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The second phase of clinical trials of the vaccine against covid-19 developed by the English University of Oxford shows that is safe in healthy older people and elicits an immune response, reports this Thursday the medical journal ‘The Lancet’.
In collaboration with the pharmaceutical company AstraZeneca and other organizations, 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.
(Also read: Pfizer raises the effectiveness of its vaccine against covid-19 to 95%)
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 in those aged 18 to 55 years”.
According to ‘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 both with a low and standard dose.
According to the study, the British vaccine generates a T-cell response (capable of finding and attacking virus-infected cells) 14 days after the first dose, and an antibody response 28 days after the booster dose (which would attack the virus as it circulates through the blood or lymphatic system).
The authors point out 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 this Thursday, which does not measure the efficacy 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 the Oxford vaccine well a control antidote.
Volunteers over 55 years They 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 ChAdOx1 nCoV-19 side effects were “mild” (such as injection pain, fatigue, headache, fever, or muscle pain) although more common than with the control vaccine.
Thirteen serious cases were detected in the six months from the first dose but are not considered related to vaccines.
The researchers explain that the 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.
Induce an immune response in both parts of the immune system in all age groups with both a low and standard 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 shot, the level of antibodies 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 effectiveness and duration of protection” remain to be answered as well as the vaccine should 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 will extend the tests to people of different backgrounds.
EFE
