Part Two / The First Year
Vaccination: Yes, Please
Vaccine safety, effectiveness, common concerns, and timing.
In this note
The one thing to remember
This is the least ambiguous chapter in the book. Vaccines prevent serious disease, the serious risks are extremely rare, and the autism claim originated in fraud. Delaying the schedule provides no demonstrated safety benefit and leaves your child unprotected for longer.
Important
Vaccine products, schedules, and contraindications change. Confirm timing and post-vaccine care with your child's clinician rather than the book's 2019 schedule.
Cutting through the noise#
Most of Cribsheet is about decisions where the data doesn't pick a winner and your preferences should. This one isn't like that. Oster's title gives away the conclusion, and the chapter is unusually one-sided because the evidence is.
That said, the reasoning still matters, because the anti-vaccine argument isn't usually "vaccines don't work." It's a set of specific, plausible-sounding worries. Understanding why each one fails is more useful than being told the conclusion — especially if you're going to talk to a relative about it.
The one genuine measurement problem: truly rare events are hard to quantify even in enormous datasets. If something happens in 1 in 5 million doses, you need tens of millions of records to see it clearly. That's a real limitation, and it's also why the answer to "but how can you be sure?" is that certainty isn't available for anything — including the diseases, which we can measure very well and which are unambiguously worse.
The 60-second recap#
- Vaccination dramatically reduced illness, hospitalization, disability, and death from diseases that used to be routine.
- No medical intervention is literally risk-free; serious vaccine reactions are extremely rare and clinics are equipped for them.
- Fever and febrile seizures happen after some vaccines. Simple febrile seizures generally cause no lasting harm.
- The MMR-autism claim began with fraudulent, retracted research and has been refuted in very large studies since.
- Severely immune-compromised children need individual assessment, especially for live vaccines.
- Vaccination protects babies too young to be vaccinated and people who can't be.
- Delayed schedules don't reduce any known risk. They extend the window of vulnerability.
What to actually do#
MUST - HighVaccinate on the current recommended schedule unless a clinician identifies a real contraindication
Large, consistent evidence of benefit; very rare harms
MUST - HighGet immediate help for signs of a severe allergic reaction after vaccination
Rare and treatable — but treatable only if treated. Clinics are prepared for this
RECOMMENDED - HighTell the clinician about immune compromise, prior serious reactions, allergies, and relevant medications before vaccinating
These are the situations where individual assessment genuinely changes the plan. Population evidence can't settle a specific case
SKIP - HighSkip alternative or spread-out schedules offered as a safety measure
No demonstrated safety benefit, and a real cost: longer unprotected
SKIP - HighReject the vaccines-cause-autism claim
Fraudulent origin, retracted paper, and multiple very large studies finding nothing
AVOID - HighDon't reason "these diseases are rare now, so we can stop"
They're rare because of vaccination. This is the argument that unwinds itself
The concerns, one by one#
| Concern | Why it fails |
|---|---|
| Autism | The originating study was fraudulent and has been retracted. Since then, enormous studies have looked for the link and not found it — including a Danish study of more than 500,000 children. This is one of the most thoroughly investigated non-associations in medicine |
| Too many vaccines at once overwhelms the immune system | No evidence supports this. A child's immune system handles vastly more antigens in ordinary daily life than the schedule contains |
| Allergic reaction | Possible, extremely rare, and treatable. This is why you wait in the clinic afterwards |
| Fever and febrile seizures | A small temporary risk after some vaccines. Frightening to watch; simple febrile seizures are not associated with lasting damage |
| Delaying is safer | There's no risk that delaying reduces. There is a cost it creates: more months unprotected, during the period when many of these diseases are most dangerous |
| These diseases are mild anyway | Even mostly-mild diseases produce severe cases at scale. Measles before widespread vaccination: 3–4 million US cases and around 500 deaths per year. Those deaths weren't from an unusually severe disease; they were from a common one meeting a large population |
Why other people's choices matter here#
Vaccination is one of the few parenting decisions with an effect outside your household. Newborns too young for certain vaccines, children in cancer treatment, and people with immune conditions rely on the people around them being vaccinated.
This is worth naming explicitly because the rest of the book is legitimately about optimizing for your family. This chapter is the exception, and it's the exception for a structural reason rather than a moral one: the benefit is partly collective.
Numbers in context#
| Number | What it means |
|---|---|
| Measles pre-vaccine: 3–4 million cases, ~500 deaths per year in the US | The baseline that "these diseases are harmless" has to argue against |
| Danish MMR study: 500,000+ children | Large enough that a meaningful autism effect could not have hidden in it |
| Serious adverse reactions: extremely rare | So rare that precisely quantifying them is itself difficult — which cuts against alarm, not toward it |
Important
Vaccine products, schedules, and contraindications change. Confirm timing and post-vaccine care with your child's clinician rather than the book's 2019 schedule.
Practical playbook#
- Get the current schedule at the first pediatric visit and put future doses in the calendar. Missed appointments are the most common real-world failure mode
- Tell the clinician about serious allergies, immune compromise, previous reactions, and medications
- Ask what short-term reactions to expect and which symptoms warrant a call. Knowing that a fever is expected prevents a panicked night
- Keep the vaccine record somewhere you can find it — school, travel, and new clinicians all need it
- If a dose is late, use the catch-up schedule. A delayed series is not a failed one, and there's no reason to abandon it
Where the evidence runs out#
- Extremely rare events are hard to measure precisely even in very large datasets.
- Protection wanes for some vaccines, and booster recommendations evolve.
- Individual contraindications need clinical judgment. Population evidence can't resolve every special case, which is exactly why the conversation with your clinician matters.
Our family's notes#
- Clinician's current schedule:
- Known contraindications or allergy questions to raise:
- Next doses and dates:
- Expected reactions and the threshold for calling:
- Where the record lives: