumonia or heart attacks and, in some cases, death. Flu causes about 12,200 hospitalizations and 3,500 deaths in Canada each year.
Some people are more vulnerable to complications and hospitalization from the flu:
- babies under 6 months old are too young to get the flu shot, but they’ll get some protection if their parent got the flu shot while they were pregnant
- children under 5 years of age, because their immune systems are developing, and their airways are small and more easily blocked
- people 65 years old and older, because their immune systems are weaker and they are more likely to have an underlying condition that increases their risk
- pregnant people, because their immune system, heart and lungs change especially later in pregnancy making them more likely to get seriously ill from the flu
- people with underlying health conditions, such as asthma, heart disease or diabetes
Final Thoughts On Flu Shots For Babies
Unfortunately, influenza is a pretty sneaky infection. You can still catch it even after getting the vaccine, but the illness will likely be less intense than if you didnt get the shot. And, by getting the shot, youll be helping protect your friends and neighborsespecially those struggling with serious illnessesby doing your part to build to your communitys herd immunity.
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What Is The History Of Flu Vaccine Development
In 1933, researchers discovered that viruses cause influenza . Prior to 1933, people thought a bacterium named Haemophilus influenzae caused the flu. In 1938, Jonas Salk and Thomas Francis developed the first vaccine against flu viruses. This first flu vaccine protected the U.S. military forces against the flu during World War II. Dr. Salk used his experience with influenza vaccine to develop an effective polio vaccine in 1952. Vaccines produced from the 1940s to the 1960s were not as purified as more modern vaccines, and the impurities in vaccines were thought to contribute to side effects such as fever, aches, and fatigue. Since these symptoms were similar to those that accompanied the flu , people mistakenly thought they got the flu from the vaccination. However, they did not get the flu from the vaccines since the vaccines used killed virus.
Because of the potential for widespread infection, life-threatening complications, and deaths that the H1N1 pandemic virus strain seemed to possess, health researchers accelerated the H1N1 tests so that the vaccine could be provided before the usual six-month timeline. However, all of the steps were done in the same way as for seasonal vaccines but over a shorter period with fewer people involved in the initial trials. Tested and approved H1N1 vaccine started to become available in late September 2009 and in October 2009 in the Americas and Asia.
Children Who Shouldnt Have The Vaccination

Children may not be able to have the nasal vaccine if they:
- are currently wheezy or have been wheezy in the past 72 hours, they should be offered a suitable injected flu vaccine to avoid a delay in protection
- have needed intensive care due to asthma or egg allergic anaphylaxis
- have a condition, or are on treatment, that severely weakens their immune system or have someone in their household who needs isolation because they are severely immunosuppressed
- are allergic to any other components of the vaccine
- have a condition that needs salicylate treatment
Also, children who have been vaccinated with the nasal spray should avoid close contact with people with very severely weakened immune systems for around 2 weeks following vaccination because theres an extremely remote chance that the vaccine virus may be passed to them.
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The Vaccine And The Future
The current conventional flu vaccine and its potential to protect people and save lives is constantly being developed, and work is far from complete. The effectiveness of the vaccine varies enormously each year, from just 3% up to 70%.
In 2009, the world saw the first outbreak of a Pandemic Influenza virus this century. Such new viruses occur when the virus juggles its genes with those of another virus in a different animal, and then humans are exposed to a virus never seen before.
Each year, however, the virus also changes slowly. Unlike a Pandemic Influenza virus that appears from nowhere, these yearly viruses are caused by slow and subtle changes. Because of these viruses that drift each year, we need to have a new vaccine.
This year, with Aussie Flu, we have seen that influenza can catch us unprepared. We know that the virus has drifted slightly from that which is in the vaccine. The yearly vaccine is not perfect, it relies on a judgement that locks down the vaccine, but in the months that follow the virus can change.
In addition, we have had Japanese Flu this was a B virus. In many countries, the yearly vaccine did not contain a killed virus that protected against that strain, hence we now read many reports of Japanese Flu.
Other Methods Of Manufacture
Methods of vaccine generation that bypass the need for eggs include the construction of influenza virus-like particles . VLP resemble viruses, but there is no need for inactivation, as they do not include viral coding elements, but merely present antigens in a similar manner to a virion. Some methods of producing VLP include cultures of Spodoptera frugiperdaSf9 insect cells and plant-based vaccine production . There is evidence that some VLPs elicit antibodies that recognize a broader panel of antigenically distinct viral isolates compared to other vaccines in the hemagglutination-inhibition assay .
A gene-based DNA vaccine, used to prime the immune system after boosting with an inactivated H5N1 vaccine, underwent clinical trials in 2011.
On November 20, 2012, Novartis received FDA approval for the first cell-culture vaccine. In 2013, the recombinant influenza vaccine, Flublok, was approved for use in the United States.
On September 17, 2020, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for Supemtek, a quadrivalent influenza vaccine . The applicant for this medicinal product is Sanofi Pasteur. Supemtek was approved for medical use in the European Union in November 2020.
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Side Effects Of Boosters
You may experience some side effects, similar to those you mightve had after the first or second dose, such as muscle aches, pain at the injection site or headaches.
For most people these are mild effects. They are a sign your bodys immune system is learning to fight the virus. They dont last long and for many people do not impact on day-to-day activities.
How Does Influenza Spread
Influenza spreads easily from person to person through coughing, sneezing or having face-to-face contact. The virus can also spread when a person touches tiny droplets from the cough or sneeze of an infected person or object and then touches their own eyes, mouth or nose before washing their hands.
Symptoms can begin about 1 to 4 days, or an average of 2 days, after a person is first exposed to the influenza virus. Fever and other symptoms usually last 7 to 10 days, but the cough and weakness may last 1 to 2 weeks longer.
An infected person can spread the influenza virus even before feeling sick. An adult can spread the virus from about 1 day before to 5 days after symptoms start. Young children and people with weakened immune systems may be able to spread the virus for a longer period of time.
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Flu Vaccines Are Very Safe
Flu vaccines have a good safety record. Hundreds of millions of Americans have safely received flu vaccines for more than 50 years, and there has been extensive research supporting the safety of flu vaccines.
Vaccines, like any medicine, can have side effects. When they occur, flu vaccine side effects are generally mild and go away on their own within a few days.
Available Vaccines And Vaccination Campaigns
Because new strains of influenza appear frequently, the seasonal flu vaccine usually changes each year. Each season vaccine is generally designed to protect against three strains of influenza: two A strains, and one B strain. From start to finishthe selection of which three strains to target with the vaccine, to the production of the final productthe development process for the seasonal flu vaccine can take up to eight months.
Influenza surveillance centers around the world monitor the circulating influenza strains for trends year-round. Genetic data is collected and new mutations are identified. The World Health Organization is then responsible for selecting three strains most likely to genetically resemble strains circulating in the coming winter flu season. For the northern hemisphere winter, this decision is made in the February prior. In some cases, one of the strains used in the previous years vaccine may be chosen again, if that strain continues to circulate. From this point, the development and production of the vaccine can begin.
Four to five months after the three vaccine strains have been selected , the three vaccine strains that have been developed are separately tested for purity and potency. Only after individual testing is completed are the three strains combined into a single seasonal vaccine.
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