The Flu Vaccine Contains Several Viral Strains
The CVVs are mostly grown and cultivated in either fertilized hen eggs or egg-free cell cultures.
No matter the year, the flu vaccine is designed to protect against three to four flu viruses in circulation. That’s because there are different types of flu caused by different viral strains.
The most common are flu types A and B, which is why each year the flu vaccine contains strains of both types A and B viruses. For example, the vaccine for the 2019-20 flu season in the US contains strains of H1N1 and H3N2 which both cause flu type A and two flu type B strains, called B/Victoria and B/Yamagata.
Getting all those different viruses to coexist in one place is where the hen eggs and cell cultures come in.
Each viral strain is either injected into an egg or added to cell culture. Then the viruses are given a few days to replicate and grow, just as if they were inside a person.
All the while, the eggs and cultures are handled under sterilized conditions. For instance, the egg yolks are inoculated with viruses under ultraviolet light and in an area absent of dust and other contaminants.
After a few days, the eggs and cultures are teaming with flu viruses, which means it’s time to extract them. After extraction, those viruses are then killed or weakened for the vaccine, at which point a small number of stabilizers and preservatives are added to prevent contamination and keep the vaccine stable after manufacturing.
Flu Shot Side Effects : What’s Normal And What’s Cause For Concern
All vaccines have the potential to cause side effects, and that includes your yearly flu shot. But most are totally normal.
The coronavirus is still a very real concern this fall, but so is the influenza virus, aka the flu. The good news is we have very safe and effective tools for fighting and preventing both potentially deadly viruses, thanks to the COVID-19 vaccines and the flu vaccine.
According to the CDC, flu shots are safe and one of the best ways to keep from getting and spreading the flu to others. And people who get vaccinated and get sick anyway often experience less severe symptoms. If you’re thinking of getting vaccinated for both COVID-19 and the flu, the CDC says it is safe to get both vaccines together .
The simple fact is, flu vaccines can save lives. There are plenty of myths out there about the flu vaccine, such as the idea that it can give you the flu. While that’s not true, you can experience some side effects from the flu shot. The side effects are usually mild and nothing to worry about, but it’s important to know about them so you’re not worried when you get your vaccine.
Below, Dr. Carmen Teague, specialty medical director at Atrium Health‘s Mecklenburg Medical Group shares what you need to know about common flu shot side effects that are normal, and which side effects may be a sign of something more serious.
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What Is The Difference Between An Epidemic And A Pandemic
Influenza epidemics occur every year. An epidemic does not affect all people because many people have at least some immunity. On the other hand, when new strains emerge, people do not have immunity, and, therefore, almost everyone is susceptible.
Flu pandemics occur about three times every century. Pandemics have occurred in 1889, 1900, 1918, 1957, 1968, and 2009. The pandemics in 1957 and 1968 each claimed four to six million lives, but the pandemic in 1918 was the most devastating. Between 50 and 100 million people died from the strain of influenza known as “Spanish flu” during that pandemic.
Watch this video clip related to making a vaccine in advance of the arrival of influenza during the fall 1968 pandemic. The clip is from the award-winning documentary, Hilleman: A Perilous Quest to Save the Worlds Children.
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When Is The Best Time To Get The Influenza Vaccine
Influenza season can start as early as the fall, so the American Academy of Pediatrics and the Centers for Disease Control and Prevention recommend receiving the influenza vaccine in September or October. Because it takes about two weeks after receiving the vaccine to be fully protected, its important to get the vaccine early during the fall. Only a few groups of people should be offered the influenza vaccine in August if it is available. These include:
- Women who are in their third trimester, so their baby can benefit from maternal antibodies before it is old enough to get vaccinated.
- Young children, particularly those who require two doses.
Some people are at increased risk of experiencing complications and as such, it is particularly important for them to get the influenza vaccine, including young children, pregnant women, adults 65 years of age and older, and individuals with underlying medical conditions, such as chronic heart, lung and kidney conditions.
Considerations For Getting A Covid
Its safe for your health care provider to administer a COVID-19 vaccine at the same time as other vaccines. If youre 12 years of age or older, you may get the flu shot at the same time as a COVID-19 vaccine. You may also get it any time before or after you receive the flu shot.
For children aged 5 to 11, the National Advisory Council on Immunization recommends a 14-day interval between a COVID-19 vaccine and other vaccines. This is to help better monitor for possible side effects from COVID-19 vaccines. Provinces and territories will decide on an interval for this age group as part of their vaccination programs.
Talk to a health care provider or consult your provincial or territorial public health authority for the latest guidance.
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The Sixties: Split Vaccines
New inactivated compounds were tested for safety and efficacy during seasonal epidemics in the 1960s, in particular two new formulations were created: split and subunit vaccines. The 1968 pandemic led to the development of trivalent inactivated vaccines against influenza viruses moreover the development of new split or subunit vaccines led to a decrease of adverse reactions in children. These vaccines were split using ether and/or detergent, and haemagglutinin and neuraminidase were, in the case of subunit vaccines, purified and enriched .
