Thread by @AdamJKucharski

How long does immunity to SARS-CoV-2 last (and how long might it last in future)? A few thoughts... 1/

We now have data from several cohort studies showing responses can last over a period of several months at least. E.g. "Based on data currently available, a rapid decline of SARS-CoV-2 IgG seropositivity or neutralising capacity has not been seen." thelancet.com/journals/lanin… 2/

And "immune memory in three immunological compartments remained measurable in greater than 90% of subjects for more than 5 months after infection" science.sciencemag.org/content/371/65… 3/

And "A previous history of SARS-CoV-2 infection was associated with an 84% lower risk of infection, with median protective effect observed 7 months following primary infection." thelancet.com/journals/lance… 4/

One of the issues with interpreting apparent 'waning' in studies last year was cutoffs for a 'positive' test were often based on more severe cases, which means they were less good at assessing antibody dynamics following milder infections: medrxiv.org/content/10.110… 5/

In discussion of 'waning', also need to remember (given what we know about flu & other coronaviruses) that immunity against similar viruses may be long-lasting, but evolution leads to variants against which immunity is less effective:

https://twitter.com/jbloom_lab/status/1385664873749639168?s=20

6/

In summary, we have promising data on persistence of post-infection immunity, which bodes well for COVID vaccines against they viruses they were designed for. For me the biggest concern is potential for evolution, which may well necessitate future vaccine updates... 7/

But let's be careful to not undermine the very useful tools we have while we talk about the possibility of future challenges. 8/8