White Coat Underground

I love it when friends read my blog. Maybe it’s simple vanity, but I love being able to talk to people about what I’m writing. Readers who ask good questions (especially friends, because I trust their motives) help me reevaluate my message and my facts.

So an old friend sent me an email this weekend after reading a post, and it’s a question deserving of careful examination. It goes to the mixed messages physicians give to patients even when we don’t mean to.

I was anxious about vaccines and meted them out a little bit more slowly than is typical (only one or two at a time – just took more visits to get them done) but we did them all. Overall, I trust doctors to know a lot more about this stuff than I or any random website I might find telling me not to get them…. however, I always wondered why [pediatricians] advise only introducing one new food at a time, in order to identify the source of any reactions, but give a whole bunch of shots at once. (i’m sure you will have a good explanation for why my analogy is faulty!)

My friend is a mother, writer, and educator. If she doesn’t know the answer, it’s because we as physicians haven’t communicated it well (or because we didn’t anticipate the question!). Sometimes as physicians we err too far on the side of paternalism and expect patients to simply follow our advice without explanation. This is a mistake.

As a parent, the question makes sense to me. There is nothing that concerns me more than my child’s welfare, and seeming inconsistencies in recommendations are going to make me anxious. Often, conflicting health advice is the result of conflicting evidence. I had a patient a couple of years ago who said, “All the doctors are telling me something different. How do I know which one is right?” I told her, “They can fight about it all day, but that’s why we got the biopsy. That will get us the answer.”

The fact that there are uncertainties in medicine does not take away from the validity of medicine. Being able to say, “I don’t know” is essential to any scientific practice.

But what about my friend?

Food allergies are relatively common. The exact reason for this ins’t yet clear, but there are several hypotheses. One is the so-called “hygiene hypothesis” which posits that our hyper-vigilance is hurting our kids. Every time we hold back on exposing our kids to new substances, every time we sterilize a pacifier, we may be preventing important modifications in the immune system—or so it is hypothesized. Really, no one knows yet.

Given the prevalence of food allergies, many pediatricians recommend adding new foods one at a time so that if the child experiences a reaction it might be easier to figure out which food might be responsible. It’s not clear to me that the evidence supports this approach but that’s the way things are currently done.

Vaccines are not associated with significant rates of adverse events.  Because reactions are so rare, there is no reason to introduce vaccines in the same way we do with new foods.  Also there are a host of positive reasons to introduce vaccinations at certain times, based on risks of exposure and disease, whereas with food, as long as a child is getting sufficient nutrition, no single food is critical.   

The science isn’t clear on when and how to introduce foods, but given the frequency of food allergies, caution seems reasonable (unless of course that approach is actually exacerbating the problem, but that doesn’t seem terribly likely).  The science is quite clear about the safety and efficacy of vaccines and of the current vaccination schedule, so there is no reason to change the way we vaccinate based on current data.  


  1. #1 homeshuling
    January 4, 2010

    Thanks, Peter!

    The ironic thing is I didn’t even follow the advice about foods….

  2. #2 katydid13
    January 4, 2010

    Illegal raw milk from a small Amish farm has become all the rage among some of my friends for the upwardly mobile DC toddler because supposedly it can prevent milk allergies. They think because it’s just this one farmer and he knows his cows that there is little risk. Can you suggest a resource I can point them to that would point out how dangerous this is without making it seem like I’m calling them bad parents?

  3. #3 Vince Whirlwind
    January 4, 2010

    Our approach was to stick with breast milk only for as long as possible and steer well clear of milk and bread until 12 months.
    We started with rice porridge, then pumpkin mash. Our first one didn’t demand solids much before 6 months, but our second one was desperate for them by about 4 months.

  4. #4 Kemist
    January 4, 2010


    Well, I have found that paper :

    Two outbreaks associated with raw milk consumption

    The interesting thing is that both the infected groups became ill after drinking raw milk on a farm they were visiting, and that the bacteria (exact same strain) could be detected in them and in the cows, including their feces, but not in the reservoir that contained the milk.

