How Long Does Flu Vaccine Work

Should You Get A Flu Vaccine

The flu vaccine: explained

Influenza is a viral infection. More commonly called the flu, this disease’s symptoms range from mild to severe. The flu can cause hospitalization or even death for people who are already frail. The severity of the flu differs from year to year.

Healthy people can be infected by the influenza virus and transmit it to others. But young children, elderly people, pregnant women, and people with certain medical conditions are at greater risk of suffering serious complications from the flu.

The best way to reduce the risk of catching the flu and spreading it to others is to receive an annual flu vaccine. Vaccines are available either as an injection or nasal spray. When more people in a community get the flu vaccine, the illness spreads to fewer people, and the whole community enjoys stronger immunity.

Q& a With Pharmacy Expert Hai Tran Pharmd

As the first cases of flu are reported in Los Angeles this season, public health experts are urging anyone who isn’t already vaccinated to get the flu shot. It’s the best protection against the flu, which could pummel the U.S. this winter after nearly disappearing last year.

“Getting vaccinated against the flu reduces your risk of becoming infected as well as your risk of being hospitalized with an infection or dying,” said clinical pharmacist Hai Tran, PharmD, associate director of Pharmacy at Cedars-Sinai. “You not only protect yourself but also those around you, and you are helping build the herd immunity that protects the most vulnerable people in our community.”

With everyone paying more attention to how vaccines work during the ongoing COVID-19 pandemic, the Cedars-Sinai Newsroom interviewed Tran to get a closer look at the flu vaccine. It’s easy to take this long-established tool for granted, but a lot of work throughout the year goes into developing a new formulation of the shot each season.

We spoke with Tran for more details on the flu shot’s origins, how it works and how it’s developed each year.

How Effective Is The Flu Vaccine

The flu vaccine gives the best protection against flu.

Flu vaccines help protect against the main types of flu viruses, although there’s still a chance you might get flu.

If you do get flu after vaccination, it’s likely to be milder and not last as long.

Having the flu vaccine will also stop you spreading flu to other people who may be more at risk of serious problems from flu.

It can take 10 to 14 days for the flu vaccine to work.

When Is The Most Effective Time To Have The Flu Shot

Studies show that the best time to have your flu vaccination is three to four months after it is administered. This is when the flu vaccination is most effective in your body so this needs to be taken into account in light of the peak of flu season in order to get the timing of your vaccine right. Generally the flu season in Australia spans June through September, with its peak in August so factoring in a vaccination in late April or early May would probably be the best timing for the majority of the population.

Its also worth noting that even though the flu does have a seasonal peak, it is possible to contract it at any time of the year. The flu vaccination provides you with the most enduring protection and can reduce the severity of your symptoms if you do develop the virus.

Can A Flu Vaccine Give Me Flu

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No, a flu vaccine cannot cause flu illness. Flu vaccines that are administered with a needle are currently made in two ways: the vaccine is made either with a) flu vaccine viruses that have been killed and are therefore not infectious, or b) with proteins from a flu vaccine virus instead of flu vaccine viruses . Nasal spray vaccine is made with attenuated live flu viruses, and also cannot cause flu illness. The weakened viruses are cold-adapted, which means they are designed to only cause infection at the cooler temperatures found within the nose. The viruses cannot infect the lungs or other areas where warmer temperatures exist.

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Allergic Reactions To The Flu Vaccine

It’s very rare for anyone to have a serious allergic reaction to the flu vaccine. If this does happen, it usually happens within minutes.

The person who vaccinates you will be trained to deal with allergic reactions and treat them immediately.

Anyone can report a suspected side effect of a vaccine through the Yellow Card Scheme.

Cold Vs Flu: What Is The Difference

The common cold and the flu are often confused due to their similar symptoms. But the CDC notes one main difference between the two: The cold and the flu are caused by two different types of viruses.In general, the symptoms of the flu are more severe and more common. Colds are typically milder. People with colds are more likely to have a runny or stuffy nose than those with the flu. They are also much less likely to experience serious complications requiring hospitalization, such as pneumonia or bacterial infections.

When Does The Flu Vaccine Start To Work

The flu shot gets to work in your body about two weeks after you have been given the vaccine. This is when your body starts to produce the antibodies required to fight the virus.

Remember that you are still susceptible to developing the flu during this period and you should still practice good hygiene in the interim period.

Good hygiene practices that may protect you against contracting the flu include:

Avoid touching your mouth and nose unnecessarily
Use hand steriliser
Avoid big crowds and practice social distancing when you do need to congregate with groups of people

What Side Effects Can Occur After Getting A Flu Vaccine

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While a flu vaccine cannot give you flu illness, there are different side effects that may be associated with getting a flu shot or a nasal spray flu vaccine. These side effects are mild and short-lasting, especially when compared to symptoms of bad case of flu.