In the same period, the first flu vaccines were licensed in Europe, while in the US annual influenza vaccination was recommended for individuals at major risk of influenza complications.
In 1968, the new virus strain H3N2 appeared, completely replacing the previous type A strain , and led to another global pandemic with high morbidity and mortality . In the same year, a new type of vaccine, the split vaccine, was authorized in the US after several clinical studies had demonstrated that it was less reactogenic than whole virus vaccines, especially in the early years of life .
Safety And Side Effects
The inactivated flu vaccine does not contain the live virus and cannot cause flu. Flu vaccines have a very good safety record. The most commonly reported side effects of flu vaccines are:
- pain, swelling, bruising, hardness or redness at the injection site
- slightly raised temperature
- feeling generally unwell
A higher rate of these common side effects has been reported with Fluad, an adjuvanted trivalent vaccine which was recommended for people aged 65 and over in previous years. This year, Fluad Tetra is being offered to people aged over 65, which also uses an adjuvant. Side effects usually last 1-2 days.
There are several different makes of flu vaccine available each year. For more information on side effects, ask for the Patient Information Leaflet for the vaccine you are offered. Additional information about vaccine side effects, anaphylaxis and adverse reactions can be found here.
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Symptoms And Causative Agent
Influenza is a respiratory illness caused by influenza viruses. There are two main types of influenza viruses but many different strains of each type. The diseases caused by these viruses are often collectively referred to simply as the flu.
Illness from influenza can range from mild to very severe depending on several factors, including the viral strain, the patients age, and the patients health. Certain groups are at higher risk for serious complications from the flu.
Symptoms of the flu tend to emerge suddenly and include fever, chills, coughing, sore throat, achiness, headaches, and fatigue. Vomiting and diarrhea may also occur, but these symptoms are more common for children than for adults.
When Was The Flu Vaccine Invented
The very first monovalent flu vaccine was invented in 1938 and was widely used to inoculate United States defence forces during World War 2. The first bivalent influenza vaccine was developed in 1942 as a response to the discovery of Influenza Type B. In 1978, the first trivalent flu vaccine was introduced. This vaccine typically includes two influenza A strains and one influenza B strain.
In 2012, the first quadrivalent flu vaccine was licensed in the United States. Since then, a variant of the quadrivalent vaccine has become commonly recommended by WHO each year.
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Does The Influenza Vaccine Cause Guillain
The data have been mixed regarding whether influenza vaccine can cause Guillain-Barré syndrome however, it is now generally agreed that very rarely, people can get GBS after receiving the influenza vaccine. However, people can also experience GBS after viral infections, including influenza, and the rates of GBS are about 17 times higher after infection than vaccination. For more information about GBS, see the September 2021 Parents PACK Feature Article, Guillain-Barré Syndrome & Vaccines: The Risks and Recommendations.
Every year, between 75 and 150 previously healthy children die after becoming infected with influenza therefore, the benefits of getting the influenza vaccine outweigh the risks.
The History Of The Flu Virus
The flu is a fascinating subject. Most Australians are exposed in one way or another. Whether you yourself have had the flu or youve seen a family member go through it, you are likely aware of its effects and the illness it can cause the vulnerable, such as children and the elderly. With the 2020 flu season almost upon us, weve pulled together some interesting facts about the flu vaccine and the history of the flu in Australia.
The influenza virus was first isolated in 1933, giving rise to a new era in which all of humanity could be protected from one of the worlds most prolific killers. This breakthrough changed thinking about influenza, as previously the consensus was that the flu was caused by a bacterium known as Haemophilus Influenzae.
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A Brief History Of The Flu Vaccine
Every year, three to five million people catch the seasonal flu, according to the World Health Organization , and between 290,000 and 650,000 people die from it worldwide. Still, thanks to the flu vaccine, this is only a fraction of how many people it used to kill. During the last major flu pandemic of 1918-1919, it killed between 50 and 100 million people around the world.
For a long time, scientists had thought that the flu was caused by a bacteria called Haemophilus influenzae, but after the 1918-19 pandemic, they started to suspect it was caused by a virus instead. However, it wouldnt be until the 1930s that they would confirm that. In 1933, three scientists isolated the Influenza A virus in ferrets one of the three types of flu and in 1936, it was discovered that the virus could be grown inside embryonated chicken eggs, a key step towards making a vaccine.
Just two years later, in 1938, Jonas Salk and Thomas Francis developed the first vaccine using fertilized chicken eggs and an inactivated strain of the Influenza A virus.
This new vaccine was first used to help protect soldiers fighting in World War II it wouldnt be approved for civilians until 1946. According to a 1944 study of the new vaccine, it helped reduce illness that was accompanied by a temperature above 99 degrees Fahrenheit.
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The Nasal Spray Option
People who absolutely cant stand needles may be able to seek out a flu vaccine that can be administered via a nasal spray, notes the CDC. Sold under the brand name FluMist, this form is approved for healthy nonpregnant individuals, 2 through 49 years old.
