Weighing the Evidence

How a Vaccine Teaches the Body

Your immune system learns. Meet a disease once and, if you survive it, you are usually protected afterwards. A vaccine gives the lesson without the disease. The method is old. In eighteenth-century Britain, milkmaids were known not to catch smallpox. Edward Jenner reasoned that the cowpox they caught from cattle was protecting them, and in 1796 he tested it on a boy — a procedure no ethics committee would permit now. A modern vaccine shows the immune system a harmless piece of a pathogen: a killed virus, a weakened one, or a single protein from its surface. The body makes antibodies against that piece, and keeps the recipe. Because the recipe is kept, the real pathogen is met by a defence already in place. There is a second effect. If enough people are immune, the pathogen cannot find a chain of hosts, so those who cannot be vaccinated are protected too. That effect fails below a threshold, which is why coverage rather than availability is what matters.

What Happened to the Textile Towns

Between 1965 and 1990 the British textile industry lost roughly four fifths of its jobs. Three causes are usually given, and they are not equally weighted. Cost is the one most often cited. Spinning and weaving are labour-intensive, and wages in the countries that took the work were a fraction of British wages. This explains a great deal. Investment matters too. Much British machinery dated from before the war. Where firms did re-equip — and some did — they survived longer, which suggests the cost argument is not the whole story. The third cause is the hardest to see: the industry was concentrated. A car plant closing takes a town's largest employer; a mill closing often took its only one, along with the suppliers and the shops that depended on it. That concentration is why the closures show up in the population figures of particular towns and not in national ones.