A flu shot: The viruses in a flu shot are killed , so you cannot get flu from a flu shot. Some minor side effects that may occur are:

Soreness, redness, and/or swelling where the shot was given
Headache
Nausea

Fatigue

The nasal spray: The viruses in the nasal spray vaccine are weakened and do not cause severe symptoms often associated with influenza illness. In children, side effects from the nasal spray may include:

Runny nose

In adults, side effects from the nasal spray vaccine may include:
Runny nose

Sore throat
Cough
If these problems occur, they begin soon after vaccination and usually are mild and short-lived. A flu shot, like other injections, can occasionally cause fainting. Tell your provider if you feel dizzy or have vision changes or ringing in the ears. As with any medicine, there is a very remote chance of a vaccine causing a severe allergic reaction, other serious injury, or death.

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Is The Flu Shot Necessary

You are by no means forced to get a flu shot. However, health professionals highly recommend it. A common misconception, particularly among those ages 18 49, is that you dont need a flu shot. Studies have found this age group is the least likely to get vaccinated. Those ages 65 and older are the most likely to get their flu shot.Influenza vaccination is important even for healthy people, Thomas says. Many people think the flu is a minor illness. However, even a healthy young person can have a severe reaction to this infection. When sick or elderly people get the flu, they may die of additional complications, such as bacterial pneumonia.

Influenza vaccination is important even for healthy people.

Anyone, even those with strong immune systems, can get the flu. Even if you think dont need a flu shot, getting one can help prevent you from transmitting the flu to others. The more citizens who get their flu shot, the less risk there is for the entire community.

How To Get Vaccinated Against Influenza

Influenza vaccines are given as an injection, usually in the upper arm. It is important to get the right vaccine for your age. Your immunisation provider can tell you which vaccine they will use for you or your child’s influenza immunisation.

Influenza vaccines available under the NIP for the 2022 season include:

VaxiGrip Tetra

The Therapeutic Goods Administration website provides product information and consumer medicine information for each vaccine available.

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Flu Vaccine For Frontline Health And Social Care Workers

If you’re a frontline health and social care worker, your employer should offer you a flu vaccine. They may give the vaccine at your workplace.

You can also have an NHS flu vaccine at a GP surgery or a pharmacy if:

you’re a health or social care worker employed by a registered residential care or nursing home, registered homecare organisation or a hospice
you work in NHS primary care and have direct contact with patients this includes contractors, non-clinical staff and locums
you provide health or social care through direct payments or personal health budgets, or both

Advances In Flu Vaccination

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Research is ongoing to find a universal flu vaccine that will be effective against all strains. This could eliminate the need to develop a new vaccine each year, or even allow people to get the vaccination less often than yearly. While an exciting prospect, science just isn’t there yet.

What science has proven, however, is the effectiveness of flu vaccination. Despite the aforementioned shortcomings, getting a flu shot is still the most effective way to prevent against infection.

The traditional way the vaccine is manufactured is by inoculating fertilized chicken eggs with the chosen viral strains. After a few days, fluid from the eggs is harvested and purified to make the vaccine. Both inactivated influenza vaccine and live attenuated influenza vaccine are made in this way. However, some influenza viruses, such as the H3N2 viruses, grow poorly in chicken eggs.

A process was approved in 2012 to allow growing the virus on cell cultures. This results in an egg-free vaccine that is safer for people who are severely allergic to eggs. A recombinant process was approved in 2013. As of the 2019 to 2020 flu season, only one influenza vaccine is produced this way in the U.S.

These are considered two significant advances. There are also developments in making vaccines for special populations and circumstances.

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When To Get The Influenza Vaccine

New season influenza vaccines under the NIP are expected to be available from April. Timing may be different for your local area. Check with your immunisation provider to find out when they will have the vaccine available and when you will be able to book in to have the vaccine.

Annual influenza vaccine should occur anytime from April onwards to be protected for the peak flu season, which is generally June to September. The highest level of protection occurs in the first 3 to 4 months following vaccination.

However, it is never too late to vaccinate since influenza can circulate in the community all year round.

Pregnant women should receive the vaccine at any stage during pregnancy.

Influenza vaccines can be given on the same day with a COVID-19 vaccine.

How Is The Flu Shot Made

Tran: Vaccine developers use three different types of processes to make flu shots.