The nasal vaccine is actually a little bit different from all the other vaccines in that other flu vaccines are inactivated they contain dead parts of the virus, whereas the intranasal one is a live attenuated vaccine, which means that it contains live virus that has kind of been weakened, so that the body can mount an immune response to that, says Philbrick.
She explains that the body simply will not mount an immune response to an inactivated vaccine that is administered intranasally.
Conway points out that the nasal vaccine was restricted for use in those under age 2 because they experienced some side effects such as wheezing.
As far as the restriction for those 50 and older, a spokesperson for FluMists manufacturer, AstraZeneca, says that Based on the clinical studies conducted and submitted for FDA review and approval, the effectiveness of FluMist Quadrivalent has not been established in people aged 50 and older.
Philbrick recommends the traditional flu shot as the method of choice, but if you absolutely cant do needles and otherwise would not get the flu vaccine, the nasal spray would be an appropriate alternative.
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What Ingredients Are In The 2021
Again, every flu vaccine is slightly different, depending on the type and manufacturer. However, the FDA released the most lots of one particular vaccine, the Afluria Quadrivalent vaccine, suggesting this will be the most commonly-used flu vaccine this year. Heres a breakdown of those ingredients:
Strains of the virus
Hemagglutinin are the actual strains of the virus that this vaccine is targeting. Strains are chosen based on what is circulating in terms of flu viruses, Dr. Adalja says. Because the northern and southern hemispheres have opposite flu seasons, one may be used to influence the vaccine components of another.
Sodium chloride, monobasic sodium phosphate, dibasic sodium phosphate, monobasic potassium phosphate, potassium chloride, and calcium chloride are all buffers, says Jamie Alan, Ph.D., an associate professor of pharmacology and toxicology at Michigan State University. They keep the vaccine stable in storage, she explains.
Immune system activator
Sodium taurodeoxycholate is used for splittingthis is a way to activate the immune system without giving adjuvant, Alan says.
Ingredients that appear in residual amounts
- Ovalbumin is used to grown enough of the components of the vaccine
- Sucrose is another stabilizer
The History Of The Flu In Australia
In 1919, the Spanish flu arrived in Victoria. For some time it had been held at bay through the extensive quarantining and blockading procedures put in place at all ports. Over the months following its arrival, it spread throughout New South Wales and the rest of the country. During that time, approximately 10,000 Australians died. The Spanish flu was remarkable for its tendency to cause fatalities in young adults, rather than the elderly or young children.
1957 saw the rise of the next major flu pandemic, known as the Asian flu. This flu was far more widespread than the Spanish flu, but with a much lower fatality rate. This was one of the first instances in the modern era of a major global pandemic originating from bird viruses. In 1968, Australia experienced the Hong Kong flu. This pandemic was relatively mild, with global deaths estimated at one million.
2009 was the year of the H1N1 flu. This strain was new and was believed to have arisen from a combination of human, avian and swine flu. It was first identified in Mexico and quickly spread around the world. For most people who contracted this flu, symptoms were mild. However, for a select few it caused serious complications in the lungs and severe pneumonia. Almost 40,000 cases were recorded in Australia and 191 people died. The median age of death was 53, whereas normal, seasonal flu has a median age of death of around 83.
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The Fifties: Influenza Mismatchand Influenza Surveillance
The first system for the surveillance of circulating influenza virus strains in several countries worldwide was created in 1952 by the World Health Organization in order to monitor the various virus mismatches reported. This important innovative tool enabled the composition of seasonal influenza vaccines to be determined on the basis of the epidemiology of influenza in the previous season . In 1946, as a result of viral mutation, a new variant of influenza A , A/FM/1/47, appeared in Australia. This gave rise to a new influenza subtype, the H2N2 strain, which caused the pandemic known as Asian flu .
The following year, the US Commission on Influenza recommended that a representative of this strain be included in subsequent vaccines.
The emergence of an HA subtype different from those circulating in previous seasons determined the need for pandemic influenza vaccines .
Pigs Pandemics And A Better Vaccine
But even the most effectively formulated seasonal flu shot is, by design, only intended to protect people from the types of flu that commonly circulate in humans.
Among researchers, another main area of concern is the possibility of a flu pandemic, which occurs when a flu virus that typically infects animals, like pigs or birds, changes in such a way that it can spread rapidly and perhaps lethally from person to person.
That’s where experts like veterinarian and professor Andrew Bowman, who leads Ohio State University’s animal influenza research program, come in.
Bowman and his team spend each summer traveling to more than 100 county fairs, where they swab the snouts of exhibition pigs in search of flu strains with pandemic potential. Much like the CDC researchers who analyze human flu specimens, their goal is to use genetic testing to get an early look at potentially troublesome changes in the viruses they capture.
“As we characterize these strains, we can identify viruses that might be able to spread human-to-human so that we can have effective countermeasures in place before … an outbreak, Bowman says. These countermeasures include collaborating with the CDC to have the building blocks of a pandemic flu vaccine at the ready, should the need arise.
But it doesn’t take a pandemic for the flu to be a serious, even fatal, health threat especially for older adults.
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