# How many vaccines can safely be administered in one day? **URL:** \ **Category:** Factual Questions\ **Created:** [February 8, 2015, 11:33am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108 "2015-02-08T11:33:16Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [February 8, 2015, 11:33am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/1 "2015-02-08T11:33:16Z")
Let’s say that someone received many, many, many different vaccination injections in one day. Obviously, this would be an unwise thing to do, but let’s say it happened. What would be the effect on his body? Would his immune system be overwhelmed? Would the dozens of injections interfere with each other other or create side effects? ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [February 8, 2015, 11:54am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/2 "2015-02-08T11:54:22Z")
> [@Velocity](#): > > Obviously, this would be an unwise thing to do No, there’s nothing obvious about it. ---
**Author:** ![Ambrosio\_Spinola](https://avatars.discourse-cdn.com/v4/letter/a/9de0a6/32.png) [@Ambrosio\_Spinola](https://boards.straightdope.com/u/Ambrosio_Spinola)\ **Post date:** [February 8, 2015, 1:38pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/3 "2015-02-08T13:38:34Z")
Researcher Paul Offit suggests that you could get [10,000](http://www.sciencedaily.com/releases/2002/01/020109073542.htm) vaccinations at once without overtaxing your immune system. My guess is that people vastly underestimate both how many and how many kinds of micro organisms they encounter on a daily basis. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 8, 2015, 1:48pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/4 "2015-02-08T13:48:38Z")
The [CDC’s](http://www.cdc.gov/vaccinesafety/Vaccines/multiplevaccines.html) statement on the subject: > [@](#): > > The available scientific data show that simultaneous vaccination with multiple vaccines has no adverse effect on the normal childhood immune system. A number of studies have been conducted to examine the effects of giving various combinations of vaccines simultaneously. These studies have shown that the recommended vaccines are as effective in combination as they are individually, and that such combinations carry no greater risk for adverse side effects. … > > … No evidence suggests that the recommended childhood vaccines can “overload” the immune system. In contrast, from the moment babies are born, they are exposed to numerous bacteria and viruses on a daily basis. Eating food introduces new bacteria into the body; numerous bacteria live in the mouth and nose; and an infant places his or her hands or other objects in his or her mouth hundreds of times every hour, exposing the immune system to still more antigens. When a child has a cold they are exposed to at least 4 to 10 antigens and exposure to “strep throat” is about 25 to 50 antigens. The simple facts are that each immunization contains only a handful of things that the body will be responding to, critical things to respond to be sure, but just a handful. Regular life in the real world has us responding to many more every day. The effect on the body would be protective responses to the germs being vaccinated against and the same likelihood of sore muscles etc. as when they are given separately. No it would not overwhelm the immune system nor, assuming following guidelines on separate locations, interfere with each other or create other side effects than they do as stand alone immunizations. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 8, 2015, 1:51pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/5 "2015-02-08T13:51:32Z")
When I was in the service we used to get a bunch of vaccinations at once. Like 4 or 5. Some of which were themselves combinations such as the TDAP (Tetanus, Diptheria, & Pertussis). It didn’t seem to cause anybody any obvious problems. Although this was administered to a young healthy cohort. Doing the same thing to a nursing home full of grannies might not work as well. ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [February 8, 2015, 1:57pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/6 "2015-02-08T13:57:56Z")
> [@LSLGuy](#): > > Doing the same thing to a nursing home full of grannies might not work as well. Why not? ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [February 8, 2015, 2:46pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/7 "2015-02-08T14:46:36Z")
Vaccines are just a tiny extra challenge to the immune system. We’re constantly bathing in a world of bacteria and viruses trying to establish a foothold, so a few extra are not going to overload the system. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [February 8, 2015, 3:43pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/8 "2015-02-08T15:43:32Z")
