NHS vs CDC, why are the adult vaccination recs so different?
May 9, 2024 10:02 AM   Subscribe

The CDC recommends adults have a tetanus booster every 10 years. The NHS doesn't think adults need a tetanus booster if they were fully vaccinated as kids. As an oldish person working on a farm at high risk of small dirty wounds, I got the NHS to give me a tetanus booster 10 years ago but they seemed bemused that I wanted it. Do any medical MeFites know why the recommendations are so different?
posted by Rhedyn to Health & Fitness (15 answers total) 5 users marked this as a favorite
There were only 4 cases of tetanus in England in 2022, and 0 deaths. Even allowing for under-reporting, that level of prevalence doesn't seem to justify public health interventions (or public spending) beyond the existing childhood vaccination.
posted by Klipspringer at 10:25 AM on May 9 [3 favorites]

Best answer: I can't speak to this specifically, but I do science (epidemiology) in a different field, and have learned a bit about differences between NHS recommendations and CDC recommendations. In the areas I work in, the differences are clearly driven by different philosophies about risk, and different concerns about cost.

On the philosophical point -- For the health issues I study, the NHS takes a harm reduction and collective approach, while the CDC takes a more individual approach. What this means is that the NHS tends to seek solutions that are optimal at the population level, while the CDC seeks solutions that are optimal for individuals. This distinction is by no means absolute, and I am NOT saying that the NHS doesn't consider individuals or that the CDC doesn't consider the population level. Health issues are very complex -- for example, vaccinating the whole population for COVID does more for individual health than vaccinating only those individuals who are worried about getting COVID. It's a matter of emphasis.

While I can't speak to the tetanus vaccine specifically, my first thought is to wonder about the impact of adult tetanus boosters at the population level -- does boosting adults improve overall health outcomes? or is it only a small, marginal benefit for specific populations? I have no idea, but it's something I would look into if I wanted to know more about this specific issue.

On the cost point -- The NHS pays for providing health care and for insurance. So they themselves bear the costs of their recommendations. I would assume that somewhere in the NHS, there has been a calculation of the costs of boosting adults for tetanus versus the benefit of reducing tetanus-related disease and death, and that people who decide things decided that the value of adult boosters was less than the cost.

By comparison, the CDC does not pay for providing health care and it doesn't provide insurance. In the US, Social Security, CMS, DOD and the VA are the big Federal insurers -- and the government itself as an employer -- with DOD and VA being the largest federal service providers. So while the CDC does consider cost when making recommendations, it is a bit more abstract for CDC than for NHS. Also, the ways that CDC recommendations factor into service provision and insurance coverage decisions by the rest of the Federal government is extremely complex.

TLDR (on preview); What Klipspringer said.
posted by OrangeDisk at 10:33 AM on May 9 [31 favorites]

Best answer: Boy, did you ever just send me down a rabbit hole! This is probably the definitive document from the WHO that contains the information you seek: The Immunological Basis for Immunization Series Module 3: Tetanus. Page 19 talks about the differences between US and UK recommendations for boosters for adults specifically.

But for the tl;dr, as with a lot of older treatments (tetanus vaccines have existed since the 1930s) there has never been a randomized controlled clinical trial of tetanus vaccine. There's good evidence that if you get a dose as a teen it will last you well into adulthood, and in most people boosters probably protect for more like 20-30 years rather than 10 years. There are some historical reasons surrounding the original decision to do every-10-years boosters in the US (concerns about the potency of the original vaccine, basically) that no longer apply.

Once something becomes the "standard of care," though, it generally requires a lot of evidence to induce a switch to something else. So in the US I'm guessing the rationale is basically that we've been giving these every ten years for almost a century and TT vaccines are generally well-tolerated (don't have a lot of dangerous side effects) and inexpensive so there's no particular reason not to *keep* giving them every 10 years.

On the other hand, if, as in the UK, you *never* offered 10-year boosters, there's no particular reason to start now.

Only 33 cases of tetanus and 2 deaths in the US in 2017, so the incidence is in the same ballpark as the UK numbers Klipspringer cites.
posted by mskyle at 10:35 AM on May 9 [11 favorites]

There are very few cases in the US too, around 30 per year.

The UK recommendations are here. The logic seems to be that there's no evidence that childhood vaccines wear off: "It will therefore be at least another 20 years before surveillance will determine whether those individuals who completed a 5-dose course routinely as children are still protected in later adult life."

The US recommendations from 2006 are here, and says "ACIP [Advisory Committee on Immunization Practices] has recommended that adults receive a booster dose of tetanus toxoid-containing vaccine every 10 years, or as indicated for wound care, to maintain protective levels of tetanus antitoxin." That document cites this 1990 recommendation, which observes that, "Available evidence indicates that complete primary vaccination with tetanus toxoid provides long-lasting protection greater than or equal to 10 years for most recipients."

