redsturgeon wrote:Arizona11 wrote:If the body has reasonable immunity after having a jab, why are they giving out boosters? Presumably because they give even better protection.
My wife is under 65 but would like the booster. As so many over 65s will not bother to get the booster, could they not give it instead to younger people who would like it?
The evidence shows that the booster will not prevent you from catching the virus, nor stop you passing it on to anyone else. ...
Are you sure that's true John? I suppose that "preventing you from catching the virus" could be taken to mean 100% efficacy in which case yes, none of the vaccines are ever 100% effective at preventing infection, but I thought that at least in the first couple of months after a booster antibody levels went back to very high levels such that, even with some quite significant reduction in neutralising capability against newer strains than the booster was designed for, the level of cross neutralisation was still high enough when taken together with the temporary very high levels of antibodies to still give some protection against infection (50% or so efficacy or maybe slightly higher?).
Maybe the government thinking here, presumably informed by the epidemiologists they are consulting, is that even if the boosters only offer a 50% reduction in risk of infection for 2 or 3 months after administration that might still be useful in keeping case rates down and giving fewer opportunities for additional mutations to occur.
Also, you do go on to mention that the vaccines have a significantly more durable effect re preventing severe disease but for some people who only ever had their first booster that might have been coming up to 2 years ago now and my understanding is that while protection against severe disease is more durable it does still show at least some modest decline over time so maybe the government policy makers are exercising some caution there and, for the more vulnerable, wanting to ensure that protection against serious illness gets bumped up again where possible rather than staying on a course of even very gradual year-on-year decline.
Re the short-term boost in antibody levels, here's some recent Moderna results on its latest vaccine - an 8.7 fold increase in neutralising antibodies at least initially - https://www.cnbc.com/2023/09/06/moderna ... riant.html
Yes, it would be no surprise to see those antibody levels contract quite significantly after a few months but maybe the epidemiologists do think that even 2 or 3 months of attenuated transmission might have a significant impact on the size of the peak of the next wave, particularly among the elderly and vulnerable demographic, and that an extra boost over even still pretty decent existing protection against severe illness can't do any harm in terms of reducing the strain on the NHS over this next winter season (and with the possibility of the NHS still having to deal with strike action on top of everything else this next winter season must be looking pretty scary to government planners right now so I can understand an "every little helps" mentality right now).
- Julian