More promising mRNA vaccine data!
This time from Moderna. A new Phase II study shows that half-doses (50 μg) of our vaccine appear to be as effective as full doses (100 ug) at eliciting robust immune responses in the form of neutralizing antibodies.
https://www.sciencedirect.com/science/article/pii/S0264410X21001535

Participants were stratified into two age cohorts (≥18-<55 and ≥55) and were randomly assigned (1:1:1) to either 50 or 100 µg of mRNA-1273, or placebo administered as two intramuscular injections 28 days apart.

The primary outcomes were safety, reactogenicity, and immunogenicity assessed by anti-SARS-CoV-2-spike binding antibody level (bAb). Secondary outcome was immunogenicity assessed by SARS-CoV-2 neutralizing antibody (nAb) response. Participants had no history of infection.

Researchers found that anti-SARS-CoV-2 spike binding and neutralizing antibodies were induced by both doses of our vaccine within 28 days after the first vaccination, and rose substantially to peak titers by 14 days after the second vaccination, exceeding levels of convalescent

sera from patients previously infected with SARS-CoV-2. These antibodies remained elevated through the last time point which was assessed at 57 days. Neutralizing responses met criteria for seroconversion within 28 days after the first vaccination in the majority of participants,

with rates of 100% observed at 14 and 28 days after the second vaccination (this is why that booster is vital). It was found that binding and neutralizing antibody responses were generally comparable in participants who received the 100 μg dose and the 50 μg dose at all time

points and across both age groups. Another positive outcome of this study revealed that the safety profile of mRNA-1273 is acceptable as no serious adverse effects were observed. In short, the level of nAbs produced by our vaccine look extremely promising. This data was

disclosed before in FDA briefing documents but not displayed fully until now. Results support 2-dose regimens of 50 or 100 ug and confirm that a robust immune response is generated at both dose levels. Keep in mind, this is ONLY Ab response. This doesn’t even dive into

cellular immunity elicited by T-cells! I have written threads that focus on this in previously infected individuals. We would certainly need efficacy data on reduced doses but this gives insight into the robust immune responses produced by these vaccines!
https://twitter.com/sailorrooscout/status/1359946547887243265?s=21 https://twitter.com/sailorrooscout/status/1359520945753489409

Not to mention, with this data and of course some more efficacy studies, we could potentially be able to double the available vaccine supply. This could be a promising solution for vaccine shortages we are currently witnessing in several areas.