So why do boosters help so significantly compared with first and second jabs, and are we on a conveyor belt towards needing an ever-increasing number of top-ups? Even before Omicron, it was clear boosters would be required to maintain the levels of protection against infection, although protection against severe illness appeared to be holding up well. Vaccines prompt the body to make neutralising antibodies that intercept Covid before the virus infects our cells, but circulating antibodies can wane over time. Data from Israel, one of the first countries to vaccinate its population, showed a drop-off in protection against infection after only three months. The next generation of vaccines, scientists hope, will not only be a good match to circulating strains but provide far broader immune protection so that they are effective against mutations.

Source: The Guardian December 13, 2021 07:00 UTC