According to a Press Release by the Centers for Disease Control and Prevention (CDC) on Thursday, early data is suggesting a potentially severe flu season.
Information released Wednesday by Dr. Tom Freiden in a teleconference call, said that this years flu vaccine is not as effective because the current strain of the virus has mutated.
Dr. Tom Frieden said researchers are worried that with this particular strain of the virus, “we could have a season that is more severe than most with more hospitalizations and more deaths.”
The advisory said 52% of the 85 influenza virus samples collected and analyzed from October 1 through November 22 were different than the virus strains included in this year’s vaccine, indicating a mutation, or drift, of the strain.
Here is a look at the Transcript for CDC Telebriefing: Update on Flu Season 2014-15
Click here for the full transcript (about 8 pages).
During the teleconference call Thursday, director of the CDC, Dr. Tom Frieden, stated the flu season is just beginning but that they were seeing some things that are concerning and has led them to issue a health advisory to clinics across the country regarding the flu.
One thing to understand about flu always is that it is unpredictable. Every season is different with different flu viruses spreading and causing illness. So far, this season influenza A, which is called H3N2 viruses have been detected most frequently and in almost all states. We know that in seasons when H3 viruses predominant, we tend to have seasons that are the worst flu years, with more hospitalizations from flu and more deaths from the flu. Unfortunately, about half of the H3N2 viruses that we’ve analyzed this season are different from the H3N2 virus that’s included in this year’s flu vaccine. They are different enough that we’re concerned that protection from vaccinations against these drifted H3N2 viruses may be lower than we usually see. Most of the other viruses identified are the same as the viruses covered by the vaccine. We continue to recommend flu vaccine as the single best way to protect yourself against the flu. Vaccine will protect against the strands that are covered in the vaccine and may have some effectiveness against the drifted strain.
He highlighted that a second tool to fight the flu were antiviral medications.
Vaccinations prevent flu, but antivirals are an important second line of defense to treat the flu. This year, treatment with antiviral drugs is especially important, particularly for people who are at high risk of serious flu complications or for people who are very sick with flu. It’s especially important to get antiviral medicines quickly if you have flu. They work best when you start them within two days of the beginning of flu symptoms, and we strongly recommend that if doctors suspect the flu in someone who may be severely ill from the flu, they don’t wait for the results of a flu test before starting antivirals.
He then explained the flu shot may be less effective this year.
Influenza activity has increased slightly in parts of the U.S. and surveillance data indicates that influenza A, H3N2 viruses have predominated so far with lower levels of detection of influenza B viruses and very few of the H1N1 viruses we’ve seen a few years ago.
(Editor’s note – due to length of the explanation, broken down into bullets for easier reading)
- During the week ending November 22nd, 91 percent of the approximately 1,200 flu positive tests reported to the CDC were influenza A, and 9 percent were influenza B viruses. As I noted before, of the influenza A viruses, nearly all were H3N2, and of those, about half were antigenetically different from the H3N2 component of the 2014 flu vaccine.
- These changes can signal that the immune response provided by vaccinations won’t protect as well for these viruses, and there’s a lot of numbers there. Let me go over them again.
- What we are seeing this year is largely an H3 year, about 90 percent of the viruses we’ve typed so far are H3. Of the 90 percent, about half are well matched with the vaccine strain, and about half are poorly matched with the vaccine strain, so for the B viruses, about 10 percent, those are well matched.
- For half of the 90 percent, they are well matched, but for the other half of the 90 percent, they are not well matched, and we may well see less effectiveness, although there also could be some effectiveness against influenza even for the drifted viruses from the vaccine.
- The drifted viruses were first detected in March of 2014 after — when it was already too late to include them in this season’s vaccine.
- At that time, the current vaccine component, the one that’s covered, the H3 vaccine that’s in the strain, that is in the vaccine, was still by far the most common of the H3N2 viruses.
- These viruses, both the H3 that’s well matched and the H3 that’s poorly matched are likely to continue to circulate in the U.S. this season, and there is no way to predict with certainty what is going to happen.
- We have four different strains of flu circulating: The B strain, the h1 strain, the well matched H3 strain, and the poorly matched H3 strain, and only time will tell which of them, if any, will predominate for the following weeks and months of this year’s flu season.
- Flu always has a potential to be serious, but H3N2 viruses tend to be associated with more severe seasons. The rate of hospitalization and death can be twice as high as or more than in flu season when H3 doesn’t predominate.
- People with certain health conditions like asthma, diabetes, heart disease, lung disease, and pregnancy are also at high risk. We’re also noting our hospitalizations for the year, and we know, sadly, that so far there have been five pediatric deaths associated with influenza.
- We’ve also heard of outbreaks in schools and in nursing homes. During some seasons when the viruses are antigenically drifted, vaccine effectiveness can be lower, but that’s not always the case.
- If we have a severe season with H3N2 virus predominating, getting a vaccine even if it does not provide as good as protection as we hope would be more important than ever and remains the single most important way to protect yourself against the flu.
- In addition, a vaccination will offer the usual protection of circulating viruses that have not undergone antigenetic draft.
- We continue to recommend vaccination, because though far from perfect, it still offers us the best chance for prevention. We can’t predict what will happen over the entire season.
- The influenza vaccine is designed to protect from three or four, depending what vaccine you get, different influenza viruses. Any of these could circulate at any time in the season, and if we have a severe season, getting a vaccine that provides partial protection may be more important than ever, so, first, we urge people who have not been vaccinated to get a vaccine now.
