Research published yesterday in The Lancet suggests that the Oxford/AstraZeneca vaccine is safe and effective against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the disease COVID-19.
The Oxford/AstraZeneca vaccine – ChAdOx1 nCoV-19 – is approximately seventy percent effective in protecting against COVID-19. Analysing data from four ongoing clinical trials, researchers found that the vaccine “has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19.” Across two groups of participants, the vaccine had an approximate seventy percent effectiveness rate.
In the group who received two standard doses of the Oxford/Astra Zeneca vaccine, efficacy was 62.1 percent. In the group who received a low dose, followed by a standard dose, efficacy was ninety percent. Pooling the two groups, effectiveness registered at 70.4 percent.
As for safety, the analysis found “175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation.”
“Control of the pandemic will only be achieved if the licensing, manufacturing and distribution of these vaccines can be achieved at an unprecedented scale and vaccination is rolled out to those who are vulnerable,” said Professor Andrew Pollard of the University of Oxford, the study’s lead author. “Our findings indicate that our vaccine’s efficacy exceeds the thresholds set by health authorities and may have a potential public health impact.”
While the news seems good on the face of it, there are concerns about the extent to which the Oxford/AstraZeneca vaccine protects those above the age of 55 – a group at high risk from COVID-19. This warrants further investigation. As Marilynn Marchione, chief medical writer for the Associated Press, notes
“Independent experts have said the second group was too small — 2,741 people — to judge the possible value of that approach and that more testing is needed. The half-dose group also didn’t include anyone over 55, and among others in the study, only about twelve percent were in that age group. Older people also were enrolled later, so there hasn’t been enough time to see whether they develop infections at a lower rate than those not given the vaccine. It’s unclear if the results will be enough to lead regulators in the United Kingdom and elsewhere to approve its use right away.”
One of the study authors, Dr Merryn Voysey of the University of Oxford, said “the results presented in this report provide the key findings from our first interim analysis. In future analyses, with more data included as it becomes available, we will investigate differences in key subgroups such as older adults, various ethnicities, doses, timing of booster vaccines, and we will determine which immune responses equate to protection from infection or disease.”
What is indisputable is that a vaccine is the need of the hour. With more than 68,000 infections with SARS-CoV-2 till date and in excess of 1.5 million deaths, immunisation will be a key component in curbing the spread of COVID-19. In India, Prime Minister Narendra Modi has said a mass vaccination campaign will commence as soon as scientists give the go-ahead.
“Awaiting Corona’s vaccine,” Modi said recently. “As per my recent discussion with scientists, I hope there will be no more delay now.