Moderna’s COVID-19 vaccine generates immune response in older adults

Editor's Note

Preliminary findings in Moderna’s (Cambridge, Massachusetts) COVID-19 trial show the vaccine elicits strong immune system responses in older adults similar to responses in younger recipients, and adverse events associated with the vaccine are mainly mild or moderate.

In its expansion to include older adults, the trial enrolled 40 healthy volunteers: 20 adults aged 56 to 70 years and 20 adults aged 71 years and older. Half of each group received a lower dose of vaccine (25 µg), and half received a higher dose (100 µg). After 28 days, the volunteers received a second dose of the same vaccine at the same dosage.

The vaccine was well tolerated by all, though some experienced transient effects, including fever, fatigue, chills, headache, myalgia, and pain at the injection site.

The older volunteers exhibited a good immune response to the vaccine, with their blood containing robust binding and neutralizing antibodies against SARS-CoV-2, comparable to that seen in younger age groups. The vaccine also elicited a strong CD4 cytokine response involving type 1 helper T cells.

The 100 µg dose induced higher binding-and neutralizing –antibody titers than the 25 µg dose, which supports the use of the higher dose in a phase 3 vaccine trial, the researchers conclude.

The vaccine was co-developed by researchers at the National Institutes of Health’s National Institute of Allergy and Infectious Diseases.