The vaccine from the pharmaceutical company Pfizer to prevent COVID-19 can be effective in more than 90%, a result much higher than expected.
This was confirmed this Monday by the pharmacist itself, which is in phase 3 of the study.
The announcement
does not mean that the coronavirus vaccine is imminent
, although the company could file an emergency use request with US health regulators later this month.
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This interim analysis, from an independent data monitoring board, examined 94 infections recorded so far in a study that has recruited nearly 44,000 people in the United States and five other countries.
Pfizer Announces Promising Results in Testing its Experimental COVID-19 Vaccine
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Pfizer did not provide further details on those cases, warning that the initial protection rate could change by the time the study ends.
Even the disclosure of that initial data is highly unusual.
"We are in a position to offer some hope," Dr. Bill Gruber, Pfizer's senior vice president of clinical development, told The Associated Press.
"We are very excited," he added.
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Authorities have emphasized that any vaccine is unlikely to arrive long before the end of the year and that the limited initial supplies will be rationed.
Vaccines manufactured by Pfizer and its German partner BioNTech are among the top 10 potential vaccine candidates in advanced testing worldwide;
four of them so far in huge studies in the US Another American company, Moderna Inc., has also said it hopes to apply to the Food and Drug Administration (FDA) later this month.
Pfizer does not plan to stop its study until it records 164 infections among all volunteers, a number the FDA has agreed is enough to tell how well the vaccine is working.
The agency has made it clear that any vaccine must be at least 50% effective.
No participant so far has become seriously ill, Gruber said.
It was also unable to provide a breakdown of how many of the infections have occurred in older people.
The FDA has required that US vaccine candidates be studied in at least 30,000 people.
In addition to an adequate number of older adults, those studies should also include other high-risk groups, including minorities and people with chronic health problems.
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The agency also told companies that they should follow half of the participants for side effects for at least two months, the period of time when problems typically arise.
Pfizer hopes to reach that milestone by the end of this month, but said no serious safety concerns were reported Monday.
Because the pandemic is still raging, manufacturers hope to ask governments around the world for permission for emergency use of their vaccines while further testing continues, allowing them to get to market faster than normal, but raises concerns about how much scientists will know about these vaccines.
With information from AP.