> [@Northern\_Piper](#): > > Why not? Same reason you don’t give cancer patients certain immunizations - people who have or are likely to have compromised immune systems are at risk of adverse effects from certain vaccines. Elderly people are more likely to have immune system problems due either to illness, various medications, or just the fact that when you’re really old nothing works as well as it used to. That doesn’t mean you can’t vaccinate a particular elderly person, or even most elderly persons, it’s just that they’re a group that might need more intense looking at before proceeding to find vulnerable individuals. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 8, 2015, 4:15pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/9 "2015-02-08T16:15:15Z")
In real life the major problem with vaccinating the elderly and their older immune systems is not bad reactions to vaccines but _insufficient_ reactions to them. ---
**Author:** ![Alley\_Dweller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alley_dweller/32/430_2.png) [@Alley\_Dweller](https://boards.straightdope.com/u/Alley_Dweller)\ **Post date:** [February 8, 2015, 8:22pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/10 "2015-02-08T20:22:26Z")
Centers for Disease Control and Prevention, [Travelers’ Health.](http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-2-the-pre-travel-consultation/interactions-among-travel-vaccines-and-drugs) > [@](#): > > INTERACTIONS BETWEEN VACCINES > > In general, concomitant administration of multiple vaccines, including live attenuated immunizations, is safe and effective. Administering a live-virus vaccine within 4 weeks after administration of another live-virus vaccine can decrease immunogenicity to the second administered vaccine. This observation has given rise to the recommendation that live-virus vaccines should be administered the same day or ≥4 weeks apart. If the 4-week span is not achievable, the second vaccine may be administered sooner to afford some protection, but it should be readministered ≥4 weeks later if the traveler is at continued risk. A recent study examining concurrent administration of the yellow fever vaccine with the measles-mumps-rubella (MMR) vaccine in 12-month-old children showed slightly reduced immunogenicity to yellow fever and mumps components, compared with responses following separate vaccination with MMR and yellow fever vaccine 30 days apart. The clinical significance of this finding is uncertain at present. ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [February 8, 2015, 9:09pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/11 "2015-02-08T21:09:46Z")
> [@Ambrosio\_Spinola](#): > > My guess is that people vastly underestimate both how many and how many kinds of micro organisms they encounter on a daily basis. They should read, or at least see the movie, War of the Worlds. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [February 9, 2015, 1:53am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/12 "2015-02-09T01:53:07Z")
> [@Northern\_Piper](#): > > Why not? Because grannies fight back? ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [February 9, 2015, 10:13pm UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/13 "2015-02-09T22:13:35Z")
Anecdote: when I moved to a new school district in a different state between 9th and 10th grade, my entire immunization record somehow got lost or misplaced. To attend school, I had to get the entire recommended series of immunizations, starting with the ones normally received at birth. (I then had to return for the follow-up boosters at the recommended intervals.) The whole process took over a year. Anyway, the point of the story is that I got _numerous_ vaccinations simultaneously. Also, I kept track of my own shot record thereafter. ---
**Author:** ![sunstone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunstone/32/3372_2.png) [@sunstone](https://boards.straightdope.com/u/sunstone)\ **Post date:** [February 10, 2015, 3:29am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/14 "2015-02-10T03:29:49Z")
I only have anecdotal experiences to share, but I can tell you that I received 12 shots at a time while being readied for world-wide deployment status in the USAF during the '60s. The interval as I recall was about 3 months until the next barrage of 12 shot were given. I think that I was done before a year was completed. I have not contracted equine encephalitis, yellow fever or any of the other diseases since ------and the vaccinations did not have any adverse effects except for soreness at the injection site. ---
**Author:** ![DinoR](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dinor/32/2821_2.png) [@DinoR](https://boards.straightdope.com/u/DinoR)\ **Post date:** [February 10, 2015, 3:38am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/15 "2015-02-10T03:38:44Z")
> [@sunstone](#): > > I have not contracted equine encephalitis, yellow fever or any of the other diseases since ------and the vaccinations did not have any adverse effects except for soreness at the injection site. This made me think of a conversation I was part of getting shots pre-deployment. After talk of how many we were each getting stuck with as we waited in line there was one that we were all getting that prompted a question along the lines of: “Does anybody even know what this disease does?” Answer: “I don’t know but it sure sounds like something I don’t want to catch.” ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [February 10, 2015, 3:43am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/16 "2015-02-10T03:43:59Z")
