Antibodies could determine fourth vaccine eligibility - study

The level of antibodies in a person's blood could be the most effective way to determine if they need a fourth Covid-19 vaccine, and if so when they should get it, new research has indicated.

Director of the UCD Centre for Experimental Pathogen Host Research (CEPHR) Professor Paddy Mallon said the university is part of a European Commission- funded consortium called Vaccelerate.

The consortium has brought scientists and clinicians from around Europe to explore questions around the fourth dose of the vaccine.

Speaking on RTÉ's This Week, he said: "We're actually leading a study called Boostavac, which is a clinical trial in adults over the age of 18 to try and explore what's the ideal timing for a fourth dose vaccine and that trial is just started recruiting in Ireland." He added: "Specifically for the Boostavac trial we're looking for people who've had three doses of the Pfizer vaccine, because the trial involves a fourth dose of the Pfizer vaccine." He said it is hoped to have it in operation in more than 20 sites across Europe to study when is it appropriate to get a fourth dose and what is the right timing between the third and fourth dose of the vaccine. Latest coronavirus stories Prof Mallon said it is based on data which suggests that the "level of antibodies that you have in your blood, whether induced by vaccination or just by infection, there may be a specific level that offers you sufficient protection and maybe the best thing to do is when your antibody level drops below that threshold, that's the ideal time for a booster vaccine." He said UCD has developed an antibody test. "It's a blood test, and you actually get what's called a quantitative antibody, so you get a level that tells you how much antibodies