Covid-19 infection and immunity

[Ellener]

https://blogs.sciencemag.org/pipeline/archives/2020/05/15/good-news-on-the-human-immune-response-to-the-coronavirus I looked this up after a friend just told me infection doesn't give immunity, I thought she was wrong so I read the study mentioned in the link, posted the link because it explains all the medical terms; this was their conclusion:

In sum, we measured SARS-CoV-2-specific CD4+ and CD8+ T cells responses in COVID-19 cases. Using multiple experimental approaches, SARS-CoV-2-specific CD4+ T cell and antibody responses were observed in all COVID-19 cases, and CD8+ T cell responses were observed in most. Importantly, pre-existing SARS-CoV-2-cross-reactive T cell responses were observed in healthy donors, indicating some potential for pre-existing immunity in the human population. ORF mapping of T cell specificities revealed valuable targets for incorporation in candidate vaccine development and revealed distinct specificity patterns between COVID-19 cases and unexposed healthy controls.

This is Derek Lowe's response to the study:

 

And here’s something to think about: in the unexposed patients, 40 to 60% had CD4+ cells that already respond to the new coronavirus. This doesn’t mean that people have already been exposed to it per se, of course – immune crossreactivity is very much a thing, and it would appear that many people have already raised a response to other antigens that could be partially protective against this new virus. What antigens those are, how protective this response is, and whether it helps to account for the different severity of the disease in various patients (and populations) are important questions that a lot of effort will be spent answering. As the paper notes, such cross-reactivity seems to have been a big factor in making the H1N1 flu epidemic less severe than had been initially feared – the population already had more of an immunological head start than thought.

So overall, this paper makes the prospects for a vaccine look good: there is indeed a robust response by the adaptive immune system, to several coronavirus proteins. And vaccine developers will want to think about adding in some of the other antigens mentioned in this paper, in addition to the Spike antigens that have been the focus thus far. It seems fair to say, though, that the first wave of vaccines will likely be Spike-o-centric, and later vaccines might have these other antigens included in the mix. But it also seems that Spike-protein-targeted vaccines should be pretty effective, so that’s good. The other good news is that this team looked for the signs of an antibody-dependent-enhancement response, which would be bad news, and did not find evidence of it in the recovering patients (I didn’t go into these details, but wanted to mention that finding, which is quite reassuring). And it also looks like the prospects for (reasonably) lasting immunity after infection (or after vaccination) are good. This, from what I can see, is just the sort of response that you’d want to see for that to be the case. Clinical data will be the real decider on that, but there’s no reason so far to think that a person won’t have such immunity if they fit this profile.

Onward from here, then – there will be more studies like this coming, but this is a good, solid look into the human immunology of this outbreak. And so far, so good.

Interesting my friend is from Arkansas and so is Dr Lowe! Glad she was wrong 🙂 

This is his follow up piece https://blogs.sciencemag.org/pipeline/archives/2020/05/21/there-may-be-a-unique-coronavirus-immune-response but I've read enough medical jargon for one day!