    That means that it would have been be very difficult to know the milk is contaminated with routine tests. And, needless to say, “knowing the cows” does not at all protects you against contamination.

  5. #5 Vince Whirlwind
    January 4, 2010

    I should say, I gave my 3rd one some hummous once, when she was about 6 months old (she was very insistent) and she immediately reacted with a red and swollen rash all over her lips, chin, cheeks, just like a really bad board-rash.

    None of them have developed any food allergies though. We have never over-invested in cleaning products…:)

    I have to pay them to make them eat brussel sprouts, asparagus or oysters; they are extremely reluctant to eat chocolate; and nothing will make any of them eat tomatoes.

    Incidentally, anyone see the recent “Bonsoy” soymilk iodine poisonings in Australia?
    One of those affected was an infant.
    Like the “upwardly mobile DC toddlers” mentioned above, it seems some bright spark thinks they should be feeding soymilk to an infant. Cretins.


  6. #6 Interrobang
    January 4, 2010

    it seems some bright spark thinks they should be feeding soymilk to an infant. Cretins.

    I probably would have been much happier, and certainly had fewer digestive problems, if someone had fed me soymilk instead of cow’s milk when I was an infant. Adoptees, with possible minutely rare exceptions, don’t get breast milk in this culture, and I lost my lactose tolerance sometime before 1 year of age. Soymilk has a lot of nutrients in it that are otherwise hard to get in a northerly climate and on an infant’s restricted diet.

  7. #7 Liz Ditz
    January 4, 2010

    Granny Liz here.

    I distinctly remember my mother adhering to the “one new food a week” regimen in 1960 with my youngest sister. It may be a Spock recommendation, for all I know. (The memory is because I fed her some applesauce before it was on the rota.) It was also recommended in 1978 for my oldest son, who had had allergies to formula in his infancy. And I followed it in 1989 when adding solid food to my daughter’s diet.

    Here’s a thought from my lay mind:

    however, I always wondered why [pediatricians] advise only introducing one new food at a time, in order to identify the source of any reactions, but give a whole bunch of shots at once.

    What many non-vaccinologists don’t know is that many (most?) modern vaccines contain only fragments of the thing they are meant to cause immunity to — just enough to provoke an immune response. Plus of course the vaccines, even in combination, have been extensively studied for both efficacy AND safety.

    However, your basic banana (or squash, or rice porridge or whatever food you are introducing) is a conglomeration of many, many substances — some of which may cause a reaction, allergic or otherwise.

    An example of “otherwise” might be my own reaction to raw spinach. About 1/4 cup mixed in with other leafy greens, no problem. As little as 1/4 c. plain….GI distress.

    That brings up the whole the dose-response notion, especially in relation to your friend’s worry about “too many vaccines at once” vs. food. The vaccines introduce micrograms (I think) vs. new foods, which are introduced at the (10s of grams) level.

  8. #8 Katherine
    January 4, 2010

    Just to weigh in on the allergies: both my parents have quite a few allergies, and my dad is allergic to milk. When I was born apparently the nurses in the hospital didn’t check for family history of allergies, and gave me cows’ milk. I’ve never had a reaction to anything (except once some drug I was given for my tonsilitis, that hasn’t happened again and it was only mild). My sister on the other hand has most of the allergies that my dad has.

    But then I also used to eat clay when I was a toddler so that might have helped too.

  9. #9 WMDKitty
    January 4, 2010

    Speaking of allergies, does anyone know why they get better (or, as with mine, worse) with age?

  10. #10 Skeptico
    January 5, 2010

    Presumably the other difference is the risk/reward calculation: there is no risk in delaying giving your child one type of food; the risk in delaying a vaccination is that your child might get sick.

  11. #11 Rev Matt
    January 5, 2010

    We have never been great about the ‘one new food at a time’ approach and thus far have not had any problems. While in China meeting our adopted daughter we gave her all sorts of things that are verboten here in the US for kids under a year (strawberries, fish, eggs, etc). Her only issue was overeating as a reaction to finally having more food available to her than she’d ever had before.

  12. #12 khalihs
    January 5, 2010

    @4 Would it be safe to hypothesize that the reason why the bacteria is not detected in the vessel, but is in both biological hosts, is that the bacteria requires a living entity in order to propogate into a quantity detectable by available routine methods…?

    Just because you can’t detect something outside of its host environment, doesn’t mean that it isn’t there.

    It’d be like my idiot friends who think that just because they kept boxes of clothes outside in the freezing cold for 2 months, and that got rid of the cockroaches, that means the cockroach eggs were killed by the freezing cold. This despite evidence to the contrary by both entymologists and the presence of cockroaches in their house since bringing said boxes inside… who says an education beyond high school is recommended…?

  13. #13 Beth
    January 5, 2010

    I don’t know how pediatric vaccination is accomplished, but when I got the flu vax and the pneumonia vax at the same visit, the nurse wouldn’t inject them into the same muscle — so that any local reaction could be easily identified, the nurse said. I’m not sure if that’s standard procedure in general, standard procedure of just that practice, or if it’s just her. I was in a vaccine study a while back and the nurse did give me two vaccines in the same general area but one was intramuscular and the other subcutaneous, so that might make a difference, too. I wonder if there is any standard procedure for multiple vaccines or if it’s just whatever different nurses do.
    Then again, often the “rules” are merely guidelines and it just takes some pushing to get something different. I had a bad local reaction to a flu vax years ago such that left me with little use of my arm for over a week. That mightn’t be so bad but that I have mobility problems such that I need my arms. After that, I’ve had my shots in my thighs but I have to recount my reaction to get them that way.
    – Can I have the shot in my leg?
    – No, we don’t do that. We only give this vax in the arm.
    – I’ll get it in my arm if I have to, but last time… [recount story]
    – Ok, you can get it in your leg.
    I’ve taken to telling the story outright as the reason I’m asking, but I really don’t like how some nurses talk like they couldn’t possibly give shots how I request, say they can only give it a certain way but then, upon hearing my tale, quickly change their tune. I can’t trust someone who’ll lie to me. I have no idea what “rules” about vaccines are for physiological reasons and not just what we do. Like which muscle, as far as I can figure, there’s no real reason for that but that arms are convenient and that most people’s lives will not be impeded by some potential soreness there. I don’t know if the “rule” about no two vax in the same muscle is for good reason. (How much do local reactions matter? Injecting different muscles likely wouldn’t help identify the culprit of systemic reactions.) I wish I could find something or someone I could trust regarding the rules/guidelines and the reasons for them.

  14. #14 gaiainc
    January 5, 2010

    Beth, I think that nurses, like most humans, get into a routine and when that routine gets disturbed, feathers are ruffled. Infants routinely get their vaccines in their thighs (greater muscle mass and in some ways easier to pin down than arms). Actually, except for the Hep B and the rabies vaccine, it doesn’t matter so much if the vaccine is given subcutaneously or intramuscularly (I asked the CDC as it came up in clinic).

    I think Liz Ditz has identified a fundamental difference between vaccines and food. Vaccines are purified antigens. Food is an amalgam of hundreds of antigens. Big difference.

    My son basically had a taste of everything that his father and I eat except for honey by the time he was one years-old. He used to eat a lot more variety than he does now, but he’ll still scarf down asparagus, green beans, beets, and chicken tikka marsala. When I advise new parents now, I still advise one food/taste at a time. However, the only food I tell them that the baby cannot have is honey. Everything else, over time, is fair game I think.

  15. #15 James Sweet
    January 5, 2010

    Great answer, thanks!

