Bloomberg. “When we were celebrating the amazing effectiveness of booster shots against the delta variant, the bar was already being raised by omicron." “It seems like we are constantly trying to catch up with the virus," she said.
Several studies have also shown that the effect of vaccines diminishes with time. Previously an article published in Nature magazine suggested that people immunized against COVID-19 would lose approximately half of their defensive antibodies every 108 days or so.
As a result, vaccines that initially offered, say, 90% protection against mild cases of disease might only be 70% effective after 6 or 7 months. ‘Neutralizing’ antibodies that can intercept viruses before they infiltrate cells might not have much staying power.
Levels of these molecules typically shoot up after vaccination, then quickly taper off months later. “That’s how vaccines work," said Nicole Doria-Rose, an immunologist at the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, as quoted by Nature Owing to these factors, the WHO had suggested the current COVID-19 vaccines may need to be reworked to ensure they are effective against future variants. "The composition of current COVID vaccines may need to be updated to ensure that vaccines continue to provide WHO-recommended levels of protection against infection and disease by VOCs, including Omicron and future variants," they said.