The third dose will be administered at least 28 days following the two-dose regimen of the same vaccine to individuals 18 years of age or older (ages 12 or older for Pfizer-BioNTech) who have undergone solid organ transplantation, or who are diagnosed with conditions that are considered to have an equivalent level of immunocompromise, the agency said in a statement on Thursday.

“Our study adds to an increasing body of research that is looking at different aspects of how COVID-19 might be impacting the brain and brain function,” said study first author Adam Hampshire from Imperial College London in the UK.”This research is all converging to indicate that there are some important effects of COVID-19 on the brain that need further investigation,” Hampshire said.

Antibody levels are a good predictor for how effective Moderna Inc’s COVID-19 vaccine is, according to a new study released on Tuesday, a finding which could help speed up future clinical trials for vaccines against the disease.