The first study to directly compare immune reactions between Pfizer’s and AstraZeneca’s Covid-19 vaccines found strong and broadly similar antibody responses in over-80-year-olds after a first dose of either shot, scientists said on April 14.

Pfizer and BioNTech on March 31 announced data from a Phase III study which showed 100 percent efficacy and robust antibody responses in patients ages 12-15 years old who received the BNT162b2 vaccine.

Moderna believes the company’s Covid-19 vaccine protects against new variants found in Britain and South Africa, although it will test a new booster shot aimed at the South Africa variant after concluding that the antibody response could be diminished.

Roche is partnering with Moderna to include a Covid-19 antibody test in the mRNA specialist’s ongoing vaccine trials, the Swiss drugmaker said, potentially demonstrating if the vaccine is working.

The U.S. Food and Drug Administration gave Emergency Use Authorization (EUA) to a Covid-19 test developed by Roche that measures antibodies within the blood.