Measles is (literally) a deadly-serious disease. The recent outbreak in Zimbabwe is just one example of the dangers of this vaccine-preventable disease.
First, some anecdata:
A MEASLES outbreak continues to wreak havoc in Nyazura’s Nzvimbe area, killing at least 30 people, mostly vulnerable children and women members of Johanne Marange Apostolic Church, who are entrenching their resistance to vital life-saving interventions. [http://www.zimgossip.com/?p=1080]
CHILDREN are dying of measles in a remote part of eastern Zimbabwe, where a religious sect insists on using only holy water to treat the contagious disease. [...]
The families are members of the Johanne Marange Apostolic Church. The church’s leaders do not allow vaccination or allow followers to seek medical treatment. [http://news.scotsman.com/world/Measles-kills-children-of-antivaccination.5929748.jp]
Italy, 2002: 4 deaths, 594 hospitalizations.
California, 1989/90: 75 deaths, 3,390 hospital admissions.
Japan, 2000: 88 deaths.
Germany, 2006: 160 children hospitalized, 3 with brain inflammation.
Ireland, 2000: 3 children dead, 350 hospitalized. [http://layscience.net/node/198]
In the case of the Duisburg outbreak in Germany, measles had a high mortality rate of 1 in 307 as two of the three young people with encephalitis died. The two children who developed encephalitis and died were aged 2 months, and 2 years. The infant was too young for vaccination and would have relied upon herd immunity for protection. [PDF]
Coverage, Incidence, and Deaths
I’ve been looking at the WHO figures for vaccine coverage against measles in the UK and incidence of measles. I also looked again at the HPA figures for incidence and deaths.
First, the WHO data:
In the eight years of the 1980s for which data is available, protection against measles from a vaccine ran from 52% (in 1981) to 84% (1989), and 1989 was the only year in the 80s that saw a figure above 80% – the mean average for vaccine coverage was 66.75%.
The notifications of measles in the 1980s ran from 30,160 in 1989, when coverage was 84%, to 114,948 in 1983 (coverage had not reached 60% in that or the previous two years). The mean average incidence of measles for these eight years was 75,483.
In the nine years for which data is available for the 1990s, coverage was 89-92%. The mean average for vaccine coverage was 91.22%.
The notifications of measles in the 1990s ran from a low of 74 in 1998 to a high of 28,228 in 1990 (1991 was the year in which coverage first reached 90%). The mean average incidence of measles for these nine years was 12,068.
The difference between the 1980s and 1990s in terms of incidence of measles is notable – there were more than six times as many notifications of measles in the 1980s than the 1990s. As vaccine coverage rose, the number of cases of measles plummeted.
In terms of the seriousness of the disease, it is expected that one in one hundred cases of measles leads to hospitalisation – that would mean we would expect to see around 6,000 people hospitalised during the 1980s when coverage was below 90% and around 1,000 during the 1990s when coverage averaged just over 90%.
We would also expect to see meningitis / encephalitis in one in one thousand cases – equating to roughly 600 people in the 1980s and roughly 100 in the 1990s. That’s quite a difference.
As for deaths – the figures in the “MMR the Facts” PDF suggest a death rate of 1 in 2,500 to 1 in 5,000. This would equate to around 20-40 deaths in the 1990s and around 120-240 deaths in the 1980s.
The figures from the HPA give us a total of 15 deaths in the 1990s and 89 deaths in the 1980s. This is slightly less than the figures I projected using the estimate from the MMR The Facts leaflet, but the ratio is still the same – six times as many people died from measles in the 1980s than in the 1990s.
This should not be a surprise, given that six times as many people contracted measles during the 1980s as compared with the 1990s – but it does help to illustrate (1) why vaccine coverage needs to be around 90% and (2) that measles is no less deadly now than it was in the 1980s when 90 people in this country died from the disease.
In a decade when vaccine coverage is too low:
- Tens of thousands more people will contract measles and become ill.
- Thousands more people will be ill enough to be hospitalised.
- Dozens more people will die.