New Delhi: Days after claiming promising results from its Covid-19 vaccine trial earlier this week, drugmaker AstraZeneca is now facing tough questions from experts, especially after the company admitted a manufacturing error by a contractor.Also Read - Covovax, Serum Institute of India's COVID Vaccine, Approved For 12-17 Age Group

As per updates, the error came to light after AstraZeneca, which is developing the potential Covid-19 vaccine in partnership with Oxford University, revealed different efficacy results from two different dose regimes. Also Read - Urgency Lost: Adar Poonawalla Warns Against Business-as-Usual Approach, Says 'Pandemic Not Behind Us Yet'

In the two different dose regimens vaccine efficacy was 90 per cent in one and 62 per cent in the other. The higher efficacy regime used a halved first dose and standard second dose. Two full doses showed lower efficacy. Also Read - Covishield Vaccine Price Revised For Private Hospitals, Check Latest Rate Here

A report in the New York Times on Wednesday suggested that AstraZeneca made a key “mistake” in the vaccine dosage received by some volunteers only after disclosing the preliminary results.

Along with the error, scientists and industry experts said a series of other irregularities and omissions in the manner in which AstraZeneca initially disclosed the data have also eroded confidence in the reliability of their results.

As it came to light that the vaccine’s most promising results did not reflect data from older people, it appears difficult that regulators in the US and elsewhere will quickly authorise the emergency use of the AstraZeneca vaccine.

On the other hand, Serum Institute of India on Thursday said the COVID-19 vaccine developed by AstraZeneca and Oxford University is safe and effective, and the Indian trials are progressing smoothly with strict adherence to all protocols.

The comments came after AstraZeneca and Oxford University acknowledged a manufacturing error that is raising questions about preliminary results of their experimental COVID-19 vaccine.

Asking people to be patient and not panic, the Serum Institute of India (SII) 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,” it added.

SII is conducting clinical trials of AstraZeneca-Oxford’s COVID-19 vaccine candidate in India.

“The Indian trials are running smoothly with strict adherence to all the necessary processes and protocols. So far, there are no concerns. However, we are going through the data that is available and will make further statement, if needed,” SII said.