How Influenza Vaccines Are Made
For the United States there are three different influenza vaccine production technologies approved by the U.S. Food and Drug Administration external icon:
- egg-based flu vaccine,
- cell-based flu vaccine, and
- recombinant flu vaccine.
All commercially available flu vaccines in the United States are made by private sector manufacturers. Different manufacturers use different production technologies, but all flu vaccines meet FDA safety and effectiveness requirements. Different vaccines have different indications. See Different Types of Flu Vaccines for more information.
Why Should People Get Vaccinated Against Flu
Influenza is a potentially serious disease that can lead to hospitalization and sometimes even death. Every flu season is different, and flu can affect people differently, but millions of people get flu every year, hundreds of thousands of people are hospitalized and thousands to tens of thousands of people die from flu-related causes every year. Flu can mean a few days of feeling bad and missing work or it can result in more serious illness. Complications of flu can include bacterial pneumonia, ear infections, sinus infections and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes. An annual seasonal flu vaccine is the best way to help protect against flu. Vaccination has been shown to have many benefits including reducing the risk of flu illnesses, hospitalizations and even the risk of flu-related death in children. While some people who get a flu vaccine may still get sick, flu vaccination has been shown in several studies to reduce severity of illness.
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.
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The Next Stage Will Be Fast Too
Plans for giving regulatory approval and manufacturing the vaccine have also been dramatically speeded up.
The UK already has four million doses of the vaccine ready to deploy. The Oxford team partnered with pharmaceutical giant AstraZeneca, and the manufacture of the vaccine started long before the results came in. At the time it was a gamble, but it has paid off big time.
Regulators, who would normally wait until after the trials were concluded, have also been involved early.
The Medicines and Healthcare products Regulatory Agency in the UK has been conducting “rolling reviews” of the safety, manufacturing standards and effectiveness of the Oxford vaccine. It means a decision on whether the vaccine can be used will come early.
The Oxford vaccine has – like those of Pfizer and Moderna – arrived in record time to a world in desperate need.
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.
Know your flu risk. Check out the Flu Tracker on The Weather Channel App.
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Does A Flu Vaccine Increase Your Risk Of Getting Covid
There is no evidence that getting a flu vaccine increases your risk of getting sick from a coronavirus, like the one that causes COVID-19.
You may have heard about a study published in January 2020 that reported an association between flu vaccination and risk of four commonly circulating seasonal coronaviruses, but not the one that causes COVID-19. This report was later found to be incorrect.
The results from that initial study led researchers in Canada to look at their data to see if they could find similar results in their population. The results from Canadas study showed that flu vaccination did not increase risk for these seasonal coronaviruses. The Canadian findings highlighted the protective benefits of flu vaccination.
The Canadian researchers also identified a flaw in the methods of the first study, noting that it violated the part of study design that compares vaccination rates among patients with and without flu . This flaw led to the incorrect association between flu vaccination and seasonal coronavirus risk. When these researchers reexamined data from the first study using correct methods, they found that flu vaccination did not increase risk for infection with other respiratory viruses, including seasonal coronaviruses.
Why Do I Need A Flu Vaccine Every Year
A flu vaccine is needed every season for two reasons. First, a persons immune protection from vaccination declines over time, so an annual vaccine is needed for optimal protection. Second, because flu viruses are constantly changing, flu vaccines may be updated from one season to the next to protect against the viruses that research suggests may be most common during the upcoming flu season. For the best protection, everyone 6 months and older should get vaccinated annually.
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Why Do I Need To Get Vaccinated Every Year
Youve probably noticed by now that we encourage our patients to get vaccinated each year. Why does this particular vaccine need to be administered again, even if you got a flu shot last year? Its because new strains of the virus are constantly appearing and evolving, so the vaccine must change along with them.
Located around the world are influenza surveillance centers that annually monitor the most common strains, collecting data and identifying new and evolving strains. Once the information has been collected, the World Health Organization selects the three strains most likely to circulate during the following flu season. This decision is typically made in February, allowing the development of a new vaccine to begin around midsummer.
