There’s no evidence that any of the current Covid-19 vaccines can completely stop people from being infected – and this has implications for our prospects of achieving herd immunity.
It was 17 June 2009. An 11-year-old boy returned to the US from the UK – and inadvertently brought something with him. Later that week, while attending a religious education programme in Sullivan County, New York, he developed a mysterious swelling of his salivary glands. He had mumps, a respiratory infection spread by contact with droplets in the air.
Meanwhile, the religious course continued. The 400 children in attendance spent hours each day engaging in prolonged face-to-face contact – specifically, a kind of Orthodox Jewish education involving facing a study partner, a chavrusa, across a narrow table, while analysing and debating text from the Talmud. By the time the programme ended, 22 others had been infected, along with three adults.