Years ago, when I was in a student tour group preparing to go overseas, our advisor took us down to the health department free clinic and told them to give us everything they had – yellow fever, typhoid, polio, DPT, and so on. Other than an extremely large bump on our arms for the next day or two, no one had any adverse reactions. ---
**Author:** ![j666](https://avatars.discourse-cdn.com/v4/letter/j/9de0a6/32.png) [@j666](https://boards.straightdope.com/u/j666)\ **Post date:** [February 10, 2015, 3:55am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/17 "2015-02-10T03:55:02Z")
> [@Velocity](#): > > Let’s say that someone received many, many, many different vaccination injections in one day. Obviously, this would be an unwise thing to do, but let’s say it happened. > What would be the effect on his body? Would his immune system be overwhelmed? **Would the dozens of injections interfere with each other** other or create side effects? I think the bolded section is a valid question (1). If the immune system can focus on one antigen at a time (pardon the anthropomorphizing), will it generate a more robust immunity to each? I think it would be hell to put parents through getting the kids all their vaccinations 4 to 6 weeks apart, though. ETA: (1) As Alley Dweller’s post suggested. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 10, 2015, 4:13am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/18 "2015-02-10T04:13:42Z")
And answered. See the quote provided in post 4 and the link provided in post 3. The immunizations are “as effective in combination as they are individually.” Please realize that one dose of the old small pox vaccine, _by itself_ contained more antigens than _the complete immunization series today_ contains. Alley Dweller’s post is specific to _live virus vaccines_ (a relatively small number of possible vaccines) and notes that the slight difference in the response to yellow fever simultaneous to the MMR in comparison to at least a month apart is of no known clinical significance. ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [February 10, 2015, 4:34am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/19 "2015-02-10T04:34:45Z")
> [@LSLGuy](#): > > When I was in the service we used to get a bunch of vaccinations at once. Like 4 or 5. Some of which were themselves combinations such as the TDAP (Tetanus, Diptheria, & Pertussis). > > It didn’t seem to cause anybody any obvious problems. Although this was administered to a young healthy cohort. Doing the same thing to a nursing home full of grannies might not work as well. Just to say it, they had wrestling mats on the floor of the next room, to catch the squeamish. ---
**Author:** ![j666](https://avatars.discourse-cdn.com/v4/letter/j/9de0a6/32.png) [@j666](https://boards.straightdope.com/u/j666)\ **Post date:** [February 10, 2015, 11:58am UTC](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108/20 "2015-02-10T11:58:44Z")
> [@DSeid](#): > > And answered. See the quote provided in post 4 and the link provided in post 3. The immunizations are “as effective in combination as they are individually.” Please realize that one dose of the old small pox vaccine, _by itself_ contained more antigens than _the complete immunization series today_ contains. > > Alley Dweller’s post is specific to _live virus vaccines_ (a relatively small number of possible vaccines) and notes that the slight difference in the response to yellow fever simultaneous to the MMR in comparison to at least a month apart is of no known clinical significance. Posts 3 and 4 address **harming** the immune system in some way, don’t they? Not if the immune response would be better, somehow? Right now, some vaccinations fail and we need boosters; many people feel a little off for several hours after their multi-shot vaccinations. So, I think it is valid to wonder if a child might not benefit from an extended vaccination schedule, particularly an only child at no particular immediate risk and with a stay at home parent. I don’t think questioning standard medical practice automatically puts one in the Wakefield-McCarthy camp. And I do see on a more careful reading your link does touch on the issue, but I really don’t want to claw through the “number of studies”\* in your earlier reference to evaluate the criteria for vaccination effectiveness or statistical tests used, because I think it doesn’t really matter - the logistics of giving each vaccine four to six weeks apart in a relatively short window, with most doctors’ office hours and office visit costs would probably drive down compliance. I just think it was a valid question. - I use quotation marks because I am quoting, not to imply doubt on my part or anything. And I have to read a lot of studies and articles as it is, and I admit I do not know enough to determine if statistical tests used are appropriate to the data. [Next page](https://boards.straightdope.com/t/how-many-vaccines-can-safely-be-administered-in-one-day/712108.md?page=2)