December 20, 2014
Many of the projected 135-139 million doses of influenza vaccines being produced for this flu season for use in the U.S. are now available to consumers from six manufacturers licensed by the Food and Drug Administration (FDA).
A variety of flu vaccines, including some that were not available during past influenza seasons, are available this year. In addition to the availability of vaccines that protect against three strains of influenza virus (trivalent), vaccines that protect against four strains of the virus (quadrivalent) will also be available this year.
In addition, a vaccine that is produced by growing the virus in cells rather than in eggs will be available for use in people 18 years of age and older.
Unlike eggs, cells can be frozen for later use to grow large volumes of cells for the production of vaccine. This could provide a faster start-up time of the manufacturing process for any unexpected need.
“New technologies are providing additional and diverse influenza vaccines, which helps to ensure an adequate supply in the Unites States,” said Karen Midthun, M.D., director of FDA’s Center for Biologics Evaluation and Research.
“Influenza seasons are unpredictable and can be severe, even deadly,” she added. “Last year’s influenza season brought an increase in reported hospitalizations and deaths compared to recent years, and vaccination is the best defense to prevent influenza.”
All of the vaccines have been determined by FDA to be safe and effective. Getting vaccinated early, before flu season is in full swing, is key to prevention.
Manufacturing flu vaccines is an exacting and complex process. New vaccines must be produced each year because the viruses change from year to year and because the protection received the previous year diminishes over time.
Each February, before one flu season ends, the FDA, World Health Organization, the Centers for Disease Control and Prevention (CDC) and other public health experts collaborate on collecting and reviewing data to identify the virus strains likely to cause the most illnesses in the next flu season. Based on that information and the recommendations of an FDA advisory committee, FDA selects the strains for manufacturers to include in their vaccines for use in the United States.
Both egg-based flu vaccines and vaccines made with newer technologies work the same way; they trigger the immune system of the person receiving the vaccine to produce antibodies capable of attacking the virus.
Vaccines are available in a variety of delivery methods, as a needle into muscle, as a needle injected into skin (approved for ages 18 through 64), and as a nasal spray (approved for people ages 2 through 49). In addition, one vaccine made in a high dose formulation is approved for people 65 years of age and older.
Under traditional egg-based production methods, once the influenza viruses have been selected, they are adapted for use in manufacturing and provided to companies licensed by FDA. The manufacturers inject each virus strain into eggs, which are incubated for several days to allow the virus to multiply.
The virus-loaded fluid from the eggs is then harvested and purified.
Manufacturers grow each strain separately then test it, including for potency. Then the strains are mixed and tested again. Once divided into standard dosages, the vaccines are put into containers such as vials, syringes or sprayers.
Test results are submitted to FDA, along with samples from each batch, or lot. FDA reviews the test results and the samples before releasing the vaccine for distribution in the United States. Each lot, or batch, undergoes testing before release by FDA.
FDA also inspects the manufacturing facilities on a regular basis and continues to monitor the safety of the vaccines once they are in use by the public.
The level of effectiveness can depend on the health and immune system of individuals and how well a particular season’s vaccine strains match circulating flu strains.
There is a possibility of a less than optimal match between the virus strains predicted to circulate and the virus strains that end up causing the most illness. However, even if the vaccine and the circulating strains are not an exact match, the vaccine may reduce the severity of the illness and help prevent influenza-related complications.
CDC recommends that everyone six months of age and older get vaccinated soon after vaccine becomes available. Those people for whom vaccination is particularly important include young children, the elderly, pregnant women, and those who suffer from a variety of chronic illnesses, including asthma, diabetes and heart disease.
Although the winter months are usually the peak month for flu activity, influenza disease in people typically begins appearing in October.
FDA’s website has specific information about each flu vaccine, including the FDA-approved age range of use. The website also provides the names of the influenza viruses included in this season’s vaccines and an up-to-date list of the number of vaccine lots that have been released for each manufacturer.
January 10, 2014
Meant to get vaccinated in the fall to ward off the flu, but somehow didn’t get around to it? Think it’s too late to get vaccinated now?
Not so. According to the Food and Drug Administration (FDA), vaccinations can be protective as long as flu viruses are circulating. And while seasonal flu outbreaks can happen as early as October, flu activity usually peaks in January or February, and can last well into May.
FDA plays a key role in ensuring that safe and effective influenza vaccines are available every flu season. In fact, the task of producing a new vaccine for the next flu season starts well before the current flu season ends. For FDA, it’s a year-round initiative.
Why a new vaccine?
According to Marion Gruber, Ph.D., director of FDA’s Office of Vaccine Research and Review, there are several reasons that new vaccines must be manufactured each year.
“Influenza viruses can change from year to year, due to different subtypes and strains that circulate each year,” says Gruber. A vaccine is needed that includes virus strains that most closely match those in circulation, and the protection provided by the previous year’s vaccine will diminish over time.
Identifying Likely Virus Strains
Each February, before that year’s flu season ends, FDA, the World Health Organization, the Centers for Disease Control and Prevention (CDC) and other public health experts collaborate on collecting and reviewing data from around the world to identify the flu viruses likely to cause the most illnesses in the next flu season. Based on that information and the recommendations of an FDA advisory committee, the agency selects the virus strains for FDA-licensed manufacturers to include in their vaccines for use in the United States.
“The closer the match between the circulating strains causing disease and the virus strains in the vaccine, the better the protection against influenza,” Gruber says.
