Ask Harriet! Why two flu shots?
When we first started Rational Moms, I had this idea to do a weekly post called “Ask Harriet,” in which we would take advantage of the fact that Harriet Hall from Science Based Medicine offered to be a resource for us and answer random questions we might have. She still does answer questions for us, but the regular post thing sort of went out the window. Between working and having a kid, and actual writing deadlines that don’t have to do with this blog, I’m really happy if I have regular laundry. Or dinner. Plus, most of the questions Jessie and I have asked Harriet ended up being synthesized into longer posts that really were our writing.
But in this case, I think it’s best to just post Harriet’s answer. So here is the first, and possibly only, “Ask Harriet.”
From me:
Why do kids need two flu shots? And how much immunity is conferred, if any, from the first shot?
And the answer:
Why do kids need two shots? Because tests show they don’t develop adequate levels of antibodies from the first shot. They may get a low level of protection from the first shot, or they may get none at all. Adults probably respond better because they have prior experience with related strains of flu.
From the CDC website: http://www.cdc.gov/Flu/protect/children.htm “Children 6 months up to 9 years of age getting a flu vaccine for the first time will need two doses of vaccine the first year they are vaccinated. If possible, the first dose should be given as soon as vaccine becomes available. The second dose should be given 28 or more days after the first dose. The first dose “primes” the immune system; the second dose provides immune protection. Children who only get one dose but need two doses can have reduced or no protection from a single dose of flu vaccine. Two doses are necessary to protect these children. If your child needs two doses, begin the process early, so that children are protected before influenza starts circulating in your community. Be sure to follow up to get your child a second dose if they need one. It usually takes about two weeks after the second dose for protection to begin.”
Also see this:
http://www.reuters.com/article/healthNews/idUSKIM40117220070124With vaccines for different diseases, you may only need one shot or you may need a series to develop an adequate level of immunity. For instance, with Gardasil you need 3 shots 2 months apart. I guess it depends on the antigens used and how the body responds to them. I can’t really explain it on a
cellular level.Harriet Hall, MD
The SkepDoc
www.skepdoc.info
www.sciencebasedmedicine.org
If anyone does have the answer “on a cellular level,” I’d love to hear it. I couldn’t find it by searching around in Google U.
In any case, the answer is useful but a tad unnerving. It turns out my son won’t have full immunity against H1N1 until a couple weeks after that second shot. But what can we do? We can’t make him stay in the apartment all day. At least he will have immunity by the time we take a plane back east for the holidays.
I was also interested to learn that for the seasonal flu, kids only need two shots the first time around. So I’m going to ask our pediatrician if our son really needs the second seasonal shot this year, since he got two last year.
Squillo Said,
October 29, 2009 @ 6:13 pm
My daughter is likely only to get one H1N1 vaccination, due to shortages. (Her peds. office isn’t committing to the second dose for kids who, like my daughter, have gotten seasonal flu shots before.)
I’m wondering if the first dose is just a waste of scarce vaccine if she doesn’t get the second dose.
P.S. Am still waiting for the injectable to become available in my area for my son, who has asthma.
Harriet Hall Said,
October 30, 2009 @ 7:17 am
To clarify: if your child has had a flu shot in the past, only one shot is indicated this year.
Dana Said,
October 30, 2009 @ 10:52 am
Did anyone else hear the story on NPR this morning? The WHO has now said that only one shot is necessary for kids under 10. I guess the CDC is reviewing the findings. I’m really hoping this is true not just because I don’t want to get my son another shot, but because that means our kids already have immunity from one.
Laurie T. Said,
October 31, 2009 @ 12:08 pm
I’ve been told several times that, for the seasonal flu vaccines, the child only needs two doses that first year, then all subsequent years they only need one dose.
I’m concerned that my kids may not get the second dose, due to shortages as well. They aren’t doing a good job distributing the vaccine in our area, and people have begun to act crazy about it! My mother is an RN, and she volunteered all day yesterday to administer shots and mist. She said that people were upset and angry and there were shouting matches. At the vaccine clinic! One woman demanded that my mom give her a written guarantee that the vaccine wouldn’t make her sick. My mother told her that she assumed the woman had already decided to get the vaccine, or she wouldn’t have come out and stood in line, so maybe she should just go sit down and think it over. So, the woman did.
People think the vaccine will hurt them in some way, but then they go stand in line for hours to get the vaccine, and antagonize the volunteers when they get there. The whole situation is crazy!
Joy Said,
November 1, 2009 @ 5:12 am
I had both of my children vaccinated for H1N1 on Friday, and I was told they wouldn’t need a seasonal flu shot again in 2 weeks b/c they received it last year as well.
