Thursday, September 29, 2016

CDC urges Americans to get a flu shot as soon as possible/ NPR

NPR tells us influenza vaccine comes in twelve flavors this year.  You can pick 3 antigens or 4.  With or without a squalene adjuvant? (Fluad is the first US vaccine to use the MF59 squalene adjuvant, though its manufacturer worked to get it into the US market for almost 2 decades.)  High dose or regular strength? Made in armyworm cellsdog kidney cells, or just the usual egg-based vaccine?

Sorry--the nasal spray flu vaccine (FluMist by AstraZeneca) is not recommended this year, since it didn't work the last three years.

CDC is concerned that fewer elders got flu shots last year.  Maybe that is because they, or their doctors, finally learned that there is no reliable evidence flu shots work in those over 65. Also see this.  (They do work to a degree in younger adults and older children.)

I averaged the efficacy results for the last 12 years, from CDC's website and an MMWR report for the 2008-9 seasonal flu vaccine, since CDC had omitted that (negative efficacy) year from its list. Using CDC's own data, the average efficacy of flu shots (how well they work in controlled clinical trials, which may be better than their real life efficacy) was a whopping 37%.

So if 5% of the population gets flu each year without being vaccinated, only 3 or 4% will get the flu when everyone is vaccinated.

As the Cochrane Collaboration noted in a 2014 review of this subject (one of many they have done) you would need to vaccinate 71 people to prevent one case of flu.

Got it?  Now go get your shot.

P.S.  There are 80 million American children.  Last year, there were 85 influenza-associated deaths in children, or one in a million.  We have no idea how many children suffered serious side effects from influenza vaccines.  We have no idea how many suffered side effects from FluMist, which gave them no protection.  Fifteen million doses of Flumist were delivered to the US market last year, at a cost of about $23 each, or $350 million total.  Nice work if you can get it.


Anonymous said...

So, are you against the flu shot on the grounds that, in aggregate, it doesn't do much?

Just that, as a layman, 37% effectiveness rate doesn't seem all that bad. If it was a more serious illness, e.g., cancer, I'd certainly be pretty excited at a 37% chance to not get it.

But even with the flu, on an individual basis, having 37% less chance of getting it doesn't seem all that bad to me. But I understand that in the aggregate, it may not move the needle.

Meryl Nass, M.D. said...

I gave you the numbers and the age groups that benefit so you could make your own decision whether it is in your best interest to get a flu inoculation.

I feel it is my job to balance risk and benefit. It is hard to do that when, as in the case of influenza vaccines, you cannot quantify risk.

I know that every shot is unique and every person is unique. The reason we have doctors is to try and help patients use available information to make appropriate decisions for themselves.

Anonymous said...

Thank you. That makes sense.