By Sunetra Gupta
Unherd, October 17, 2020: Yesterday in parliament, Matt Hancock explained to the house why, “on the substance”, the central claim of the Great Barrington Declaration was “emphatically not true”.“Many diseases never reach herd immunity – including measles, malaria, AIDS and flu…” he said. “Herd immunity is a flawed goal – even if we could get to it, which we can’t.”
Let’s have a look at the diseases he mentions. Measles, if it arrives on ‘virgin soil’, can devastate a population. In Tahiti and Moorea and the South-east and North-west Marquesas, between 20% and 70% of the population was lost to the first epidemic. Natural infection with measles provides lifelong immunity, and we now have a vaccine which provides similar solid, durable protection. We have not been able to eliminate the disease, but those who rather selfishly choose not to vaccinate their children are only able make that choice because the risks of infection are kept low by those who are immune — currently, a combination of those, like me, who caught it and recovered and many others for whom it is vaccine induced. The vaccine does not work in babies, which is why you have to wait till they are a year old before they get it. We can do this because herd immunity keeps the risk of infection down, so they are are unlikely to be infected in their first year of life. Without this herd protection, many under ones would die (as they regularly do in sub-Saharan Africa) despite a vaccine being available.
