The global debate around the need for vaccine booster shots against COVID-19 has heated up even further with a new analysis from Moderna on the effectiveness – and waning effectiveness – of its mRNA jab, mRNA-1273.
Ahead of the meeting of the Food and Drug Administration’s advisory committee in two weeks’ time, the new analysis “adds to evidence of potential benefit of a booster dose of mRNA-1273”, said Moderna.
The analysis – from the one-year follow-up of the phase 3 COVE study – shows that those vaccinated more recently had fewer breakthrough infections (88 cases) than those who received mRNA-1273 last year (162 cases). While the reduction in incidence rates was not significant, there is a “numerical trend”, said Moderna, adding that the analysis “quantifies the impact of waning immunity”.
The company also released new data from a real-world study following more than 350,000 recipients of the vaccine that showed high levels of immunity to the delta variant. mRNA-1273 had a vaccine effectiveness of 87% against COVID-19 diagnosis and 96% against COVID-19 hospitalization.
“It is promising to see clinical and real-world evidence adding to the growing body of data on the effectiveness of the Moderna COVID-19 vaccine,” said Moderna CEO, Stéphane Bancel. “The increased risk of breakthrough infections in COVE study participants who were vaccinated last year compared to more recently illustrates the impact of waning immunity and supports the need for a booster to maintain high levels of protection.”
He added that he hoped the findings would be “helpful” to health authorities and regulators as they “assess strategies for ending this pandemic”, a clear nod to the FDA’s soon-to-be-assembled advisory committee.
The politics of booster programmes has been highlighted in a paper published in the Lancet by a group of renowned international scientists, which reviewed all existing published data on COVID vaccine effectiveness.
“Although the idea of further reducing the number of COVID-19 cases by enhancing immunity in vaccinated people is appealing, any decision to do so should be evidence-based and consider the benefits and risks for individuals and society,” they wrote.
Their conclusion was that current evidence did not show a need for boosting in the general population, “in which efficacy against severe disease remains high”.
“Careful and public scrutiny of the evolving data will be needed to assure that decisions about boosting are informed by reliable science more than by politics,” added the scientists.
The focus for lead author, Dr Ana-Maria Henao-Restrepo, a veteran of the World Health Organisation’s Institute for Vaccine Research, is on poorer countries. “The limited supply of these vaccines will save the most lives if made available to people who are at appreciable risk of serious disease and have not yet received any vaccine,” she said.
“Even if some gain can ultimately be obtained from boosting, it will not outweigh the benefits of providing initial protection to the unvaccinated. If vaccines are deployed where they would do the most good, they could hasten the end of the pandemic by inhibiting further evolution of variants.”