The results of phase 2 clinical trials of the vaccine against COVID-19 developed by the English University of Oxford and the pharmaceutical company AstraZeneca show that it is safe in healthy elderly people and causes a robust immune response in them, reports this Thursday the magazine The Lancet Medical .
Although this experimental vaccine is already completing phase 3 of clinical trials -the last one before marketing-, the data refer to the previous phase , in which it was administered to 560 healthy adults , including 240 over 70 years , in order to assess 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 in those between 18 and 55 years old,” say the researchers.
According to The Lancet, the results of phase 2 allow us to conclude that the vaccine causes “few side effects” and “induces a response in both parts of the immune system in all age groups with both a low and standard dose.”
According to the study, the British vaccine activates the two main arms of the immune system, since it generates a response from T cells (capable of finding and attacking cells infected by the virus) fourteen days after the first dose, and a antibody response 28 days after the booster dose (which would attack the virus as it circulates 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 heterogeneous group. of people , which includes elderly people with previous pathologies.
“Mild” side effects
The authors note that the side effects of the Oxford experimental drug were “mild” (such as injection pain, fatigue, headache, fever, or muscle pain). Thirteen serious cases were detected in the six months from the first dose but 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.
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 drug must still 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 studied had a mean age of 73 or 74 years and were healthy, which does not reflect the situation in nursing homes.
In addition, they add that the majority of volunteers of any age were white and non-smokers, so in the third phase of clinical trials they have extended the tests to people of different backgrounds and habits.
The study’s lead researcher, Andrew Pollard , wanted to make it clear that it is still too early to know in depth the efficacy of the vaccine, although he believes that the final results of the clinical trials will be available “in the coming weeks.”
“We are getting closer, and it will definitely be before Christmas, based on progress,” the director of the Oxford Vaccine Group told the BBC radio network in response to when the efficacy data and results would be released. of the study.
This vaccine project is based on an attenuated version of the chimpanzee common cold virus, which is characterized by its safety. If it finally proves its safety and efficacy, it could already be available even by the end of this year, since a part of its production began in parallel with clinical trials.
The European Commission (EC) signed a contract with AstraZeneca for the supply of up to 300 million doses of this vaccine, destined for the EU population. Spain has secured more than 30 million doses, of which it could receive an initial departure of three million this same month of December .