Tag: flu vaccine strains

Is H1N1 Flu Back This Year?

You remember H1N1 flu, right?

Is it back this year?

Is H1N1 Flu Back This Year?

While H1N1 seems to be the most frequently identified influenza virus type this year, in reality, since causing the “swine flu” pandemic in 2009, this strain of flu virus never really went away.

It instead became a seasonal flu virus strains.

So it is back again this year, but just like it was back during the 2013-14 and 2015-16 flu seasons.

Is that good news or bad news?

In general, it’s good news, as “flu vaccines provide better protection against influenza B or influenza A (H1N1) viruses than against influenza A (H3N2) viruses.”

“The 2009 H1N1 influenza virus (referred to as “swine flu” early on) was first detected in people in the United States in April 2009. This virus was originally referred to as “swine flu” because laboratory testing showed that its gene segments were similar to influenza viruses that were most recently identified in and known to circulate among pigs. CDC believes that this virus resulted from reassortment, a process through which two or more influenza viruses can swap genetic information by infecting a single human or animal host. When reassortment does occur, the virus that emerges will have some gene segments from each of the infecting parent viruses and may have different characteristics than either of the parental viruses, just as children may exhibit unique characteristics that are like both of their parents. In this case, the reassortment appears most likely to have occurred between influenza viruses circulating in North American pig herds and among Eurasian pig herds. Reassortment of influenza viruses can result in abrupt, major changes in influenza viruses, also known as “antigenic shift.” When shift happens, most people have little or no protection against the new influenza virus that results.”

Origin of 2009 H1N1 Flu (Swine Flu): Questions and Answers

The only reason we were so concerned about this strain of H1N1 in 2009 was because it was new.

Still, even in a good year, it is important to remember that a lot of people die with the flu, including a lot of kids. And most of them are unvaccinated.

So while it might be interesting to talk about which flu virus strain is going around, just remember that your best protection against that strain is a yearly flu vaccine.

More on H1N1 Flu

Is This Year’s Flu Vaccine Working?

Breaking News – Interim Estimates of 2018–19 Seasonal Influenza Vaccine Effectiveness have now been released (see below)

Flu season is just getting started, but I’m sure that you have already heard folks rating how well this year’s flu shots are working.

Are flu vaccines working well?
Are flu vaccines working well?

Of course, if you had a flu shot and have already gotten the flu, then you’re gonna think the flu shot isn’t working very well at all.

And if you are vaccinated and protected and have avoided the flu, then it is working so far, right?

Is This Year’s Flu Vaccine Working?

While we won’t know how well this year’s flu vaccine is working until the CDC releases the preliminary estimates on flu vaccine effectiveness, there are some good signs already.

  1. The majority of the influenza viruses collected from the United States so far have been “characterized antigenically and genetically as being similar to the cell-grown reference viruses representing the 2018–2019 Northern Hemisphere influenza vaccine viruses.”
  2. The most frequently identified influenza virus type reported by public health laboratories was influenza A(H1N1)pdm09 virus.

Remember, to be effective, you want the flu vaccine to match the strains of flu virus that are circulating in the community. A mismatch in flu virus strain or antigenic drifting leads to lower flu vaccine effectiveness (VE).

Remember the 2004-05 flu season? That was the year that because of a drifted A(H3N2) virus, “only 5% of viruses from study participants were well matched to vaccine strains.” And the flu vaccine wasn’t very effective at all.

Still, even when the flu vaccine matches circulating strains, in general, as we have certainly seen, “flu vaccines provide better protection against influenza B or influenza A (H1N1) viruses than against influenza A (H3N2) viruses.”

YearFlu Virus StrainVE
2004-05A(H3N2)10
2005-06A(H3N2)21
2006-07A(H1N1)52
2007-08A(H3N2)37
2008-09A(H1N1)41
2009-10A(H1N1)pdm0956
2010-11A(H3N2)60
2011-12A(H3N2)47
2012-13A(H3N2)49
2013-14A(H1N1)pdm0952
2014-15A(H3N2)19
2015-16A(H1N1)pdm0948
2016-17A(H3N2)40
2017-18A(H3N2)40
2018-19A(H1N1)pdm0947

So if you had to guess, you could probably say that this year’s flu vaccine is going to be at least 50% effective.

So just as good as flipping a coin? Not exactly.

There are a lot of benefits to getting a flu shot besides avoiding the flu, like avoiding severe flu, hospitalization, and death.

And since flu vaccines are safe and flu can be a life-threatening disease, even in those without any medical problems, wouldn’t you take any chance you could to reduce your child’s chances of getting sick?

When will we know how well this year’s flu vaccine is really working?

The CDC typically releases the first preliminary flu vaccine effectiveness report of the season in February.

