Moderna's COVID-19 vaccine gives immunity for at least 90 days, finds study

Moderna's mRNA-based vaccine, which it last month said was 94 percent effective, produces antibodies for at least three months, a study revealed. According to the study conducted by the National Institute of Allergy and Infectious Diseases (NIAID), the antibodies remained elevated for three months in all participants after booster shots were administered following fading of response after the first dose. 

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Immunity stays for 90 days

The study, published in the New England Journal of Medicine, said the antibodies had started to fade in participants days after the first dose, which was expected but were triggered again after the booster vaccination. The study was conducted on 34 healthy adults aged between 18 to 70 years, who were given two doses of vaccine 28 days apart. All participants received two injections of vaccine at a dose of 100 micrograms. 

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"At the 100-μg dose, mRNA-1273 produced high levels of binding and neutralizing antibodies that declined slightly over time, as expected, but they remained elevated in all participants 3 months after the booster vaccination. Binding antibody responses to the spike receptor-binding domain were assessed by enzyme-linked immunosorbent assay," the study noted. 

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The study said that serum neutralising antibodies were detected in all participants after 90 days. It said that Moderna's mRNA-1273 produced strong antibodies in younger participants than older patients, but added it still produced a strong immune response in all patients up to 70 years of age. The trial studies will be reviewed by the US Food and Drug Administration on December 17 before getting approval for emergency use authorisation. 

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