What is it like to be over 70?

Covid-19 Oxford-AstraZeneca vaccine apparently better tolerated by the elderly

Another success story regarding a potential corona vaccine: The team from Oxford University and pharmaceutical manufacturer AstraZeneca have submitted data from their phase 2 clinical trials on ChAdOx1. Accordingly, the vaccine candidate appears to be particularly well tolerated by older study participants. The study group of the over 70 year olds showed fewer side effects than that of the 18 to 55 year olds. The study appears in the renowned specialist journal "The Lancet".

Mild side effects very common

The tests with the candidate based on a so-called vector virus, which is also known by the abbreviation AZD1222, had to be interrupted at short notice in September. One study participant suffered from inflammation of the spinal cord. However, upon investigation of the case, it was found that it was unrelated to the vaccine.

Mild side effects, however, were common, most of them redness at the injection site, tenderness, headache, exhaustion or a feeling of fever. At the same time, the immune systems of all study participants showed reactions. 14 days after the first vaccination dose, the researchers found an increase in certain T cells. These are white blood cells that, in this case, were able to find cells infected by the virus in a test tube and turn them off. Neutralizing antibodies that blocked the virus directly were also found within 28 days of the second vaccination.

The vaccine has now been certified to be seventy percent effective. This makes it more effective than a typical flu vaccination, but lags behind the results of BioNTech / Pfizer and Moderna.

Previous studies often show poorer reactions in older people

Whether and to what extent the vaccine protects against a real infection with Sars-CoV-2 can only be shown by the phase 3 trials, which are already running. But co-author Maheshi Ramasamy from Oxford University says, referring to the results now published: "The robust antibody and T-cell responses in the older subjects are very encouraging. These people are among those who are at the greatest risk of severe Covid- 19 courses. I hope our vaccine will help protect these people. "

As a rule, older people respond less well to vaccines because their immune systems are generally less able to react. This was shown in three of the four other vaccine projects against corona that have already submitted data. This is also the case with the two Chinese candidates from CanSino and Sinopharm, as well as the German-American RNA vaccine from BioNTech / Pfizer, that older participants showed fewer immune responses. Only Moderna found similarly strong immune reactions from younger and older participants in its RNA vaccine test in the laboratory. However, it is difficult to compare the studies with one another, so care should be taken when interpreting the data.

Strong focus on older participants at Oxford University / AstraZeneca

The duo University of Oxford and AstraZeneca has specifically recruited older test participants for its current phase 2 test in order to counteract the problem that seniors are usually underrepresented in such tests and are therefore less known about their effectiveness and side effects. The vaccine candidate ChAdOx1 was tested on 160 people aged 18 to 55 years, 160 people between 56 and 69 years old, and on 240 people aged 70 and over. Because participants were recruited during the UK lockdown, only people with no pre-existing medical conditions took part.