https://files.peakd.com/file/peakd-hive/zafrada/23ynmNFj9JixkkhZZMTRhZdwUzyCU2HqyxRC2Xu5Ly4oCFpjDZc1eGUrhLkELr874Lt5e.jpg



This is a laboratory study of the delta variant. The most interesting finding is that this variant spreads via the formation of syncytia, much more so than older variants.  Syncytia are giant cells made by fusing multiple regular cells together.  The first cell to be infected makes spike proteins on its surface, then the spikes fuse the infected cell with nearby cells, meaning that the virus has a larger cell in which to replicate.  

This strategy gets around the presence of neutralizing antibodies, because it doesn't require the infected cell to send out viruses to infect nearby cells.  If there are antibodies around, those antibodies would bind to the viruses in transit and block their ability to infect other cells.  

But on the other hand, syncytia make for a larger target for the immune system to kill, and it can kill a giant cell once and be done, whereas if you have a bunch of infected regular-size cells, you'd have to kill all of them individually. 

I think probably the biggest negative to syncytia formation is that it can damage a lot of cells (that are in contact with each other)  quickly.  So that gives the virus a head start to spread before the immune system has figured out what is going on.  

I'm sure that we will continue to get more information in the weeks to come about the behavior of this variant.  So far the vaccines seem to be holding up reasonably well against it, and when breakthrough infections are happening, they are usually mild.  So I don't think this variant is an unusually high threat to those who have immunity from vaccination.  It's not a bad idea to check your antibodies, though, as a small percentage of people are poor responders to the vaccine, and the delta variant is likely to continue to spread in the US in coming weeks. 

Link to the study : https://www.gov.uk/government/news/vaccines-highly-effective-against-b-1-617-2-variant-after-2-doses