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November 19, 2020

AstraZeneca's COVID-19 vaccine develops strong immune response among older adults

Previous data demonstrated the inoculation generated antibodies and T cells in younger adults

Prevention COVID-19
AstraZeneca Oxford vaccine.png Rafael Henrique/SOPA Images/Sipa USA

In a phase 2 trial, AstraZeneca’s COVID-19 vaccine generated a T-cell response within two weeks of the first dose and an antibody response within 28 days of the booster dose.

AstraZeneca's COVID-19 vaccine has been found to safely develop a robust immune response in all adults – another encouraging sign on the immunization front. 

Preliminary findings of its phase 2 trial show the vaccine candidate caused few side effects in low and standard doses. Participants developed a T cell response within two weeks of the first dosage and an antibody response within 28 days of the follow-up dose.

The peer-reviewed study, published Thursday in The Lancet, consisted of 560 adults, including 240 over age 70. Previous data showed the vaccine generated a response in adults ages 18-55. 

The capability to develop an immune response in older adults is critical, because they are considered among the most vulnerable people to develop severe COVID-19 cases. They are expected to be among the people to receive a coronavirus vaccine once one becomes available. 

AstraZeneca, which has developed the vaccine with the University of Oxford, is currently conducting phase 3 trials to gauge the vaccine's efficacy. The phase 2 trial did not analyze that. 

Andrew Pollard, who heads the Oxford's vaccine trial team, told CNBC that researchers are "delighted with the results" and described the findings as "very encouraging."

"We hope that this means our vaccine will help to protect some of the most vulnerable people in society, but further research will be needed before we can be sure," co-author Dr. Maheshi Ramasamy added.

The study did, however, indicate some limitations. 

Participants in the oldest age group had an average age of 73 to 74 and few underlying health conditions. Almost all of the participants were white and non-smokers. 

The ongoing late-stage trials are said to have included participants from a range of backgrounds, countries and ethnicities.

The study comes on the heels of encouraging new efficacy data on the vaccines developed by Pfizer and Moderna.  

Pfizer’s vaccine is 95% effective against the coronavirus and will be submitted to the U.S. Food and Drug Administration for an emergency use authorization soon, the drugmaker said Wednesday.

On Monday, Moderna released preliminary findings showing its COVID-19 vaccine was 94.5% effective. The company also expects to apply for emergency use authorization later this year. 

AstraZeneca is planning to make the results from its late-stage COVID-19 vaccine trials available to regulators by the end of the year, meaning its vaccine could be available for distribution in early 2021.

Pfizer and Moderna each began Phase 3 trials for their COVID-19 vaccines in late July. Johnson & Johnson's vaccine also is in a late-stage trial. 

U.S. officials have suggested a coronavirus vaccine could become available in limited capacity late this year or early 2021, with widespread distribution to the general public not expected until sometime next spring.


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