Because the three strains change each year, the vaccines are formulated separately before theyre combined into the final product, the trivalent vaccine. While its usually fairly accurate, there have been instances, such as the infamous H1N1 outbreak in 2009, that required the addition of a second, separate vaccination.
In addition to the constantly evolving strains of the flu virus, your bodys immune response changes over time. Taken together, those two factors essentially render the previous years vaccinations useless against new strains. This is why its so important to get yourself vaccinated each and every year, even if you got the vaccine last year!
Northern Hemisphere Influenza Season
The composition of trivalent virus vaccines for use in the 2017â2018 Northern Hemisphere influenza season recommended by the Advisory Committee on Immunization Practices on August 25, 2017, was:
- an A/Michigan/45/2015 pdm09âlike virus
- an A/Hong Kong/4801/2014 -like virus
- a B/Brisbane/60/2008âlike virus
In addition to these components, quadrivalent vaccines will also include a B/Phuket/3073/2013âlike virus .
In California, some emergency systems were strained by a spike in H3N2 flu cases. In addition, some areas experienced local shortages of oseltamivir. The severity of the flu season seemed somewhat comparable to the 2009â10 swine flu outbreak. A February 2018 CDC interim report estimated the vaccine effectiveness to be 25% against H3N2, 67% against H1N1, and 42% against influenza B.
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Experimental Flu Vaccine Could Last For Years Early Results Show
Each year when influenza season arrives, experts worry that the flu vaccine wont match the currently circulating strains of the virus.
The results of an early-stage trial suggest that may become a thing of the past in the not-too-distant future. Researchers found in the Phase 1 trial that a universal flu vaccine, one designed to protect against all strains of the flu, sparked a strong immune response while producing no more side effects than the current seasonal flu vaccines, according to a report published Monday in Nature Medicine.
This was the first time that a Phase 1 study in humans looked at a rationally designed vaccine that has the potential to protect against all kinds of seasonal flu, as well as a potential flu pandemic, said study co-author Florian Krammer, a vaccine specialist and a professor of microbiology at the Icahn School of Medicine at Mt. Sinai in New York. It shows that its possible to think about how to design a vaccine to get the immune system to do what you want and how to rationally design vaccines to get broad protection.
What Protection Does A Flu Vaccine Provide If I Do Get Sick With Flu
Some people who get vaccinated may still get sick. However, flu vaccination has been shown in some studies to reduce severity of illness in people who get vaccinated but still get sick. A 2017 study showed that flu vaccination reduced deaths, intensive care unit admissions, ICU length of stay, and overall duration of hospitalization among hospitalized adults with flu. Another study in 2018 showed that a vaccinated adult who was hospitalized with flu was 59 percent less likely to be admitted to the ICU than someone who had not been vaccinated. Among adults in the ICU with flu, vaccinated patients on average spent 4 fewer days in the hospital than those who were not vaccinated.
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Who Will Want The Swine Flu Vaccine
A decision will be made whether to deploy pandemic swine flu vaccine for some or all U.S. residents. If that happens, the CDC will begin an intensive campaign to persuade people at high risk of flu complications to get vaccinated. The program will have to address issues of vaccine safety in a straightforward manner. “Public trust is crucial we risk it at our peril. If we risk public trust with bad vaccination decisions, it will take us years to recover,” Pavia warns.
“You are going to have less data than you want to make a decision on the go or no-go, but you are going to have to make it on the best available data at the time,” says Gellin. “The middle of September is where all this stuff theoretically converges. That is the point where at least we think we will have preliminary data to see how the vaccine is performing and say where are we with this epidemic and what is the situation.”
A Needle In A Haystack
The challenge starts with the virus itself.
An expert shape-shifter, the flu is constantly changing mutating as it replicates itself in ways that allow its strains to get past our body’s immune defenses even if we’ve had the flu before, or if we roll up our sleeves for the shot each fall.
