Updated: December 8, 2020 10:54:00 pm
An Oxford Vaccine Group researcher in a laboratory in Oxford, England, is working on the coronavirus vaccine developed by AstraZeneca and the University of Oxford. (AP)
The Oxford Covid-19 vaccine has been found to be safe, and only three of the 23,745 participants over a median of 3.4 months experienced serious adverse events that were possibly related to a vaccine.
All three participants have recovered or are recovering, and remain in the trial, said Professor Andrew Pollard of the University of Oxford, who is the study’s lead author, while addressing a virtual press conference after the publication of the interim results from Oxford. Covid-19 vaccine trials in The Lancet on Tuesday.
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The results are the first full peer-reviewed efficacy results to be published for a Covid-19 vaccine. According to the results, the vaccine protects against symptomatic disease in 70 percent of cases, with a vaccine efficacy of 62 percent for those who receive two full doses and 90 percent for those who receive half and then a full dose.
The Oxford vaccine uses a chimpanzee adenovirus viral vector that cannot cause disease in humans and expresses the SARS-CoV-2 spike protein. This means that the vaccine delivers the genetic code for the spike protein into the cells of vaccinated people, which then produce the protein, teaching the immune system to recognize and attack the virus.
Of 23,745 participants, 168 experienced a total of 175 serious adverse events during the period, but 172 events were not related to Covid-19 or control vaccines, Professor Pollard said. Those are events that the researchers deemed medically significant and ranged from a broken leg to a heart attack, he said.
One event occurred in the control group (one case of hemolytic anemia), one event was in the Covid-19 vaccine group (one case of transverse myelitis considered possibly related to the vaccine), and one case of severe fever was reported in South Africa. in a participant who recovered quickly without an alternative diagnosis and was not hospitalized. All three participants have recovered or are recovering and are still part of the trial, the study authors said in The Lancet.
Data from 23,745 adults in the UK, Brazil, and South Africa (11,730, 10,002, and 2,013 in the three countries, respectively) were analyzed. The interim analysis pools the data, providing greater precision for efficacy and safety results than is possible in individual trials and providing a broader understanding of the use of the vaccine in different populations, said Professor Pollard.
The main outcome of the study was to determine how many cases of symptomatic Covid-19 disease there were in participants who had received two doses of the vaccine (the first dose being the low or standard dose and the second the standard dose), compared to controls . Only cases that occurred 14 days after administration of the second vaccine (11,636 participants in the UK and Brazilian trials) were included.
There were 131 cases of symptomatic Covid-19 disease more than 14 days after the second dose of vaccine in these 11,636 people. This included 0.5% of cases in the vaccine group and 1.7% of cases in the control group, which equates to a vaccine efficacy of 70%. Cases of severe illness and hospitalization were controlled in the 23,745 participants. From 21 days after the first dose, there were 10 hospitalized Covid-19 cases, all in the control arm, and two were classified as serious, including one death. These are also secondary outcomes and will require further confirmation, said study co-author Professor Sarah Gilbert of the University of Oxford.
Despite the worldwide spread of Covid-19, a large proportion of the population in many countries has not been infected and is not immune. Vaccines can play an important role in increasing immunity, preventing serious disease and reducing health crisis, so the possibility that more than one effective vaccine will be approved for use in the near future is encouraging. Here, we have shown for the first time that an adenoviral vector vaccine, a type of vaccine technology that has been used since 2009, is effective and could contribute to disease control in the Covid-19 pandemic, “he said.
In a linked comment in The Lancet, Dr. Maria Deloria Knoll and Dr. Chizoba Wonodi, Johns Hopkins University Bloomberg School of Public Health, USA (who were not involved in the study), say: $ 2-3 per dose of Oxford-AstraZeneca with the COVAX facility holds good promise for equitable access for low- and middle-income countries, compared to the high cost of the two mRNA vaccines that have also reported an efficacy greater than 90% “.
“Despite the outstanding questions and challenges in delivering these vaccines, it’s hard not to be excited about these findings and now the existence of three safe and effective Covid-19 vaccines, with 57 more in clinical trials. With a range of manufacturers, a very large global investment in production and cooperation in procurement and distribution, it seems likely that in 2021 Covid-19 vaccines will be available to all countries in the world. Perhaps by this time next year, we can celebrate global control of SARS-CoV-2, in person, ”they said.
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