Credit CDC
#15,747
The SARS-CoV-2 vaccine news continues this morning with a statement from Moderna on initial testing of their vaccine against both the UK and South African variants.
Using blood samples from 8 people who had received both doses of the moderna vaccine, and two monkeys that has been immunized, they measured levels of neutralizing antibodies to the two variants.
Not unexpectedly, for the UK variant they report:
For the B.1.1.7 variant, neutralizing antibody titers remained high and were generally consistent with neutralizing titers relative to prior variants. No significant impact on neutralization was observed from either the full set of mutations found in the B.1.1.7 variant or from specific key mutations of concern.Against the South African Variant, they report a 6-fold reduction in neutralizing antibodies, but still at levels high enough they still believe will convey protection.
For the B.1.351 variant, vaccination with the Moderna COVID-19 Vaccine produces neutralizing antibody titers that remain above the neutralizing titers that were shown to protect NHPs against wildtype viral challenge. While the Company expects these levels of neutralizing antibodies to be protective, pseudovirus neutralizing antibody titers were approximately 6-fold lower relative to prior variants. These lower titers may suggest a potential risk of earlier waning of immunity to the new B.1.351 strains.Because of this reduction in antibody response, the company plans to test new formulations that could be used as a booster shot against the South African variant. I've only reproduced an excerpt from the press release, so follow the link to read it in its entirety.
Moderna COVID-19 Vaccine Retains Neutralizing Activity Against Emerging Variants First Identified in the U.K. and the Republic of South Africa
January 25, 2021 at 8:28 AM EST
PDF Version
Out of an abundance of caution, Moderna launches clinical program to boost immunity to emerging variants
Manuscript posted to preprint server; company to host conference call once manuscript is available
CAMBRIDGE, Mass.--(BUSINESS WIRE)--Jan. 25, 2021-- Moderna Inc. (Nasdaq: MRNA), a biotechnology company pioneering messenger RNA (mRNA) therapeutics and vaccines, today announced results from in vitro neutralization studies of sera from individuals vaccinated with Moderna COVID-19 Vaccine showing activity against emerging strains of SARS-CoV-2. Vaccination with the Moderna COVID-19 Vaccine produced neutralizing titers against all key emerging variants tested, including B.1.1.7 and B.1.351, first identified in the UK and Republic of South Africa, respectively.
The study showed no significant impact on neutralizing titers against the B.1.1.7 variant relative to prior variants. A six-fold reduction in neutralizing titers was observed with the B.1.351 variant relative to prior variants. Despite this reduction, neutralizing titer levels with B.1.351 remain above levels that are expected to be protective.
This study was conducted in collaboration with the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). The manuscript has been submitted as a preprint to bioRxiv and will be submitted for peer-reviewed publication.
The two-dose regimen of the Moderna COVID-19 Vaccine at the 100 µg dose is expected to be protective against emerging strains detected to date. Nonetheless, Moderna today announced its clinical strategy to proactively address the pandemic as the virus continues to evolve.
First, the Company will test an additional booster dose of its COVID-19 Vaccine (mRNA-1273) to study the ability to further increase neutralizing titers against emerging strains beyond the existing primary vaccination series.
Second, the Company is advancing an emerging variant booster candidate (mRNA-1273.351) against the B.1.351 variant first identified in the Republic of South Africa. The Company is advancing mRNA-1273.351 into preclinical studies and a Phase 1 study in the U.S. to evaluate the immunological benefit of boosting with strain-specific spike proteins.
Moderna expects that its mRNA-based booster vaccine (whether mRNA-1273 or mRNA-1273.351) will be able to further boost neutralizing titers in combination with all of the leading vaccine candidates.
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