The result? It’s a bit of a war between us and the virus, says David Wentworth, director of the WHO Collaborating Centre for Influenza in the U.S., which is run out of the Centers for Disease Control and Prevention in Atlanta.
This battle plays out not only within the bodies of people who come down with the flu’s signature fever, chills and muscle aches, but also in laboratories around the world, where researchers must work quickly to analyze how the flu virus is changing in order to predict what it might do next.
The worldwide system of surveillance starts when specimens from sick patients are sent to the lab for testing. Of those, about 7,000 end up at the laboratory run by microbiologist John Barnes, who leads the CDC’s influenza genomics team.
“We’re always busy, and we’re always getting new viruses to work on, Barnes says. He and his team perform year-round genetic sequencing to determine how flu viruses are behaving, both in terms of which strains are infecting people and other characteristics, like whether a specimen shows signs of resistance to the antiviral drugs that can treat the flu.
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Phase I Clinical Trials To Assess Safety Dosing And Immune Responses
Phase I clinical trials are the first step in assessing vaccines in people. Typically involving one to several dozen healthy volunteers, phase I trials assess short-term safety and immune responses, often with different vaccine dosages. Only if a vaccine candidate is shown to be safe in phase I trials will it move to larger phase II trials.
Phase 1 trials can be completed in two to three months, allowing for two doses of a vaccine three to four weeks apart
Measles Mumps And Rubella
Measles, Mumps, and Rubella are viral infections that have each caused widespread, deadly disease outbreaks. Throughout the 1960s, individual vaccines were developed for each of them, but a decade later, they were combined into one.
Measles was the first of the three to receive its own vaccine in 1963, followed by mumps in 1967, and rubella in 1969. Two years later, in 1971, Maurice Hilleman of the Merck Institute of Therapeutic Research developed a combined vaccination that would provide immunity for all three viruses.
Hilleman was credited with creating the first measles and mumps vaccine, and began researching ways to incorporate a system of immunity for each virus. Using his previous research and a rubella vaccine developed by Stanley Plotkin in 1969, he created the first successful MMR vaccine in just two years.
According to the CDC, “One dose of MMR vaccine is 93% effective against measles, 78% effective against mumps, and 97% effective against rubella.”
“Two doses of MMR vaccine are 97% effective against measles and 88% effective against mumps.”
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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.
First Us Cycling Club Formed
Karl Habel at the U.S. Health Service used the egg technique to produce the very first experimental mumps vaccine in 1946. Habels vaccine was inactivated, meaning it contained no live mumps virus, just dead virus particles. The inactive mumps vaccine was tested on 2,825 West Indian workers at a Florida sugarcane plantation where mumps ran rampant, and it showed a 58 percent effectiveness against the virus.
The world had its first mumps vaccine, but by that time WWII was over and the urgency to find a mumps cure had passed.
In the 1940s, the CDC hadnt identified mumps among children as a top health priority, says Conis. After the war was over, illnesses like pneumonia and the flu were a much bigger concern. Parents didnt like when their kids got mumps, but was considered an expected part of childhood.
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What Are The Benefits Of Flu Vaccination
There are many reasons to get an influenza vaccine each year. Below is a summary of the benefits of flu vaccination and selected scientific studies that support these benefits.
Flu vaccination can keep you from getting sick with flu.
Flu vaccination can reduce the risk of flu-associated hospitalization for children, working-age adults, and older adults.
Flu vaccination is an important preventive tool for people with chronic health conditions.
Flu vaccination has been associated with lower rates of some cardiac events among people with heart disease, especially among those who had had a cardiac event in the past year.
Flu vaccination can reduce worsening and hospitalization for flu-related chronic lung disease, such as in persons with chronic obstructive pulmonary disease.
Flu vaccination also has been shown in separate studies to be associated with reduced hospitalizations among people with diabetes and chronic lung disease.
Flu vaccination helps protect women during and after pregnancy.
Flu vaccines can be lifesaving in children.
Flu vaccination has been shown in several studies to reduce the severity of illness in people who get vaccinated but still get sick.
The study finding links to support these findings can be found here: