A landmark UK study from Imperial College London reveals that COVID-19 antibodies wane significantly within three months—dropping 26.5% on average—with sharper declines in those over 75 and asymptomatic individuals.
As the COVID-19 pandemic persists, understanding antibody dynamics is crucial for assessing herd immunity potential. Recent research has highlighted variations, such as 8.5% of infected individuals producing no detectable antibodies and children generating less diverse responses than adults. A key unanswered question: how long do these antibodies last? Imperial College London's REACT-2 program, detailed in an October 27, 2020, press release, provides vital insights. Researchers tracked 365,104 volunteers over three months from June to September 2020. Participants used self-tests for lateral flow assays (LFA) to detect IgG antibodies, with 17,576 testing positive.
Antibody prevalence fell from 6.0% at the program's start to 4.4% by its end, signaling a 26.5% average decrease over three months. This pattern held across all age groups, but was most pronounced in older adults: those over 75 saw a 39% drop, compared to just 15% in 18-24-year-olds, despite their initially weaker positives. Asymptomatic cases experienced an even steeper 64% decline, losing antibodies faster than symptomatic individuals.
"We don't yet know if this increases reinfection risk, but everyone must continue following protective measures," emphasized Helen Ward, a lead researcher.
Experts like Eleanor Riley, professor of immunology and infectious diseases at the University of Edinburgh, note limitations: the REACT-2 study measured antibody prevalence, not concentrations or functionality, and overlooked T-cell immunity. It's premature to conclude short-lived COVID-19 immunity. The findings don't imply vaccine failure, as vaccines include adjuvants that may elicit durable responses. A critical gap: how quickly would antibodies rebound upon re-exposure to SARS-CoV-2?
