After the trial results showed that the Moderna COVID-19 vaccine has an efficacy rate estimated at 94.1 percent, the developers had filed requests for emergency authorization of the vaccine with US regulators and also asked the authorities of Singapore to use the shot. But a study showed that it can help antibodies last just for three months.
The National Institute for Allergies and Infectious Diseases (NIAID) researchers which co-developed the vaccine, studied the immune response of 34 adult participants of the first stage of a clinical trial, including young and old individuals. They found that the Moderna vaccine causes the immune system to produce potent antibodies that endure for at least three months.
The vaccine will be reviewed by an advisory committee of the Food and Drug Administration (FDA) in the US on December 17, after which it could receive an emergency approval.
Moderna, Pfizer and AstraZeneca
As per the World Health Organization, a minimum of six months would be acceptable. But NIAID researchers wrote in the New England Journal of Medicine that the antibodies against the novel Coronavirus declined slightly over time. But according to the researchers, the antibodies remained elevated in the participant three months after the booster vaccination. The mRNA-1273 vaccine is administrated 28 days apart in two injections.
Dr. Anthony Fauci, NIAID director, and other experts said that it is very likely that the immune system will remember the virus in case of re-exposure and then produce new antibodies. The study also showed that the Moderna vaccine activated a certain type of immune cell that should help out in the so-called memory response. But to confirm that, long-term study is required.
In terms of the Pfizer-BioNTech COVID-19 vaccine, UK became the first country to approve the vaccine for widespread use. When it comes to the immune memory, it is hard to say at this point, as the clinical trials were not set up to answer that particular question. It will become clear in the coming months as the volunteers continue to be monitored.
But as per Uğur Şahin, the chief executive of the German company BioNTech that co-developed the vaccine with US drug giant Pfizer, he expects protection to last "months or even years".
The University of Oxford and pharmaceutical company AstraZeneca vaccine is hoped to prevent COVID-19 infection for 12 months. Mene Pangalos, AstraZeneca's executive vice president of biopharmaceuticals R&D said that the vaccine has been engineered specifically to have "what we call a long half-life, (so) we think they will confer protection for (at least) six, but more likely closer to 12 months."