Oxford Vaccine Elicits Immune Response in Elderly

Oxford Vaccine produces strong immune response in elderly
Credit: University of Oxford, John Cairns.

According to the results from Oxford Vaccine’s phase 2 clinical trials, the vaccine is effective in eliciting an immune response in older adults aged 56 and above. 

Although 2020 has been quite a disaster so far, it seems November might finally turn things around for us. In the past two weeks, two US-based companies have announced promising results from their vaccine’s phase 3 trials. Moreover, today the Oxford Vaccine group announced encouraging results from their phase 2 clinical trials.

On 30th January, the World Health Organization (WHO) declared COVID-19 a public health emergency of international concern. Since then, researchers across the world have been searching for a safe and effective vaccine.

We were pleased to see that our vaccine was not only well tolerated in older adults; it also stimulated similar immune responses to those seen in younger volunteers. The next step will be to see if this translates into protection from the disease itself.

Dr. Maheshi Ramasamy, Investigator at the Oxford Vaccine Group 

The Oxford Vaccine – Made from Chimpanzees?

A team of researchers at the University of Oxford developed the vaccine using a weakened chimpanzee adenovirus. The adenovirus was genetically modified to include the surface spike protein of the SARS-CoV-2 virus. 

Once the vaccine enters the cells, the body starts producing the surface spike protein of the virus. The immune system then recognizes these proteins as foreign and starts producing antibodies. Thus, eliciting an immune response. These antibodies remain in the body for a long time, prepared to fight in case the coronavirus infects the body at a later time.

This particular vaccine technology not only generates a strong immune response but is also safer than other alternatives. Furthermore, high-risk individuals such as children, the elderly, and those with co-morbids, can also receive the vaccine. 

Older Adults Most at Risk

After a successful phase 1 trial, researchers began phase 2 with an aim of assessing the immune response in different age groups, specifically children and older people. They published their findings today in The Lancet.

According to research, adults aged 65 years and above have a 23-fold greater risk of dying from COVID-19 than those below 65. Furthermore, the highest number of hospitalizations occur among the elderly. Thus, placing older adults at a higher risk.

Researchers recruited 560 healthy volunteers aged 18 and above for their study. The participants were divided among three age groups: 18-55 years, 56-69 years, and 70 years. 240 study participants were aged above 70 years. 

Adults Over 70 Show Similar Results as Younger Age Groups

Two weeks after the booster dose, 208 out of 209 participants demonstrated antibodies in their blood. Furthermore, the immune response in those over 70 years was similar to those belonging to a younger age group. 

Inducing robust immune responses in older adults has been a long-standing challenge in human vaccine research. To show this vaccine technology is able to induce these responses, in the age group most at risk from severe COVID-19 disease, offers hope that vaccine efficacy will be similar in younger and older adults

Dr. Angela Minassian, Investigator at the University of Oxford 

The Oxford vaccine is currently undergoing phase 3 clinical trials. The team hopes to release its first interim analysis result in the coming weeks. 

Reference:

Ramasamy MN, Minassian AM, Ewer KJ, et al. Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial. :17. The Lancet. November 19, 2020, https://doi.org/10.1016/S0140-6736(20)32466-1

Mueller, Amber L et al. “Why does COVID-19 disproportionately affect older people?.” Aging vol. 12,10 (2020): 9959-9981. doi:10.18632/aging.103344

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