  16. #16 Kemist
    January 6, 2010

    @4 Would it be safe to hypothesize that the reason why the bacteria is not detected in the vessel, but is in both biological hosts, is that the bacteria requires a living entity in order to propogate into a quantity detectable by available routine methods…?

    Normally you do not need the host to propagate bacteria, but a culture media – that is the basis for routine tests, including those that were made from sample from the coys.

    I think what it means is that:

    1) Campylobacter jejuni is highly infective – it takes a very small load to infect humans, since 86% of those who drank the milk developped the infection, and these were healthy adults;

    2) The milk was not contaminated after extraction (as so many websites vaunting the qualities of raw milk like to expound as the only way milk could be contaminated), but from the cows themselves;

    3) The cows were asymptomatic carriers.

    Milk is a secretion that comes from a living animal and therefore can carry the germs from the infected animal to the drinker – that is pretty much clear for human milk, and I don’t see why it would be different for cow’s milk. The added danger here is that what makes a human sick does not necessarily makes a cow sick. So, even if you have your own cow in your backyard, you would not know the milk was contaminated until you got sick. Unless you also happened to have a microbiology lab.

    What rosy pictures are painted by the “health food” raw milk proponents is not reflected in peer reviewed litterature, that is, in reality. Unfortunately (because I do enjoy raw milk for its taste) the risk is very real.

  17. #17 Gaythia
    January 6, 2010

    Parents who themselves suffer from severe allergies are well trained on the allergy regimen of introduce sequentially, investigate carefully, and are not inclined to experiment otherwise with babies.

    For vaccines, it should be noted that the product guidelines themselves say you should watch for allergic symptoms. If a parent wishes to ensure that they can give their child as many vaccines as possible it is highly desireable to isolate any allergic cause to one shot in particular, so as not to knock out the possibility of getting further doses of other vaccines. This is actually a strongly pro-vaccine stance.

    It is not likely the vaccine itself that one would be allergic to, but rather the media the vaccine was developed in or the carrier. Frequently once such an allergen is identified, it is possible to deliver the vaccine using some other formulation.

    Also, in the process of discussing vaccination schedules with ones pediatrician other issues can be identified. For example, I was advised (long time ago) to avoid a volunteer activity that would have potentially exposed my infant to whooping cough well before the time when vaccination for this is given. I would imagine that ,at least in some parts of the country, this would be even more of a problem now than it was then.

  18. #18 daedalus2u
    January 6, 2010

    My understanding is that for an allergic reaction you need both an exposure that sensitizes the immune system and a second exposure that causes the allergic immune reaction from that sensitized immune system. The reason for adding one food at a time is so that the food causing the allergic reaction can be more easily identified and eliminated from the diet.

    In the case of vaccines, the whole purpose of vaccination is to sensitize the immune system and produce a robust immune response. Each different vaccine is different, and to a very large extent they don’t interact immunologically. The immune system can easily handle 10,000 antigens simultaneously, and does because natural substances (such as food or non-sterile things like dirt) contain many different antigens. Vaccines are only given once (except for those that don’t produce a good response with one dose) so the presence of a reaction isn’t a reason to not give a second dose (because second doses usually are not given anyway).

    The only benefit to introducing one food at a time is that if there is a reaction the food that produced it can be easily identified. If you introduced multiple foods simultaneously, figuring out which one caused the reaction will be more difficult and getting an infant used to eating strange new foods might be more difficult if stuff is added and subtracted at high rates. As long as the infant is getting enough nutrition, what foods are involved is a detail. Giving the infant digestive system time to adapt to new foods is likely a good idea independent of any immunological considerations. They are all a little bit different, and presumably require a little bit different digestive process which needs to be controlled a little bit differently. It has to take some time for that adaption to occur.

  19. #19 becca
    January 6, 2010

    “Each different vaccine is different, and to a very large extent they don’t interact immunologically. “
    That’s always been the assumption, but I’m not so sure.

