Meningitis: where is the vaccine?

And so it began. The deadly strain of meningitis can be traced to a cluster of 16 unvaccinated schoolchildren in a small town in Germany. The fear is that if the large number of unvaccinated children were able to transmit the disease to others, others could die.

The kind of thing you think would happen only in Third World countries – or in places with open borders, which is to say, Mexico – it’s rare to see it in affluent states like California and New York, where in most cases vaccination rates are above 98 percent.

But there was and is a very real possibility of such an outbreak. The rates of unvaccinated children were unusually high in a small town in this largely Roman Catholic country, and the disease was spreading rapidly. There were 16 cases of Type B meningitis in the town – the types one and two are the most dangerous – and all of the infected children died. The death toll was so high in the town – 159 out of a population of 2,000 – that it was difficult to interpret the figures with a straight face.

There have been thousands of meningitis deaths in recent years, but some could be pinned on undiagnosed conditions, others might be linked to other forms of disease, and still others, like the recent outbreak in Argentina, might simply be one of those unfortunate clusters that scientists regard as natural and predictable. But even a small cluster of rare cases, in an area where vaccination rates are already pretty high, can have disastrous consequences.

Authorities in Germany, trying to assess the extent of the problem, launched a computer analysis of every case of Type B meningitis from 2000 to 2013.

The results weren’t encouraging. There were 588 potential cases out of the 10,635 people who were medically cleared to receive meningitis vaccine. But only 311 people had the vaccine. And of the 311, only 17 people actually got the vaccine.

This fact suggests that there are some people who are particularly vulnerable to meningitis, but they aren’t identified. It’s not often thought that people could miss the vaccine because they have a rare medical condition. It happens though, and it could happen here.

Of the vaccine-ineligible 280, 80 percent were foreign travelers, and the German government is worried that some of them might have brought the disease into the country.

This is very different from polio, a disease that, unlike measles, can spread widely, especially in places where there is limited vaccination. Many people with the rare and fatal Type B meningitis aren’t physically ill in the way that polio patients are, and aren’t symptoms in the way that polio patients are, either. But that doesn’t mean they don’t spread the disease. People living in close quarters may have bacteria on their hands or trays, for example, and the meningitis bacteria get mixed up and move around. As public health officials would say, the vaccines don’t just prevent the infection in those who are already sick with the disease, but also in those who might get sick.

In the region of New Guinea where the meningitis outbreak is now being documented, there were 56 total cases. Of those cases, 16 had received both doses of the meningitis vaccine. Still, more than 15 were unvaccinated. In Mexico, there were at least 180 deaths from meningitis since 2000, but there was some doubt as to whether many of those cases might have been caused by the disease itself or the little microbes that spread in outbreaks.

Babies are particularly vulnerable, and even in this more developed area of New Guinea there are concerns that some children weren’t vaccinated, although it appears that the mortality rate was relatively low at just two per cent.

One way of figuring out the vulnerability of a population to a dangerous disease is to isolate those at highest risk. In Guatemala, a study found that as many as 25 percent of people who go to the doctor were undiagnosed and about 10 percent were unvaccinated. But if you don’t count certain people at high risk, there is no way to tell who hasn’t been vaccinated, and what form of illness it is. So how does one know which populations are the most susceptible?

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