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.
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.
- 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.”
- 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.”
| Year | Flu Virus Strain | VE |
| 2004-05 | A(H3N2) | 10 |
| 2005-06 | A(H3N2) | 21 |
| 2006-07 | A(H1N1) | 52 |
| 2007-08 | A(H3N2) | 37 |
| 2008-09 | A(H1N1) | 41 |
| 2009-10 | A(H1N1)pdm09 | 56 |
| 2010-11 | A(H3N2) | 60 |
| 2011-12 | A(H3N2) | 47 |
| 2012-13 | A(H3N2) | 49 |
| 2013-14 | A(H1N1)pdm09 | 52 |
| 2014-15 | A(H3N2) | 19 |
| 2015-16 | A(H1N1)pdm09 | 48 |
| 2016-17 | A(H3N2) | 40 |
| 2017-18 | A(H3N2) | 40 |
| 2018-19 | A(H1N1)pdm09 | 47 |
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
- The 2019-20 Flu Season Update
- I’m Not Anti-Vaccine, I Just Don’t Believe in Flu Shots
- Do They Really Just Guess at Which Strain to Put in the Flu Vaccine?
- Does Getting a Flu Vaccine Increase Your Risk of Spreading the Flu or Getting Others Sick?
- What Makes the Flu So Deadly?
- Does the flu shot contain a vaginal spermicide?
- Can Flu Shots Cause the Flu?
- Why Do Some Folks Wear a Mask During Flu Season?
- Do They Really Just Guess at Which Strain to Put in the Flu Vaccine?
- I Refuse to Listen to Bad Advice About Flu Shots, and I Won’t Apologize for It
- MMWR – Interim Estimates of 2018–19 Seasonal Influenza Vaccine Effectiveness — United States, February 2019
- CDC – Vaccine Effectiveness – How Well Does the Flu Vaccine Work?
- CDC – Interim Estimates of 2017–18 Seasonal Influenza Vaccine Effectiveness — United States, February 2018
- Study – Late season interim estimates of influenza vaccine effectiveness reliably predict end of season estimates in Victoria, Australia, 2007 to 2012.
- CDC – Preliminary In-Season U.S. Influenza Burden Estimates
- CDC – Situation Update: Summary of Weekly FluView Report
- CDC – Age Group Distribution of Influenza Positive Specimens Reported by Public Health Laboratories, National Summary, 2018-19 Influenza Season through the Week Ending January 05, 2019
- CDC – What are the benefits of flu vaccination?
- CDC – Seasonal Influenza Vaccine Effectiveness, 2004-2018
- CDC – Preliminary Estimates of 2017–18 Seasonal Influenza Vaccine Effectiveness against Laboratory -Confirmed Influenza from the US Flu VE and HAIVEN Networks
- Ask the Experts about Flu Vaccines
- No, the CDC did not just apologize and admit that this year’s flu vaccine doesn’t work
- No, the CDC did not just apologize and admit that this year’s flu vaccine doesn’t work, part 2