دانلود کتاب ملت واکسن علم، خرد و تهدید ۲۰۰ سال پیشرفت

When Martha Lillard turned five, she had a birthday party at an amusement park. It was a crowded public place designed for having fun, but it was also where contagious infections may be rife. A week later she developed a fever and a sore throat, and soon after she began to get weak. Her parents suspected the worst because a deadly infectious disease was all around them. Their fears were confirmed when Martha was diagnosed with polio. She needed an iron lung to breathe and her entire body was placed inside the machine, with only her head free of the encasement. The virus had paralysed her diaphragm, the muscle essential for breathing, and the iron lung would need to breathe for her. The iron lung is a large metal contraption designed to create intermittent negative pressure to simulate breathing and take the place of the stricken diaphragm, helping the lungs expand and deflate. It was 1953, the peak of a polio epidemic in the United States, when hospital wards were full of people encased in iron lungs. As of 2021, Martha Lillard remained one of the very few people still kept alive by an iron lung. The machine looks like a small submarine, big enough to encase the whole body, with the head sticking out at the top. Imagine being imprisoned in a metal casing, being unable to walk or see the world. People have lived like that for up to 70 years. To make matters worse, spare parts for iron lungs are hard to come by these days, and power blackouts can be life-threatening. If there was a power blackout, family and neighbours had to help by manually pumping air into the iron lung using bellows. While the rest of us have forgotten the horrors of polio epidemics and images of hospital wards filled with iron lungs, parents at the time lived in fear of their child becoming paralysed, or worse, killed by polio. Up to this time, about 35 000 people a year in the United States were paralysed or disabled by polio. The introduction of polio vaccines in 1955 quickly turned this around, making polio extremely rare in the country and eliminated by 1994. There are now only two countries – Afghanistan and Pakistan – that still experience polio epidemics, and both are linked to low vaccination rates and opposition to vaccination. The first vaccine to be developed was against smallpox, a deadly disease documented in Egyptian mummies, which had plagued the world for over 3000 years. Until it was eradicated, one in three people with smallpox died, and in the 20th century alone there were somewhere between 300 and 500 million deaths from smallpox in the world. Smallpox was finally eradicated in 1980 thanks to effective smallpox vaccines and a determined, decade-long campaign for eradication from the World Health Organization (WHO). It appears that in ancient times and in multiple countries simultaneously, people realised that the technique of variolation, or introducing small quantities of the actual smallpox virus to a nonimmune person, could be protective. Usually, this involved lancing a pustule on the skin of an infected person and transferring the material from that pustule using a sharp instrument to someone else. This was called inoculation or variolation and could be quite dangerous because the person might develop full-blown smallpox. It could also result in the spread of other infections such as syphilis because of this unsterile method. An English aristocrat, Lady Mary Wortley Montagu, brought this technique to England after her travels in Turkey and catching smallpox herself in 1715. It turns out there are a range of similar viruses in the orthopoxvirus group of DNA viruses, and immunity against one can confer immunity against the others. Monkeypox, now called mpox, is also in the orthopoxvirus group. In 2022, when an unprecedented mpox epidemic swept the world, the vaccines used to control the epidemic were smallpox vaccines based on the cowpox virus.