Oct. 27 (UPI) -- A late-stage human clinical trial for Pfizer's COVID-19 vaccine candidate is close to full enrollment, the drugmaker announced Tuesday.
Pfizer said it has so far enrolled more than 42,000 participants, about 36,000 of whom have already received a second dose of the BNT162 "messenger RNA"-based vaccine.
Pfizer is partnered with German drugmaker BioNTech to develop the candidate, one of several in development worldwide to reach final, third-stage trials.
Last month, Pfizer and BioNTech expanded target enrollment to 44,000, up from 30,000 participants. The move, Pfizer said, "allows the companies to further increase trial population diversity," including those with chronic diseases including human immunodeficiency virus (HIV) and Hepatitis B or C.
Moderna announced last week that it has reached full enrollment of 30,000 in its late-stage trial for a vaccine.
The companies received permission this month from the Food and Drug Administration to enroll adolescents as young as 12 in the trial. A week ago, they said a vaccine won't be available until the middle of November, at the soonest.
Pfizer and BioNTech held exploratory talks with the European Union last month for a proposed supply of 200 million doses of BNT162 to member states, with an option for an additional 100 million doses. If the vaccine is ultimately approved, deliveries could begin by the end of the year.
Pfizer said last month scientists should know sometime in October whether the vaccine candidate works.
The companies also have distribution agreements with Canada and Japan.
Pfizer's BNT162 candidate is one of a number of possible vaccines in development worldwide. Click here for our COVID-19 vaccine tracker.