In addition, FDA inspects the manufacturing facilities on a regular basis, and prepares and provides reagents (necessary test components to standardize vaccines) that vaccine manufacturers need to make their vaccine and to verify its identity and strength. FDA also evaluates each manufacturer’s vaccine each year for approval purposes, conducts lot release (that is, performs certain tests and reviews the results of the manufacturers’ tests on each lot of vaccine prior to distribution), and continues to monitor the safety of the vaccines once they are approved for use and in distribution.
FDA and CDC scientists routinely evaluate reports to the Vaccine Adverse Event Reporting System (VAERS) of health problems that may be associated with a vaccine.
FDA conducts yearly surveillance for Guillain-Barre syndrome, a rare neurological condition associated with the 1976 flu vaccine, in collaboration with the Centers for Medicare and Medicaid Services. And the agency is now testing influenza surveillance in the new Mini-Sentinel Post Licensure Rapid Immunization Safety Monitoring (PRISM) system. If testing proves successful, FDA will be able to monitor rates of health problems after influenza vaccination among members of multiple health plans that serve the general U.S. population.
CDC also monitors the safety of annual influenza and other vaccines through the Vaccine Safety Datalink (VSD) by almost real-time observation of the health of people who are vaccinated, in collaboration with nine integrated health care organizations.
Who’s Most Affected So Far?
CDC tracks influenza activity year round in the U.S. and typically children and seniors are most at risk for influenza, but occasionally a flu virus will circulate that disproportionately affects young and middle-aged adults. So far, data reported by CDC suggest that 2013-2014 could be such a flu season.
CDC received an unusually high number of reports of severe respiratory illness among young and middle-aged adults in the last two months of 2013. Many of the cases were associated with the H1N1 strain of influenza that affected children and young adults compared to older adults during the 2009 influenza pandemic. The 2009 H1N1 virus has circulated each year since the pandemic. It is not known if those most severely affected received a vaccine, but this particular strain is included in this year’s vaccine and will help provide protection.
“Influenza seasons and severity are often unpredictable. Annual influenza vaccination is the best way to prevent influenza among people 6 months of age and older,” says Gruber. “However, taking such practical measures as washing hands, covering coughs and sneezes and staying home when sick can also help to decrease the spread and minimize the effects of flu.”
In addition, while antiviral drugs are not a substitute for vaccine, they can help to treat influenza. Tamiflu (oseltamivir phosphate) and Relenza (zanamivir) are the two FDA-approved influenza antiviral drugs recommended by CDC for use against recently circulating influenza viruses.
September 7, 2013
There is still time to protect your children and yourself from the flu in what remains of a severe influenza season.
“Everyone seems to know that the elderly are particularly vulnerable, but so too are children,” says William Rodriguez, M.D., Ph.D., a pediatrician at the Food and Drug Administration (FDA). “Severe complications are most common in children under age 2, and all children ages 6 months and older should be immunized.”
Rodriguez notes that in each of the last 10 flu seasons, between 43 and 153 children died from influenza in the U.S. An average 20,000 children a year under age 5 are hospitalized. So far this year, 16 deaths of children under age 18 have been reported to the Centers for Disease Control and Prevention (CDC).
Currently, 43 states are reporting widespread flu outbreaks, with the District of Columbia and remaining states—Washington, Oregon, California, Arizona, Montana, South Dakota and Missouri—reporting localized outbreaks.
People are generally immunized in the fall, but they can still get protection from the flu for what remains of the flu season—even though immunization takes several weeks to take effect. The season usually peaks in January or February, with some cases continuing into the spring and even beyond.
“This is particularly late in the flu season for very young children, because to optimize immune response, children between the ages of 6 and 35 months need two shots, four weeks apart, during their first season of vaccination,” said Rodriguez. “However, even one shot provides some protection, so even now there is time to get some benefit.”
November 5, 2011
When flu season arrives this fall, a liquid form of Tamiflu—the most widely used anti-viral flu medication—will be available in a new, lower concentration to reduce the possibility of medication errors.
The change applies to the oral suspension form of Tamiflu and not the capsule. Oral suspension is a powder form of the prescription medication that a pharmacist mixes with water to make a liquid treatment easier to take by children or adults who are unable to swallow a Tamiflu capsule.
Tamiflu is FDA-approved to treat adults and children older than 1 year who have had influenza symptoms for two days or less. Tamiflu stops the virus from spreading in the body and can help shorten the duration of such symptoms as a stuffy or runny nose, sore throat, cough and muscle aches.
Because there are no quality issues with the 12 mg/mL concentration Tamiflu, it will remain on the market until supplies run out and can be used until its expiration date.
With both dose concentrations being available during the flu season this fall, Kendall Marcus, safety deputy in FDA’s Division of Antiviral Products, cautions that pharmacists and physicians will have to be particularly careful in prescribing and dispensing the medication.
After the next flu season, only the 6 mg/mL concentration will be available.
Marcus says consumers need to know the following:
- You could receive either the 6 mg/mL or the 12 mg/mL version at your local pharmacy during the next flu season. If you have any questions about how to use the product safely, speak to your pharmacist or other health care provider.
- If you have taken oral suspension Tamiflu in the past, the container and label will look different.
- The new oral dosing device is different and the volume (mL) of your dose may differ from past prescriptions.
- If you have any problems with the medication, report them to your health care provider and to FDA’s MedWatch program.
Marcus notes that pediatric strength Tamiflu capsules (30 mg and 45 mg) have not changed and are still available for children who can swallow capsules. Another option for parents is to open the capsule and mix its contents with a flavored food, like chocolate syrup.