Herd immunity for Covid-19 is a tantalising possibility, but it’s far from certain whether we can achieve it. With the right vaccines, it will be possible, but there is still much that is uncertain.
For more information about herd immunity – what it is and how it works – there’s a great overview from the Oxford Vaccine Group.
For a discussion of the challenges facing us in achieving herd immunity, I’ve got two suggestions. There’s the article here, from The Atlantic, which gives a good overview. For more detail, there’s an article in The Lancet, which includes the equations for determining the proportion of people who need to be vaccinated to reach the threshold for herd immunity.
One aspect of herd immunity that I didn’t cover in much detail was the question of whether vaccines prevent transmission of a virus, or just protect people from becoming sick. This article from the BBC explains the issues and talks about a number of different vaccines, as well as what we know about the vaccines for Covid-19.
Finally, here’s an article from a fellow Substack writer on the same topic. He gives a more in-depth look at the data, especially on the Oxford-AstraZeneca vaccine, and what that means for herd immunity. It’s not at all encouraging, unfortunately. One of the important conclusions is that infection control measures, such as maintaining physical distance, hygiene and a rigorous system for testing, isolating and contact tracing, will remain important for some time to come. It’s a reminder to all of us, right now, so keep up the good work!
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