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Pfizer, BioNTech Unveil Encouraging Early Vaccine Trial Results

FILE - A woman holds a small bottle labeled with a "Vaccine COVID-19" sticker and a medical syringe in this illustration taken April 10, 2020.

A new COVID-19 vaccine candidate has delivered promising preliminary data, U.S. pharmaceutical giant Pfizer and German biotech firm BioNTech announced Wednesday.

Within a month, treated subjects developed an antibody response to the coronavirus at or above levels found in blood from recovered COVID-19 patients, the companies reported.

The study was small, with 45 healthy adults ages 18 to 55. Subjects reported mild side effects, including pain at the injection site and low-grade fever, which are common vaccine reactions. The companies noted they didn’t know how long the immune responses would last, or what level of immunity humans need for protection from the virus.

Pfizer and BioNTech’s joint development program includes three other vaccine candidates, but Wednesday's, called BNT162b1, is the furthest along in the process. Researchers will use the preliminary data to pick from among the vaccine candidates and determine dosage for a significantly larger trial, involving up to 30,000 people. This next trial could start as soon as the end of the month if the project is approved.

More data this month

Pfizer and BioNTech said they could manufacture up to 100 million doses by the end of the year, and over 1.2 billion by the end of 2021. Data from a German trial of the same vaccine are expected to be released by mid-July.

At least 25 total COVID-19 vaccine candidates have progressed to human clinical trials, according to a vaccine development tracker by the London School of Hygiene & Tropical Medicine. Vaccines from Moderna, CanSino Biologics and Inovio Pharmaceuticals are among the most promising. No candidates have been approved for commercial use yet.

Tuesday marked six months since the World Health Organization received reports of mysterious clusters of pneumonia cases in China. Over 10.3 million cases of COVID-19 have been confirmed worldwide since.