Monday, November 23

The Oxford and Astrazeneca vaccine guarantees 99% immunity in older adults


The Oxford and Astrazeneca vaccine guarantees 99% immunity in older adults

Although this is good news, more tests still need to be done.

Photo: DAN HIMBRECHTS / EFE

The career of scientists and pharmacists for develop a 100% reliable vaccine that protects us from the coronavirus continues, and even more so when it seems that the pandemic has once again returned to its highest point.

This Thursday, November 19, the medical journal The Lancet He reported that in the second phase of clinical trials of the coronavirus vaccine developed by the University of Oxford and the AstraZeneca laboratory, it would guarantee immunity in older adults by up to 99% that, as a background, they are in good health.

The researchers tested the preparation, called ChAdOx1 nCoV-19, in an experiment with 560 healthy adults, including 240 over the age of 70, with the aim of observing its impact on the immune system and possible side effects.

The “promising preliminary results” indicate that this vaccine against the SARS-CoV-2 virus offers “similar safety and immunogenicity results in healthy older adults than those between 18 and 55 years old.”

According The Lancet, phase 2 allows to conclude that the antidote causes “few side effects” and “induces an immune response in both parts of the immune system in all age groups with both a low and standard dose.”

According to the study, British vaccine elicits a T-cell response (able to find and attack virus-infected cells) 14 days after the first dose, and an antibody response 28 days after the booster dose (that would attack the virus when it circulated through the blood or lymphatic system).

The authors note that phase 3 of the clinical trials, which is underway, should confirm these results and determine “to what extent the vaccine is effective in protecting against SARS-CoV-2 infection” in a larger and more heterogeneous group. of people, which includes elderly people with previous pathologies.

In the study released by the publication, which does not measure the effectiveness of the vaccine to protect from the virus, 560 adults (160 between 18 and 55 years old; 160 between 56 and 59 years old and 240 over 70) with good health received good the Oxford vaccine well a control antidote.

Volunteers over 55 years old were divided into two groups and received a single dose of the vaccine or two in a 28-day period.

All were observed from the beginning to detect adverse effects as well as the immune response.

The authors note that the side effects of ChAdOx1 nCoV-19 were “mild” (such as injection pain, fatigue, headache, fever, or muscle pain) although more common than with the control vaccine.

13 cases of severity were detected in the 6 months from the first dose but they are not considered related to vaccines.

The researchers explain that side effects were even less common in older than younger adults, and the immune response was “similar” in all age groups after the booster dose.

The vaccine induced antibodies against the coronavirus spike protein 28 days after a first low or standard dose in all age groups. After the booster vaccination, the antibody level increased 56 days after the start of the experiment, and the same happened with the neutralizing antibodies 42 days later.

For its part, the T-cell response against the coronavirus tip protein culminated fourteen days after the first inoculation, regardless of age or dose.

Researcher Sarah Gilbert says this study “answers some of the questions” raised by the World Health Organization (WHO) about the need for covid vaccines to protect older adults.

However, he points out, Other “questions about the efficacy and duration of protection” remain to be answered, and the vaccine should also be tested in older people with pathologies to ensure that it protects those who are most at risk of becoming seriously ill.

The authors acknowledge that their experiment “has limitations”, for example that the oldest people had an average age of 73 or 74 years and were healthy, which does not reflect the situation in nursing homes.

In addition, they add, the majority of volunteers of any age were white and non-smokers, so in the third phase of clinical trials, the tests will be extended to people of different backgrounds.

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