Measles infecting brain cell
Measles infection in a brain cell nucleus

Having gone through Parts I, II, III, and IV of Measles week, let’s finish up by asking what this means for measles vaccine.

We know that measles death rates dropped spectacularly well before the vaccine was introduced in 1963 (the first version; a more effective version was released later). We know, too, that this reduction in deaths was solely because of case-fatality rates — measles was just as common in 1955 as it was in 1910, almost every child got it, the difference was that in 1950 fewer than 1 in a thousand cases died, whereas in 1910 somewhere between 1% and 30% of the cases1 died — over a hundred times higher.

Measles deaths (and case-fatality rates) more or less plateaued in the 1950s.  After vaccination was introduced, measles cases dropped by maybe 90% (see the chart below), and measles deaths dropped along with the case number.

Measles week
Part I: Introduction
Part II: Emerging disease
Part III: Not the answers
Part IV: Some of the answers
Part V: What about the vaccine?
References

First question– would deaths have continued to plummet if there was was no vaccine? I’ve seen people trying to extrapolate the drop outward with a simple trendline, but that doesn’t make sense — it assumes that it’s a single, linear trend.  That’s clearly not the case. By 1953-ish, a decade before the vaccine was introduced, measles death rates had pretty much flattened out, both in England and in the USA. (Check out charts in Part I, and here.) Case-fatality rates in England hovered at just about 0.02% from 1953 on. (They plateaued at a slightly higher rate in the US, about 0.09%.)

One in ten

In fact, we see very similar case-fatality rates in modern-day measles epidemics in the first world, as in the 1950s:

  • In England, measles cases over the past 30 years have had a just a tick more than 0.02% case-fatality rates.
  • In Switzerland from 2006-2009, 1 death in 4000 cases, 0.025%;2
  • The numbers are confusing in the Italian outbreak of 2002-2003, with different death numbers and estimated cases being offered in different papers,3 and with no clear case number of diagnosed measles.  (“Although notification is statutory, measles cases are often not reported.4 ) Hard numbers give a death rate of 0.2% (ten times higher than the 1950s), but that’s based on a clearly-incomplete case number; soft numbers — estimated cases, which are not comparable to the other stories here — give lower case-fatality rates.
  • European cases in 2006-2007, a 0.05% death rate in a few thousand cases — a little worse than England in the 1950s.5

So in the industrialized world, measles death rates are just about as low as we can get; without the vaccine, the  numbers of deaths wouldn’t have dropped any further after 1955 or so.

But secondly, death isn’t the only problem associated with measles. The estimated complication rate in Italy (2002-2003) and in Switzerland (2006-2009) was about 10% of cases, and this is very typical of measles today.:

It is well known that measles infection can cause serious complications and between 1.4% and 19.0% of measles cases that occur in industrialized countries require hospitalization … 6

Even if you don’t die, the disease is not trivial.

A large number of pneumonia and encephalitis cases were identified. The latter should be underscored, since long term sequelae of measles encephalitis are reported to occur in 20–30% of cases; this implies that between 28 to 41 of the 138 encephalitis cases may have subsequently developed permanent disabilities. 7

Measles cases & deaths in the US around vaccination
Vaccination & measles in the US: Case and deaths (inset) of measles before and after vaccination

Before vaccination, there were roughly 300,000 – 400,000 cases of measles per year in England; vaccination reduced the case number by about 90%. (See the chart of US measles numbers to the left – click for a larger version. I don’t think I need to show where the vaccine was introduced.)  Without even adjusting for the increase in population since then, and using the modern, industrialized-nation data for various complications and deaths, we can see that without vaccination for measles England8 would be seeing (at least) an extra:

  • 75 deaths per year (mainly in infants)
  • 500 cases of encephalitis
  • 10,000 cases of pneumonia
  • 50,000 hospitalizations
  Vaccinating the poor / Drawn by Sol Ettinge, Jun. 1872
Vaccinating the poor. By Sol Ettinge, Jr.
Harper’s Weekly, March 16, 1872

One other interesting thing about measles and measles vaccine.  A couple of years ago, talking about smallpox eradication, I summarized some of the reasons that it was possible to eradicate smallpox as a natural disease. Smallpox:

  • Has no animal host. If you can eradicate the disease in humans, it won’t re-emerge from a mouse, or monkey, or bat reservoir — compare to yellow fever, for example.
  • Has no persistent phase. Smallpox either kills people, or they recover completely and eliminate the virus. In either case, if there are no clinical cases over a reasonable period, then you can be confident that there is no more virus.
  • Induces long-term immunity in survivors.
  • Was a fearful enough disease that the political will to eradicate it lasted through the campaign. Smallpox vaccination continued throughout civil wars and other upheavals.
  • Has a highly effective vaccine that confers long-lasting immunity.

Aside from the political will, all these things are also true for measles.  Technically, measles could be eradicated as effectively as was smallpox, and the World Health Organization has considered setting eradication as a goal.  But without the political will, it’s not going to happen; instead of eradication, the WHO is working toward “sustainable measles mortality reduction” (the WHO document [PDF forumat] is here).


  1. Yes, a huge range, just as is seen in third-world measles epidemics today[]
  2. Richard JL, Masserey Spicher V (2009) Large measles epidemic in Switzerland from 2006 to 2009: consequences for the elimination of measles in Europe. Euro Surveill 14[]
  3. Ciofi Degli Atti ML, Filia A, Massari M, Pizzuti R, Nicoletti L, D’Argenzio A , de Campora E, Marchi A, Lombardo A, Salmaso S (2006) Assessment of measles incidence, measles-related complications and hospitalisations during an outbreak in a southern Italian region. Vaccine 24:1332–1338.
    Filia, A., Brenna, A., Pana, A., Cavallaro, G. M., Massari, M., and Ciofi degli Atti, M. L. (2007). Health burden and economic impact of measles-related hospitalizations in Italy in 2002-2003. BMC Public Health 7, 169.[]
  4. Ciofi Degli Atti ML, Filia A, Massari M, Pizzuti R, Nicoletti L, D’Argenzio A, de Campora E, Marchi A, Lombardo A, Salmaso S (2006) Assessment of measles incidence, measles-related complications and hospitalisations during an outbreak in a southern Italian region. Vaccine 24:1332–1338.[]
  5. MUSCAT, M., BANG, H., WOHLFAHRT, J., GLISMANN, S., & MOLBAK, K. (2009). Measles in Europe: an epidemiological assessment The Lancet, 373 (9661), 383-389 DOI: 10.1016/S0140-6736(08)61849-8[]
  6. Filia, A., Brenna, A., Panà, A., Maggio Cavallaro, G., Massari, M., & Ciofi degli Atti, M. (2007). Health burden and economic impact of measles-related hospitalizations in Italy in 2002–2003 BMC Public Health, 7 (1) DOI: 10.1186/1471-2458-7-169[]
  7. Filia, A., Brenna, A., Panà, A., Maggio Cavallaro, G., Massari, M., & Ciofi degli Atti, M. (2007). Health burden and economic impact of measles-related hospitalizations in Italy in 2002–2003 BMC Public Health, 7 (1) DOI: 10.1186/1471-2458-7-169[]
  8. I have the English data at hand, which is why I’m using it rather than the US numbers[]