antibodies decline

CHICAGO, Sept. 15 (Reuters) - New data from Moderna Inc's (MRNA.O) large COVID-19 vaccine trial shows that the protection it offers diminishes over time, supporting the case for booster doses, he said. the company in a press release Wednesday. .

"This is just an estimate, but we think this means that, looking into fall and winter, we at the very least expect the estimated impact of waning immunity to be an additional 600,000 COVID-19 cases," said Moderna's president. , Stephen Hoge, in a statement. conference call with investors.

Hoge did not project how many of the cases would be serious, but said some would require hospitalization.

The data is in contrast to data from several recent studies that suggested Moderna's vaccine protection lasts longer than a similar injection from Pfizer Inc (PFE.N) and German partner BioNTech SE.


Experts said the difference is likely due to Moderna's higher dose of messenger RNA (mRNA) and the slightly longer interval between the first and second injections.

Both vaccines proved extremely effective in preventing disease in their large Phase III studies.

However, Wednesday's analysis showed higher rates of infection among people vaccinated about 13 months ago compared to those vaccinated about eight months ago. The study period was from July to August, when Delta was the predominant strain. It has yet to undergo a peer review.

Moderna submitted her application to the US Food and Drug Administration on September 1 seeking authorization for a booster shot.

Hoge said the data from his booster studies show that the vaccine could raise neutralizing antibodies to levels even higher than those seen after the second dose.

"We believe this will reduce COVID-19 cases," he said. "We also believe that a third dose of mRNA-1273 has the potential to significantly extend immunity for much of the next year as we try to end the pandemic."

Informational documents from the FDA's analysis of Pfizer's booster application, released Wednesday, suggest that a key issue the agency will consider is whether the vaccine's protection is waning.

In its analysis, Moderna compared the vaccine's performance in more than 14,000 volunteers vaccinated between July and October 2020 with about 11,000 volunteers originally in the placebo group who were offered the injection between December 2020 and March 2021 after Your US Emergency Use Authorization

In the two-month period from July to August, researchers identified 88 cases of COVID-19 among those who received the two injections most recently, compared with 162 cases among those vaccinated last year. Overall, only 19 cases were considered serious, a key benchmark for assessing waning protection.