Results from half doses
The results shared by Oxford-AstraZeneca revealed that the vaccine developers followed two dosage regimens during the trials and found strikingly different results from them. While one dosage regimen administered two full doses of the vaccine to the participants at least a month apart, the second one first administered half a dose to the participants and then gave a full dose to them at least a month later. In an interesting development, the first dose regimen, with two full doses, yielded an efficacy rate of 62%, and the second one with half and full doses resulted in a 90% efficacy rate.
Researchers are still examining the reason for this trend, but nonetheless, more efficacy due to a half and full dose regimen means that manufacturers would be able to vaccinate more number of people in the same limited supply because of lesser requirement per person. This will be especially helpful during the early stages of immunisation drive when the vaccine supply would be limited.
Moreover, the efficacy rate of 70% as demonstrated by Oxford-AstraZeneca is in any case better than most flu shots available, which give an efficacy of 40% to 60%.
Effectiveness in asymptomatic cases and across age groups
The preliminary results shared by Oxford-AstraZeneca showed that it had worked well across people of different age groups, including elderly people. Apart from that, the data also hinted at the vaccine candidate being able to reduce even asymptomatic infection. These are big advantages over the data shared by Pfizer and Moderna from their trials, the report added.
Based on further data, if it is found that the Oxford-AstraZeneca vaccine is better in preventing the symptomatic spread, then it could help governments in various countries to halt the virus in its tracks. Moreover, the fact that among 23,000 participants, no cases of severity or hospitalisation were reported is highly encouraging.
Better logistical requirements
Vaccines by both Pfizer and Moderna, if used in India, would need to be stored at sub-zero levels (-80 degrees Celsius and -20 degrees Celsius respectively), with Pfizer requiring almost cryogenic levels of storage. This kind of infrastructure is difficult to maintain in developing countries like India. On the other hand, the candidate produced by Oxford-AstraZeneca can be stored at normal refrigerated temperatures of between 2 degrees Celsius and 8 degrees Celsius, making the storage and distribution much easier, cheaper and faster.
For the vaccine by Oxford-AstraZeneca, the currently available normal supply chain system in countries like India would work well, as against Pfizer’s vaccine which would need specially designed dry ice-based thermal shippers.
Oxford-AstraZeneca has kept its vaccine significantly cheaper than others, having pledged not to make profits out of it. It has entered into agreements with international health organisations as well as governments as per which it would provide the vaccine at $2.50 per dose.
As against this, the Pfizer vaccine will cost around $20 for one dose, while that of Moderna would cost above $25.
Oxford-AstraZeneca’s vaccine production in India
Oxford-AstraZeneca entered into an agreement with Pune-based Serum Institute of India, as per which the SII is producing Covishield, a variant of the Oxford-AstraZeneca vaccine candidate. Covishield is conducting Phase 3 human trials in India at the moment, and this trial includes 1,600 participants. The results from the study here, coupled with the global results, could make the Oxford-AstraZeneca vaccine to be the first one to get regulatory approval in India.
Moreover, the results shared by Oxford-AstraZeneca could also be good news for Sputnik-V from Russia, which uses a technology similar to that of Covishield. Sputnik-V is also conducting human trials in India via Dr Reddy’s Labs from Hyderabad.
On the other hand, India does not yet have any firm agreement in place with Pfizer or Moderna for their vaccines.