The Moderna COVID-19 vaccine will protect people for six months against the Delta variant studies have found.
With Delta running rampant across Australia and many countries around the world, scientists are looking for ways to protect people against the new strain.
The National Institutes of Health-led team in the United States of America tested blood from 24 fully vaccinated volunteers at several time points.
The first test was four weeks after the first dose of the Moderna vaccine, and then at three points after they were considered fully vaccinated with two doses up to six months out.
"At the peak of response to the second vaccine dose, all individuals had responses to all variants," the team wrote according to CNN.
The team found that two weeks after the second dose of the Moderna vaccine, all the blood samples neutralized all of the variants.
The Moderna vaccinee wasn't perfect though, with the Beta variant (B.1.351) - first seen in South Africa - most likely to elude immune protection.
Six months after the second dose, just over half of blood samples maintained antibodies that fully neutralized Beta variant samples. At the same time point, 96 percent of samples had full antibodies against the Delta variant, the team found.
Researchers found that there is only slight evidence that immunity deteriorates faster in older adults as they divided the blood samples into groups by age.
"Importantly, many subjects in the oldest group retained neutralizing activity against the variants six months after the second vaccine dose," they wrote.
Tests of the Pfizer's and Johnson and Johnson's vaccines also indicate they proved at least six months of immunity, and likely longer.