A report came out recently suggesting that there is a large variability in the levels of antibodies to COVID-19 and that they tend to disappear in a matter of days and weeks. This has been reported in this preprint and that preprint so it has not gone through all checks. But it agrees with some other evidence, discussed here, that patients can indeed get the virus twice. There are now more studies pointing in that direction, and indeed, the similarity of SARS-CoV-2 virus to other coronaviruses would suggest that the immunity might not be long-lasting.
If this is true, it has some very serious consequences. It would mean that the whole idea of “herd immunity” is not valid in the long run. It would mean a collapse of the Swedish strategy which also – despite all contradictions – appears to be the British way of dealing with the virus. If indeed SARS-CoV-2 is more similar to a common cold than to flu, we do indeed need to learn to live with the virus for a long time.
On the positive side, a serology study which looked at both exposed and unexposed individuals found a large variety of immunological responses. If I understand this study correctly (and I am not an expert in immunology), many individuals who have never been exposed to SARS-CoV-2 are showing an immunological response. In fact, they claim 81% do.
Again, if this is true, it suggests three things. Firstly, the tests are likely to show a lot of false positives. In other words, if somebody is tested and gets a positive result, it does not mean this person was exposed to SARS-CoV-2.
Secondly, and related to my point about the short-lasting immunity, even if a person was indeed infected, there is no guarantee they are immune. Thus, any idea of “immunity passports” is irrelevant.
But thirdly, perhaps there is actually a high – although not as high as 80% – the general level of resistance to the virus. Perhaps the epidemic will indeed slow down soon and the virus will become a nuisance (like a common cold) rather than a deadly enemy.
In the light of these findings, I marvel about the complexity of creation – and about the peculiar beauty of viruses and the ways our bodies deal with them.
But also a word of warning. As I said in my article in The Conversation about the herd immunity, politicians often get fixated onto simple concepts – like “herd immunity” – which are in fact not simple at all.