However, I am in the same position as the other mothers who have posted, my children will need a second dose of H1N1 in 2 weeks, and will likely not get it.
I was unaware that the first shot merely primed the system, I assumed there would be partial immunity in 10-14 days. If the first shot primes, but doesn’t give immunity, why is the World Health Organization now saying one dose is sufficient? It sounds to me like 1 dose isn’t enough, except in situations where there is a pandemic.
You shouldn’t give parents the impression that their childen are immune when they are not, so that you can help save vaccine for more people. We should be given accurate information. Tell us our children aren’t protected, but don’t blatantly lie. This whole situation is dispicable!
RHA Said,
November 1, 2009 @ 8:10 am
It’s not a matter of fudging things in order to stretch supplies, nor is it a “blatant lie”. You are jumping to conclusions about their motives. The WHO is a health organization that makes it’s recommendations after reviewing the science.
The statement that 1 dose is likely sufficient for children to develop immunity comes from the new data (via GlaxoSmithKline, producer of the Canadian adjuvanted vaccine) that is showing that 100% of children they’ve monitored have shown a positive immune response from a single dose. The children monitored were in the 6-36 month range and had th adjuvanted vaccine, which is recommended for children due to it’s greater effectiveness. My daughter got that shot and is 21 months, so I find this reassuring. I assume that the older a child is the stronger their immune system response – but that’s my assumption and I have no reference for it.
http://www.cbc.ca/cp/health/091030/x103002A.html
In any case, I believe the current recommendation by those actually administering the shots is still to get 2 for children under 10.
On a side note, there’s a useful H1N1 vaccination group here if someone hasn’t mentioned it already on this blog (I’m a bit behind):
http://www.facebook.com/groups.php?ref=sb#/group.php?gid=161444432417
molly Said,
November 2, 2009 @ 9:46 pm
We were lucky to get the first one (had to pester the office for weeks and then take a day off work to wait in line at 7 AM) and there’s really a very slim chance we’ll be able to get the second, which is sad, but, we had to try.
Is the WHO’s statement based on the canadian and european versions which are adjuvanted? That’s what I understood–the US versions are less efficacious at a single dose because of this difference in manufacture. A real bummer to be sure for those of us who only manage to scare up the first puzzle piece. Good luck to everyone seeking the shots!
RHA Said,
November 3, 2009 @ 12:32 pm
From what I’ve read the WHO statement is specific to the adjuvanted vaccine, which most countries are using. Unfortunately, in the USA recent data has shown that a single dose of the unadjuvanted vaccine doesn’t appear to be sufficient.
From a CBC article:
The U.S. National Institutes of Allergy and Infectious Diseases (NIAID) released clinical trial data Monday showing that children under 10 didn’t respond well enough to one dose of adjuvant-free H1N1 vaccine to consider them protected against the virus. Based on those data, the U.S. is sticking to its earlier recommendation that children under 10 get two doses of H1N1 vaccine, given at least 21 days apart.
Two Flu Shots Part Two Said,
November 3, 2009 @ 6:20 pm
[...] asked Harriet Hall why kids need two flu shots a few posts [...]
MERCY Said,
November 9, 2009 @ 11:55 am
I MOVED FROM LONDON TO THE U.S. FOUR MONTHS AGO,THE THING IS THAT MY CHILDREN WHO RANGE BETWEEN AGES 3 THRU 14 HAVE NEVER HAD A FLU SHOT BEFORE. THEY GOT THEIR SHOTS A MONTH AGO,AND I’VE BEEN TOLD THAT THE 3 OF THEM UNDER 8 WILL NEED SECOND DOSES,WHAT ABOUT MY 9 YEAR OLD? AND HOW EXACTLY DOES THIS WORK?
Julie Said,
November 14, 2009 @ 10:25 am
Mercy,
Children under 10 need two shots, given at least 21 days apart. About two weeks after the second shot, they should gain immunity. So according to the CDC recommendations your 9-year-old would need the second shot as well. But as always, I would say ask your doctor. Blanket recommendations are not as good as speaking to your physician.
christine metzner Said,
November 19, 2009 @ 10:13 am
hi…
my son whos 7 months old, got the 2 shot seasonal flu cocktail, then was to get the h1n1 shot… instead they gave him a 3rd seasonal flu shot by mistake… should i be worried?? what effects could this have on him…
thanks
worried mom
Julie Said,
November 21, 2009 @ 9:14 am
Christine, I wouldn’t worry. Ask your doctor, but I can’t think of a reason that an extra shot would hurt.