Image copyright F.D.A Image caption The dosage can be adjusted based on flu antigen levels
The US Food and Drug Administration has approved a new influenza vaccine containing the government’s first swine flu swine-specific ingredient in over 20 years.
The expanded adult vaccine’s combination of live and dead cells will be used to fight swine flu, and another strain known as H5N1.
If the FDA decision is eventually approved by other global regulatory agencies, the single-dose vaccines would be available to over 97% of US adults.
The polyvalent shot will be included in the autumn influenza shot as a supplement.
This expanded elderly adult vaccine contains up to 50% swine flu in a single dose, according to the FDA, so it will be important to adjust the dose to cater for individuals who may have weakened immune systems.
People eligible for the two-dose adult vaccine must be 65 years of age or older.
The human swine flu (H3N2) seasonal vaccine has already been recommended for use in adults and children aged 6 months to 49 years.
The agency also recommended that men, women and children between the ages of 50 and 64 who have already received H3N2, plus others who have received either B or A-style winter flu shots, or people aged 64 and over who have not been vaccinated in the past.
The pandemic version of the H3N2 (H1N1) influenza vaccine was available since 2015.
Anyone 18 and older who has not been vaccinated against the infection should get a new shot by the end of October, and is not being recommended to get the seasonal flu shot until January or February.
The swine flu (H1N1) virus poses a greater threat to infants and people with pre-existing health conditions, including respiratory diseases and cardiac disease.
But this vaccine has proven to be only 25% effective at preventing the infection.
Symptoms of this flu virus mainly include high fever, cough, runny nose, sore throat, headaches, chills and fatigue.
How the experimental vaccine works
Image copyright The Center for Disease Control and Prevention Image caption This one-shot swine flu vaccine is expected to be available for everyone aged 65 and older
The safety of the two-dose seasonal flu shot has been evaluated by an international panel of experts and data has shown the injection doesn’t leave many people with red and inflamed injection sites or side effects like aches and dizziness, according to the US agency.
US consumer groups like Dr. Mona Bhatt said she hopes the FDA will clear the entire annual flu vaccine.
“For every year, most adults should get vaccinated against the flu,” she told the BBC.
“They are a really vulnerable population and studies show that the death rate during epidemics is largely due to complications from the flu. The flu vaccine has proven to be a reasonable option for those who can’t be vaccinated.”
She added: “A third of the people who get flu never come down with it.”
The maximum dose of the swine flu vaccine used in the swine flu vaccine is in the form of a gel
Image copyright The Center for Disease Control and Prevention Image caption The swine flu vaccine is of little use against flu viruses in people under 18
The maximum dose of the swine flu vaccine used in the swine flu vaccine is in the form of a gel and can be prepared in larger batches for older adults.
It contains virus taken from the preserved swine hemagglutinin protein.
Live vaccine – the opposite – is often used for people who cannot tolerate the live vaccine.
In the swine flu shot, a live, killed viral virus is included in the vaccine.
The US government requires that if a new strain is identified and there is an expectation of more than one new virus being spread by a person, the US Centres for Disease Control and Prevention advises that people be vaccinated against all types of flu – not just swine flu – as a precaution.
The swine flu vaccine is of little use against flu viruses in people under 18 years of age.
Because children under 18 are more vulnerable to the influenza virus, they should not be vaccinated.
This maximum dose of the swine flu vaccine is 50% more than the limit recommended by the Centers for Disease Control and Prevention.
However, the likelihood of contracting the flu is decreased by about 50% when a person is vaccinated against all strains of the flu.
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