AstraZeneca COVID-19 Vaccine Triggers Robust Immune Response In Older Adults, Peer-Reviewed Study Says

British pharmaceutical giant AstraZeneca plc's AZN COVID-19 vaccine developed in collaboration with the University of Oxford is safe and triggers a similar immune response among all adults, as per the preliminary findings of a peer-reviewed phase two trial, CNBC reports.

What Happened: The peer-reviewed study of 560 participants — 160 aged 18–55 years, 160 aged 56–69 years, and 240 aged 70 years and older — found that immune response among people aged 56-years and higher is the same as that in the 18-55 years age range. 

AstraZeneca had previously said that interim data showed their vaccine had produced an immune response in older and younger adults.

The vaccine produced a "T-cell response" within 14 days of the first dose and an antibody response within 28 days of the booster dose. T-cell responses will play a role in long-term immunity against the virus, CNBC noted.

The phase two trials did not confirm the vaccine's efficacy, but the ongoing phase three trials' results are expected this year.

Why It Matters: The co-author of the study at Oxford University, Dr. Maheshi Ramasamy, told CNBC that T-cell responses among older adults were "robust and encouraging" as older adults and people with existing health conditions are at the greatest risk of serious COVID-19 disease.

Recently, Pfizer Inc. PFE said that its vaccine was 95% effective in preventing COVID-19, and Moderna Inc MRNA confirmed that its vaccine has 95% efficacy.

Price Action: AZN shares closed lower by 1.76% at $53.99 on Wednesday.