Another vaccine with promising results had arrived.

However, scientists pointed out that previous trials suggest the vaccines are highly effective in the elderly.

AstraZeneca said on Monday that study participants in the United Kingdom had been given two different courses of the vaccine.

"Even if they (the regulators) chose to ignore the results of the low dose/high dose group, the study of the high dose/high dose patients will still be strongly significant, but I think that it unlikely", he said. These results gave an average of 70.4%, which meet the minimum threshold for a usable vaccine. Companies like BioNTech and Moderna are showing efficiency levels above 90% across the board, which immediately created some doubts about the wider range of the AstraZeneca figures. However, the incident has raised questions about the preliminary results of their experimental COVID-19 vaccine.

And in the days following that announcement, another point of confusion has emerged.

Sharma said they are dedicating even more people to the process for COVID-19, but said safety is a top priority when it comes to deciding if the vaccine can be used in Canada.

In a statement obtained by CNN, Oxford elaborated further, saying that a "difference in the manufacturing process" had led to the error.

The drugmakers informed the United Kingdom regulator of the issue when it was discovered, and it was agreed to complete the late-stage trial with two groups. The released data does not provide any differentiation between ages, sex, geographies, co-morbidities, body mass index, antibodies status prior to trial and after testing positive.

The university said in a statement that Phase-1 trials are ongoing.

The development is unlikely to hold up regulatory approval in the UK, Mr Soriot said. It is not clear if the FDA will authorize emergency use however. These special freezers are needed because the new COVID-19 vaccines from Pfizer and Moderna require lower storage temperatures than traditional vaccines - around -70 degrees celsius (-94 degrees Fahrenheit) versus 2-8 degrees Celcius (35-46 degrees Fahrenheit).

AstraZeneca presented an analysis of 23,000 participants in its Phase 3 trial.

However, AstraZeneca has acknowledged a key mistake in the vaccine dosage received by some study participants, the New York Times said in a report.

The Irish Government are bidding on vaccines through the European Union system. That a lower dose group was included in the trial was the result of a manufacturing error, as the developers admitted yesterday. Another dosing regimen showed 62% efficacy when given as two full doses at least one month apart. That could potentially affect the strength of AstraZeneca's findings, given that young people typically produce stronger immune responses to vaccines.

Britain has secured access to 100 million doses of the vaccine produced by the British drug manufacturer in partnership with the University of Oxford. They have declined about 7% this week amid questions about the trial results.

There's added pressure on the Astra shot to succeed because it's easier to store and the company is selling it at cost during the pandemic, which means many low- and middle-income countries are relying on it.

"I won't tell you we expected the efficacy to be higher", said Soriot. The stock is down 6.0% so far this week.