A preprint published in medRxiv August 15th 2021, by Gilbert and others reviewed this issue.
In the Coronavirus efficacy trial, they found the mRNA-1273 vaccine, the Moderna vaccine was 94% efficacious against COVID-19 disease. SARS-CoV-2 antibody measurements were assessed as correlates of COVID-19 risk and as of correlates protection.
Participants were selected for measurement of four serum antibody markers at day 1 the first dose, day 29 the second dose, and day 57. IgG binding antibodies to the spike, B antibodies to spike receptor-binding domain RBD, and 50% and 80% inhibitory dilution pseudovirus neutralising antibody titres calibrated to the WHO standard were measured. Participants with no evidence of previous SARS-CoV-2 infection were included.
After receiving the vaccine people with relatively low levels of antibodies were more likely to develop symptomatic infections than were those who mounted a stronger antibody response – according to analysis of such breakthrough infections during the vaccines’ efficacy trial.
This adds to the growing evidence that neutralising antibodies, which can block viral infection of cells, are a marker of vulnerability to COVID-19.
The team compared levels of these antibodies in the nearly 50 vaccinated trial participants who developed breakthrough infections with levels in match controls who were not diagnosed with COVID-19.
The research authors found that people with undetected levels of neutralising antibodies were 10 times more likely to develop COVID-19 than individuals whose antibody levels placed them in 90th centile of all study participants.
LGP, The London General Practice, the leading London Doctors’ clinic in Harley Street commends the Government on its vaccination programme and encourages all those eligible to be vaccinated.
It also looks forward to the Government deciding that all patients should receive booster vaccines.
Dr Paul Ettlinger
Founder, The London General Practice