    “The immune system can easily handle 10,000 antigens simultaneously, and does because natural substances (such as food or non-sterile things like dirt) contain many different antigens.”
    Very true. And extremely high frequency antigens, and those entering through the gut, tend to train the immune system toward tolerance rather than robust B cell/T cell responses that can result in immunological memory. Which is why I wonder.
    On the other hand, they’ve just finagled a strain of wolbachia to infect mosquitoes to train their innate immune systems to fight off plasmodium. So maybe simultaneous exposure would *enhance* the efficacy of immune responses.
    As an immunologist, I’m very ambivalent about giving my child all the vaccinations in large batches. It could be better to do them one at a time or worse.

    “Vaccines are only given once (except for those that don’t produce a good response with one dose) so the presence of a reaction isn’t a reason to not give a second dose (because second doses usually are not given anyway)”
    False. Look up the CDC’s recommended childhood vaccination schedule.

  20. #20 PalMD
    January 6, 2010

    Becca, from a bigger picture perspective, the vaccination schedule, independent of immunologic theory, has been shown to be very safe and very effective. While on the micro level there are certainly interesting questions, in the big picture of medicine and public health, there really aren’t a whole lot of problems at this point.

    I’ve seen no evidence that would deter me from following expert rec’s on vaccination.

  21. #21 becca
    January 6, 2010

    Oh I don’t doubt it’s safety or efficacy. I doubt it’s *efficiency*. That is, could it be further optimized? It’s entirely a *good* question for immunology theory.
    Furthermore, when my pediatrician suggests, without input from me other than “my child had an adverse reaction (projectile vomiting the likes of which I have seen neither before nor since)”, breaking up the immunizations into multiple trips, is my best bet to follow their advice or to adhere as strictly as possible to the CDC vaccination schedule? When I cannot for the life of me understand a recommendation (e.g. hep B vaccination a day after birth), is it worth trying to argue with Carebear if he wants to delay a vaccination?
    I’m an immunologist. I get paid to wonder about this kind of stuff. I’m also a parent, and there’s a practical question here as well.
    That said, I will formally explicitly state it for record: NO ONE should read my idle ponderings and take that as a reason to doubt that vaccination is safe and effective.

  22. #22 Gaythia
    January 8, 2010

    In my opinion, the schedule is optimized for efficiency. It is more efficient to give multiple vaccines at once. It is more efficient for the office clerk to routinely schedule office visits by the calendar age of the baby rather than have medical professionals be concerned about relative aspects of development or overall health. It is more efficient to immunize all babies for Hep B than to worry about how to locate and focus on the few babies (and their mothers) that might be at risk at that time.

    We also have a legal and insurance culture that is based on the idea that if everybody does that which has been labeled “normal and customary” then everything is golden.

    How do you deal with what is efficient for a society as opposed to what is efficient for an individual?

  23. #23 daedalus2u
    January 8, 2010

    Giving multiple vaccines at a time also reduces child mortality due to automobile accidents due to more automobile travel time for multiple single-vaccine office visits.

    If the travel distance is more than a few miles, the risk of travel to the office may exceed the risk due to the vaccine.

  24. #24 MCoenen
    January 9, 2010

    It seems that there is a vast reservoir of data on multiple vax. I remember receiving what seems to be up to 10 vaccinations at one time. In basic training we walked down a gauntlet of medics with air injectors. This was 40 years ago and I think it is the current practice Has this data been mined?

  25. #25 Khalihs
    January 10, 2010

    I appreciate the more detailed explanation. My hypothesis was based on your notes that by said normal testing methods, the bacteria was detectable in the cows and the humans, but not in the container. So I was looking for a reasonable explanation, that includes the presence of the bacteria in all three ‘containers’, for why only the fleshy, living containers were detected as having the bacteria.

    If the bacteria were not viable outside of a living host, ie “dead”, wouldn’t that keep them from growing in a media dish?

    It’s been almost 20 yrs since my directed study in a Micro lab, so my exposure to the topic is limited.

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