Currently, most influenza vaccines are made using an egg-based process. Manufacturers use a fertilized chicken egg to grow whichever four strains of the virus the U.S. Food and Drug Administration decides will be dominant during the upcoming flu season. Manufacturers incubate the egg, allowing the virus to replicate, harvest the virus and then deactivate or weaken it before adding it to a mass-produced injection. A second method uses an animal cell instead of egg cells.

The third process isolates the genes that have the instructions for making the target protein that your body’s immune system must identify. Those genes are combined with a different virus that infects invertebrates, such as worms and helps pass the genetic instructions to a host cell. These proteins are grown in bulk, purified and become so-called recombinant vaccines.

What Is The Cell

The production of influenza vaccines traditionally involves hens eggs. However, there is a different method for cell-based influenza vaccines such as Flucelvax Quad, the only cell-based flu vaccine approved for use in Australia. Its approved for use in people aged 9 years and older but has not been added to the National Immunisation Program schedule.

Studies show that cell-based vaccines have a similar efficacy and safety profile to standard flu vaccines. Normally, neither type is recommended over the other.

However, standard flu vaccines are preferred for use in pregnancy because a large body of evidence supports their safety for pregnant women. The safety of cell-based flu vaccines during pregnancy hasnt been assessed.

Can I Get The Flu Vaccine If I Have An Egg Allergy

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The influenza vaccine is typically grown in eggs. But the traces of egg protein that remain after the vaccine is made are so tiny that the Australasian Society of Clinical Immunology and Allergy says both adults and children with egg allergy can be safely vaccinated against the flu. The risk of anaphylaxis after vaccination is very low, estimated at 1.35 cases per 1 million doses.

It is rare for people with egg allergy to experience other side effects, such as hives, wheezing, vomiting or abdominal pain, after getting the flu shot. If you are concerned, ask your doctor if you, or your child, can be observed by staff for 30 minutes after receiving the vaccine .

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How Long Does The Flu Last

Unfortunately, the flu can stick around for a while. Some people may get better within a few days, but the flu can last up to two weeks. Although its disruptive to your daily routine, you should stay home and away from people except to go to the doctor until you get better in order to avoid spreading it to others: about 24 hours after your fever goes away without fever-reducing meds. Youll be contagious from about 1 day before showing symptoms to 5 to 7 days after.

When Should I Get The Flu Jab

Using the recommendations from the WHO, the vaccine goes into production in March and usually becomes available in the UK from September. Every year, the timing of the onset and peak of the flu season changes making it hard to pinpoint the exact moment when its best to have the flu jab. According to the NHS, people should aim to have the flu vaccine during October or November, although its not a problem if you get the jab later in winter.

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How Does The Flu Vaccine Work

Q& A With Pharmacy Expert Hai Tran, PharmD

Hai Tran, PharmD

Newswise Los Angeles –“Getting vaccinated against the flu reduces your risk of becoming infected as well as your risk of being hospitalized with an infection or dying,” said clinical pharmacist Hai Tran, PharmD, associate director of Pharmacy at Cedars-Sinai. “You not only protect yourself but also those around you, and you are helping build the herd immunity that protects the most vulnerable people in our community.”

We spoke with Tran for more details on the flu shot’s origins, how it works and how it’s developed each year.

Flu Strains Chosen For The Vaccine

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Influenza viruses are constantly changing. Because of this, the influenza strains that were common during last years flu season may not be as prevalent for the current flu season.

Early each year, scientists meet to select the strains to include in the flu vaccine for countries in the northern hemisphere, including the United States. These meetings are held early in the year because vaccine producers need time to make the vaccine so its ready for the beginning of the flu season in the fall.

Vaccine strains are chosen based on what current surveillance data predicts may be the most common strains for the upcoming flu season. However, sometimes the selected strains dont match well with the strains that actually end up being most prevalent during a flu season.

When this happens, vaccine effectiveness can be low. However, if the strains selected are a good match, vaccine effectiveness is higher.

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What Are Your Chances Of Developing The Flu If You Have Been Vaccinated

The flu vaccination protects around five to six adults out of every ten from flu viruses. It also makes you more likely to have a milder version of the flu in the event that you develop it. So while there is no guarantee that you wont get it, statistically it is a good idea and you will have added protection against flu viruses if you are vaccinated.

If you are allergic to any of the ingredients in the vaccine or if you have already contracted the flu, you would not need to be vaccinated.

The government has made it easy for most people to be vaccinated against the flu by making a number of free vaccines available to vulnerable groups. The shot takes a few minutes to administer and most people do not experience any side effects.

To find out more about how long does the flu shot last and how you can protect yourself and your wider community, please book an appointment with us: .