Data shows antibody persistence for Moderna COVID-19 vaccine

By Jane Byrne

- Last updated on GMT

© GettyImages/Moonhonor
© GettyImages/Moonhonor

Related tags variant Antibody

Moderna today highlighted the publication of antibody persistence data out to six months following the second dose of its COVID-19 vaccine in The New England Journal of Medicine.

Stéphane Bancel, Moderna CEO, commented on the data: “This gives us further confidence in the protection afforded by our COVID-19 vaccine.”

Primary results from Phase 3 trial of the Moderna COVID-19 vaccine (mRNA1273) indicated 94% efficacy in preventing coronavirus disease. But, to date, the durability of protection was not known.

Now, new data shows durability of antibody response for the company's jab. 

study​ evaluated mRNA1273-elicited binding and neutralizing antibodies in 33 healthy adult participants in an ongoing the NIH-led Phase 1 trial, stratified according to age, at 180 days after the second dose of 100 mcg (day 209). 

As detected by three distinct serologic assays, antibodies elicited by the vaccine persisted through six months after the second dose, found the analysis. Antibody decay was estimated using two approaches and was consistent with published observations​ of convalescent patients with COVID-19 through eight months after symptom onset, according to the report. 

Studies monitoring immune responses beyond six months are ongoing, said the company.

The Moderna COVID-19 Vaccine is an mRNA vaccine against COVID-19 encoding for a prefusion stabilized form of the Spike (S) protein, which was co-developed by the US biotech along with investigators from the US National Institute of Allergy and Infectious Diseases’ (NIAID) Vaccine Research Center.

On December 18, 2020, the US Food and Drug Administration (FDA) authorized the emergency use of the Moderna COVID-19 Vaccine in individuals 18 years of age or older. Moderna has also received authorization for its COVID-19 vaccine from health agencies in Canada, Israel, the EU, the UK, Switzerland, Singapore, and Qatar. Additional authorizations are currently under review in other countries and by the World Health Organization (WHO).

Moderna is also pursuing a clinical development strategy against emerging variants. Additionally, NIAID, part of the National Institutes of Health (NIH), will conduct a Phase 1 clinical trial to assess the monovalent and multivalent modified mRNA-1273 vaccines as a primary series in non-vaccinated individuals and as a booster vaccine in those previously vaccinated with mRNA-1273.

Response duration from Pfizer BioNTech COVID-19 shot 

Updated analysis of Phase 3 clinical trial data, released by Pfizer and BioNTech last week, show the vaccine they codeveloped against COVID-19 (BNT162b2) has 91% efficacy for up to six months.

The findings, based on a vaccination regiment of two doses given three weeks apart, were the first to show the vaccine protects against symptomatic COVID-19 for that length of time. 

The companies reported efficacy of 91.3% against any symptoms of the disease in participants assessed up to six months after their second shot. These data also provided the first clinical results that a vaccine can effectively protect against the variant prevalent in South Africa, said the partners.

“It is an important step to further confirm the strong efficacy and good safety data we have seen so far, especially in a longer-term follow-up​,” said Ugur Sahin, CEO and co-founder of BioNTech.

“These data confirm the favorable efficacy and safety profile of our vaccine and position us to submit a Biologics License Application (BLA) to the US FDA,”​ said Albert Bourla, CEO, Pfizer. “The high vaccine efficacy observed through up to six months following a second dose and against the variant prevalent in South Africa provides further confidence in our vaccine’s overall effectiveness.”


From the 927 confirmed symptomatic cases of COVID-19 in the trial involving over 46,000 participants, 850 cases of COVID-19 were in the placebo group and 77 cases were in the BNT162b2 group, corresponding to vaccine efficacy of 91.3%, said the companies.

Thirty-two cases of severe disease, as defined by the CDC, were observed in the placebo group versus none in the BNT162b2 vaccinated group, indicating that the vaccine was 100% efficacious in this analysis against severe disease by the CDC definition; twenty-one severe cases, as defined by the FDA, were observed in the placebo group versus one case in the BNT162b2 vaccinated group, indicating 95.3% efficacy by the FDA definition, reported the developers.

Efficacy was generally consistent across age, gender, race, and ethnicity demographics, and across participants with a variety of underlying conditions, noted the partners.

In South Africa, where the B.1.351 variant is circulating and 800 participants were enrolled, nine cases of COVID-19 were observed, all in the placebo group, indicating vaccine efficacy of 100%, said the companies. “In an exploratory analysis, the nine strains were sequenced and six of the nine were confirmed to be of the B.1.351 lineage. These data support previous results from immunogenicity studies demonstrating that BNT162b2 induced a robust neutralizing antibody response to the B1.351 variant, and although lower than to the wild-type strain, it does not appear to affect the high observed efficacy against this variant.”

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