This supports what mskyle said: The US thinks, hey, we don't have strong evidence they are still effective after 10 years, so let's give a booster. The UK thinks, hey, we don't have any evidence that they wear off, so why give a booster?
posted by Mr.Know-it-some at 10:41 AM on May 9 [2 favorites]

The NHS doesn't give tetanus boosters by default, as people above have said, but if you catch yourself on a rusty nail they will give you a tetanus shot as a precaution (or at least they did to me a few years ago, and I was fully vaccinated as a child).

So it's not that they won't give you a booster if there is good reason to have one, it's just that they don't give them prophylactically to the general population for the reasons explained above.
posted by underclocked at 11:09 AM on May 9 [2 favorites]

In the US it’s less about tetanus and more about the acellular pertussis part of the combined Tdap vaccine. The efficacy of the acellular pertussis vaccine wanes faster than the other components, and strong herd immunity is important for protecting babies, which are particularly susceptible to complications or death from pertussis and which can’t get vaccinated themselves until 2 months, and the full childhood series is 5 doses.
posted by jedicus at 12:40 PM on May 9 [12 favorites]

It's probably worth noting that most adults in the US get a Tdap booster, which covers tetanus, diphtheria, and pertussis (whooping cough). So looking strictly at tetanus number may be misleading. When my niece was about to be born, the OB recommended all adults in the family get the booster if not current to help protect her from whooping cough.
posted by advicepig at 12:45 PM on May 9 [3 favorites]

Right, like jedicus said while I was looking up spellings....
posted by advicepig at 12:46 PM on May 9

Best answer: There's also this press release from Oregon Health & Science University in 2016: Study shows tetanus shots needed every 30 years, not every 10.
posted by paduasoy at 12:53 PM on May 9 [6 favorites]

In comparison the Polish system is more similar to the NHS (free at point of care, though there's a different funding stream) and they recommend TDaP every ten years. There's a note that most tetanus cases happen to people above the age of 65, which indicates either waning immunity or those being cases before the Polish vaccination program really got to 100% of kids. Apparently even if you're vaccinated, only 25% of the population has a testable amount of antibodies at 65 if no boosters are given, while with boosters it's 75% when tested at 8 years from the last booster. Generally doctors don't chase up people about those shots, but they'll give you one if you had any wound that soil got into.

(Considering the high incidence of pertussis in Europe lately, I'm quite glad I'm up to date on my shots.)
posted by I claim sanctuary at 1:11 PM on May 9 [1 favorite]

My schedule here in Sweden is every 20 years (checked last week after I cut myself on rust again, dumpster diving electronics). ETA: I have since learned rust isn't the problem tho.
posted by Iteki at 1:18 PM on May 9 [2 favorites]

In Canada, where the government does pay for the vaccine, the recommendation is still every 10 years, but they say they are studying new evidence that a lower frequency might be acceptable. In practice, I think most people don't tend to bother and there's no formal system to remind people.

My sense is that these changes tend to happen very slowly in Canada and the US, while the UK tends to move a little bit faster (note here that contra the claim above, it seems the UK used to recommend 10-year boosters). There is a stronger focus on cost effectiveness of treatments in the UK system compared to Canada, even though the government pays for most treatments in both countries.
posted by ssg at 1:56 PM on May 9 [4 favorites]

I don't know that they take it into account, but aside from the £ cost of the vaccine itself, there's also the tangible and intangible costs associated with persuading people to have the vaccine. If it's on the schedule, they make an effort to get the relevant population to take it. But, unlike children (health visitors / schools), pregnant people (midwives), and older people (very likely to need to visit GP) for the general adult population you would need to do a mass promotion campaign, like the ones for cancer screening. Not only does this cost money, it also costs attention span - and it's clear from the evidence people have shared that tetanus vaccination would be very low down a list ranking by population or individual level health benefit.
posted by plonkee at 1:10 AM on May 10 [1 favorite]

For what it is worth, here in Australia, every doctor I've ever spoken to about it has told me to get a tetanus booster every 10 years.
posted by chariot pulled by cassowaries at 1:21 AM on May 10 [1 favorite]

To elaborate on the regulation in Australia, it’s recommended to consider a booster every 10 years, however funded by government only in the setting of an injury at risk of tetanus contamination (and the vaccine offered is aDT not DPT, no pertussis).

So the population health intervention ends up being: In clinical practice, what this means is that if you are looking after a wound that is high risk, you ask, “How long has it been since you had a tetanus booster?”, and if it’s been a long time, the vaccine can be administered at no cost to the patient.

However if you walk off the street and ask for a tetanus booster just cos, sure if it’s been 10 years but you have to pay for it.
posted by chiquitita at 7:58 AM on May 10 [1 favorite]

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