Not that you should wait! Flu season is well underway and this is a great time to get a flu vaccine and get protected for the rest of flu season.

Interim Estimates of 2018–19 Seasonal Influenza Vaccine Effectiveness

On schedule, the CDC has released this year’s Interim Estimates of 2018–19 Seasonal Influenza Vaccine Effectiveness.

During this period, overall adjusted vaccine effectiveness against all influenza virus infection associated with medically attended ARI was 47% (95% confidence interval [CI] = 34%–57%). For children aged 6 months–17 years, overall vaccine effectiveness was 61% (44%–73%).

Interim Estimates of 2018–19 Seasonal Influenza Vaccine Effectiveness — United States, February 2019

That’s certainly better than we have seen in recent years.

More on the Effectiveness of This Year’s Flu Vaccine

Updated February 15, 2019

I’m Not Anti-Vaccine, I Just Don’t Believe in Flu Shots

Do you know any of these folks?

“I’m not anti-vaccine, I just don’t believe in flu shots.”

They likely get all other available vaccines for themselves and their kids, but for some reason, they skip the flu shot each year.

I’m Not Anti-Vaccine, I Just Don’t Believe in Flu Shots

Are they just anti-flu vaccine? Is that a thing?

Gloria Copeland told her followers that they didn’t need flu vaccinations because Jesus already “redeemed us from the curse of the flu.”
Gloria Copeland told her followers that they didn’t need flu vaccinations because Jesus already “redeemed us from the curse of the flu.”

Why don’t they “believe” in flu shots?

Typical answers you might get, if you ask, include:

  • I never get the flu – since about 5 to 20% of people get the flu each year, it is certainly possible that you never get the flu, especially if you aren’t around many other people that could spread the flu virus to you. But unless you live and work in a bubble, there is a good chance that you will eventually be exposed to someone with the flu, might catch the flu yourself, and will spread it to someone else.
  • I only get sick when I get a flu shot – flu shots are inactivated and can’t actually give you the flu. Even the live virus nasal mist flu vaccine won’t cause you to have the flu. While flu vaccines can cause mild flu side effects, if you get sick after after a flu shot, it could be that you have another respiratory virus, your flu vaccine didn’t have time to work, or that it wasn’t effective.
  • I don’t need a flu shot – you do, if you want to reduce  your chances of getting the flu and having serious complications from a flu infection, which can affect anyone.
  • I got a flu shot last year – you need a flu vaccine each year
  • Flu vaccines don’t work – flu vaccines aren’t perfect, but they can reduce your risk of catching the flu and avoiding serious complications, even if you do get sick.
  • Flu shots are too expensive – most insurance plans cover the costs of flu vaccines, but  if you don’t have insurance, it is sometimes possible to find free flu shots at a local health clinic, or you could get a flu shot for $24 at Walmart with a GoodRx coupon.
  • I don’t have time to get a flu shot – do you have time to get sick with the flu? Many doctors now offer regular flu clinics that make it convenient to just come in and get a flu vaccine or if that isn’t possible, you can likely get a flu vaccine at a nearby pharmacy.
  • Someone on the Internet told me to never get a flu shot because they are poison – if you are avoiding a flu vaccine because you are worried about thimerosal, miscarriages, that they contain a vaginal spermicide, or other misinformation, then you likely aren’t just anti-flu vaccine…
  • Gloria Copeland told me I didn’t need one – Jesus didn’t give us a flu shot and doesn’t want you to die with the flu, or measles.

Stop making excuses, none of which hold water.

Get your flu vaccine, preferably before flu season starts and you start seeing flu activity in your area.

More on Being Anti-Flu Vaccine

Why Do You Need to Get a Flu Vaccine Each Year?

A yearly flu vaccine is the best way to protect yourself and your family against the flu.

But why do you need to get a flu vaccine each and every year?

Why Do You Need to Get a Flu Vaccine Each Year?

Hopefully we will one day have a universal flu vaccine that covers all flu strains and offers longer lasting protection.

Most folks know we don’t have that flu vaccine yet…

“A flu vaccine is needed every season for two reasons. First, the body’s immune response from vaccination declines over time, so an annual vaccine is needed for optimal protection. Second, because flu viruses are constantly changing, the formulation of the flu vaccine is reviewed each year and updated as needed to keep up with changing flu viruses. For the best protection, everyone 6 months and older should get vaccinated annually.”

CDC on Key Facts About Seasonal Flu Vaccine

So because the protection from the flu vaccine wanes or wears off relatively quickly, even if the flu vaccine strains don’t change from one year to the next, you should get a new flu vaccine.

How long does the protection from the flu vaccine last?

“An analysis from the 2011–12 through 2013–14 seasons noted protection ranging from 54% to 67% during days 0 through 180 postvaccination.”

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season

The flu vaccines takes about two weeks to become effective and should then last for at least six months – long enough to get  you through the average flu season.

“A number of observational studies and a post hoc analysis from a randomized controlled trial have reported decreases in vaccine effectiveness (VE) within a single influenza season, with increasing time postvaccination. Waning effects have not been observed consistently across age groups, virus subtypes, and seasons; and observed declines in protection could be at least in part attributable to bias, unmeasured confounding, or the late season emergence of antigenic drift variants that are less well-matched to the vaccine strain. Some studies suggest this occurs to a greater degree with A(H3N2) viruses than with A(H1N1) or B viruses . This effect might also vary with recipient age; in some studies waning was more pronounced among older adults and younger children. Rates of decline in VE have also varied.”

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season

That means it should last past the peak of the average flu season, which is typically between December and March.

And in most young, healthy people, the protection likely lasts even longer.

Make sure you are vaccinated well before flu season starts.
Make sure you are vaccinated well before flu season peaks, which since 1982 has occurred as early as October and as late as March, but is most common in February.

Still, there is some concern that the protection from the flu vaccine can wear off during a flu season, especially if you are very young, very old, or have chronic medical problems, and you get your flu vaccine early and you get exposed late – in April or May.

Of course, that’s not a good reason to delay getting a flu vaccine though, as waiting too long might leave you unprotected if flu peaks early, in October or November.

What to Know About Why You Need the Flu Vaccine Every Year

Since the flu vaccine strains can change and protection doesn’t last from season to season, get a flu vaccine each year. It’s the best way to protect yourself and your family against the flu.

More on Why You Need the Flu Vaccine Every Year

Do They Really Just Guess at Which Strain to Put in the Flu Vaccine?

Every year we hear experts telling us to get vaccinated against the flu.

And more often than not, we hear critics telling us that the flu vaccine isn’t going to work that well because it isn’t a good match.

Is that because they just guess at which flu strains to put into the flu vaccine each year, as some folks say?

Do They Really Just Guess at Which Strain to Put in the Flu Vaccine?

Of course they don’t guess at which vaccine strain to put in the flu vaccine!

“Flu viruses are constantly changing, so the vaccine composition is reviewed each year and updated as needed based on which influenza viruses are making people sick, the extent to which those viruses are spreading, and how well the previous season’s vaccine protects against those viruses.”

CDC on Selecting Viruses for the Seasonal Influenza Vaccine

There are over 100 flu centers in over 100 countries that are involved in testing thousands of flu virus samples each year. Representative samples from these centers then go to the five major World Health Organization (WHO) Collaborating Centers for Reference and Research on Influenza.

The directors of these centers review these samples and other available information and make a recommendation on which vaccine strains to include in the flu vaccine for the next flu season. Each country then considers this recommendation and decides which flu strains to include in their flu vaccine.

“The influenza viruses in the seasonal flu vaccine are selected each year based on surveillance data indicating which viruses are circulating and forecasts about which viruses are the most likely to circulate during the coming season.”

CDC on Selecting Viruses for the Seasonal Influenza Vaccine

Although they don’t have a crystal ball and so can’t know exactly which flu strains will be making us sick each flu season, it is hardly a wild guess.

How often are they right?

“During seasons when most circulating influenza viruses are closely related to the viruses in the influenza vaccine, the vaccine effectiveness estimate has ranged from 50-60% among the overall population.”

WHO on Vaccine effectiveness estimates for seasonal influenza vaccines

Actually, they are right in most years! So if it is a guess, than the folks who choose which strains to include in the flu vaccine are very good guessers!

Except for a few years when their was a poor match, the flu season is typically between 37 to 60% effective.
Except for a few years when their was a poor match, the flu season is typically between 37 to 60% effective.

There have actually only been a few times in recent years when we have had mismatched flu strains. And in one of those years, they picked the right strain, but then the strain changed or drifted before the start of flu season.

“One hundred fifty-six (22%) of the 709 influenza A(H3N2) isolates were characterized as antigenically similar to A/Wyoming/3/2003, which is the A/Fujian/411/2002-like (H3N2) component of the 2004-05 influenza vaccine, and 553 (78%) were characterized as A/California/7/2004-like.”

2004-05 U.S. Influenza Season Summary

Not surprisingly, flu vaccine effectiveness goes way down during a mismatch year. During the 2004-05 flu season, for example, the overall vaccine effectiveness of the flu vaccine was just 10%.

Of course, in most years, flu vaccine is typically much more effective than that.

How effective will flu vaccines be this season?

Will this year’s flu vaccine be a good match?

We won’t know until flu season is well under way, not that you should wait for an answer to get your flu vaccine. The benefits of the flu vaccine extend beyond preventing the flu, so it is a good idea to get vaccinated even in a year when there might not be a good match.

More on Selecting Flu Vaccine Strains