- Companies have already distributed close to 150 billion doses this year. As I mentioned earlier, antiviral treatment is particularly important this year. Many people believe that since flu is a virus, there’s no treatment for it.
- In fact, there are antiviral drugs that work to reduce the severity of influenza. There are two FDA approved drugs recommended for use in the U.S. during this season, Oseltamivir and Zanamivir. Treatment with antiviral drugs works best when they are begun 48 hours of getting sick, but they can still be helpful in some patients when given later in the course of the illness. Treatments with antiviral drugs for influenza can make your illness milder and shorter. It can reduce the likelihood you’ll end up in a hospital or in intensive care, and we believe treatment with antiviral drugs can reduce the risk of dying from influenza.
- Prescription antiviral drugs, however, are greatly under prescribed, particularly for people who are at very high risk of getting the flu. Probably fewer than one in six people who are severely ill with the flu get antiviral drugs.
- Very important that we do better for people who are severely ill or who could become severely ill with influenza.
- That’s the single most important message of this telebriefing. We need to get the message out that treating early with the drugs makes the difference between a milder illness or a very severe illness. Time is important when it comes to treatment for influenza.
- Antiviral drugs are even more important when circulating viruses are different from the vaccine virus. This can mean the vaccine is not as effective in this year as it has been in the past, and that cannot only have more people coming down with severe illness, but also crowding emergency departments and hospitals.
- I also want to remind people of another defense against respiratory viruses like the flu are simple things like staying home if you’re sick so that you don’t make other people sick.
- I’ll conclude by reiterating we cannot predict what’s going to happen in the rest of the flu season. It is possible we could have a season that’s more severe than most with more hospitalizations and tragically more deaths.
- I want to urge anyone who has not got vaccinated to get vaccinated. It’s still our best tool to prevent influenza. I’ve been vaccinated. My family’s been vaccinated. If you have not been vaccinated, get vaccinated. Second, to encourage you if you are sick, talk to your doctor promptly about getting antiviral treatment because that can help you get healthy quicker. Third, take everyday actions like covering your cough and staying home if you’re sick. With that, I’ll stop, and we’ll open for questions.
- Click here for the full transcript.
Dec. 4 Press Release:
Early Data Suggests Potentially Severe Flu Season
Early data suggests that the current 2014-2015 flu season could be severe. The Centers for Disease Control and Prevention (CDC) urges immediate vaccination for anyone still unvaccinated this season and recommends prompt treatment with antiviral drugs for people at high risk of complications who develop flu.
So far this year, seasonal influenza A H3N2 viruses have been most common. There often are more severe flu illnesses, hospitalizations, and deaths during seasons when these viruses predominate. For example, H3N2 viruses were predominant during the 2012-2013, 2007-2008, and 2003-2004 seasons, the three seasons with the highest mortality levels in the past decade. All were characterized as “moderately severe.”
Increasing the risk of a severe flu season is the finding that roughly half of the H3N2 viruses analyzed are drift variants: viruses with antigenic or genetic changes that make them different from that season’s vaccine virus. This means the vaccine’s ability to protect against those viruses may be reduced, although vaccinated people may have a milder illness if they do become infected. During the 2007-2008 flu season, the predominant H3N2 virus was a drift variant yet the vaccine had an overall efficacy of 37 percent and 42 percent against H3N2 viruses.
“It’s too early to say for sure that this will be a severe flu season, but Americans should be prepared,” said CDC director Tom Frieden, M.D., M.P.H. “We can save lives with a three-pronged effort to fight the flu: vaccination, prompt treatment for people at high risk of complications, and preventive health measures, such as staying home when you’re sick, to reduce flu spread.”
Depending on the formulation, flu vaccines protect against three or four different flu viruses. Even during a season when the vaccine is only partially protective against one flu virus, it can protect against the others.
“While the vaccine’s ability to protect against drifted H3N2 viruses this season may be reduced, we are still strongly recommending vaccination,” said Joseph Bresee, M.D., Chief of the Influenza Epidemiology and Prevention Branch at CDC. “Vaccination has been found to provide some protection against drifted viruses in past seasons. Also, vaccination will offer protection against other flu viruses that may become more common later in the season.”
Influenza viruses are constantly changing. The drifted H3N2 viruses were first detected in late March 2014, after World Health Organization (WHO) recommendations for the 2014-2015 Northern Hemisphere vaccine had been made in mid-February. At that time, a very small number of these viruses had been found among the thousands of specimens that had been collected and tested.
A committee of experts must pick which viruses to include in the vaccine many months in advance in order for vaccine to be produced and delivered in time for the upcoming flu season. There is always the possibility that viruses will drift during that time.
Influenza activity is currently low in the United States as a whole, but is increasing in parts of the country. “We are just at the beginning of the season. It’s not too late to get your vaccine,” Dr. Frieden says.
Influenza antiviral drugs – Tamiflu (oseltamivir) and Relenza (zanamivir) can reduce severe complications such as hospitalization and potentially death for people who are at high risk of serious flu complications or are very sick. Treatment of high risk patients should begin as soon after symptoms develop as possible, without waiting for lab tests to confirm flu infection.
Those at high risk from influenza include children younger than 5 years (especially those younger than 2 years); adults 65 years and older; pregnant women; and people with certain chronic health conditions such as asthma, diabetes, heart or lung disease, and kidney disease.
CDC recommends that people at high risk check with their doctor or other health care professional promptly if they get flu symptoms. Studies show that flu antiviral drugs work best for treatment when they are started in the first 48 hours after symptoms appear. Flu symptoms can include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and fatigue.
Source:
http://www.cdc.gov/media/releases/2014/p1204-flu-season.html
