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After Pfizer and Moderna, the pharma company had recently released the results of the trials in UK and Brazil of it vaccine candidate AZD1222 which is a weakened version of a common cold virus (adenovirus). The results showed that the vaccine showed an efficacy of 90% was given as a half dose. In a full dose given as two does at least one month apart, there was 62% efficacy. And the combined analysis from both dosing regimens resulted in an average efficacy of 70 percent.
The company later said that the administration of half dose and later full dose was actaully an error. A report by Associated Press said tha the Oxford University on WEdnesday said in a statement that some of the vials used in the trial didnt have the right concentration of vaccine so some volunteers got a half dose. The university said that it discussed the problem with regulators, and agreed to complete the late stage trial with two groups. The manufacturing problem has been corrected, according to the statement.
What will happen now?
The company plans to run a new trial instead of adding an addition to the ongoing US trial. In this it will evaluate the lower dosage that performed better. As a relatively small number of people were adminsitered the low dose it is difficult todetermine the effectiveness. The AP report also says that the group also did not have volunteers over 55 years old. Since younger people have a bettern immune response, this is anotehr factor that needs to be cleared.
Serum Institute assures vaccine effective
After error came to light, Serum Institute of India which is conducting trials of the vaccine on Thursday said that the AstraZeneca and Oxford University vaccine is safe and effective, and that the Indian trials are progressing smoothly with strict adherence to all protocols. The company said in a statement, 'The AstraZeneca-Oxford vaccine is safe and effective. Even the lowest efficacy results are at 60-70%, making it a viable vaccine against the virus.That said, varied age groups with different dosage forms will result in slight variations and efficacy. We must be patient and not panic.'