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J&J begins largest Phase 3 study of a coronavirus vaccine.

The first of an expected 60,000 volunteers have received Johnson & Johnson's experimental coronavirus vaccine in a large-scale clinical trial launched Wednesday in the U.S., South Africa and a half dozen South American countries. 

The Phase 3 study, which would be the largest of any coronavirus vaccine trial if fully enrolled, will compare a single injection of J&J's vaccine against placebo. Early testing of the trial was "supportive" of further development, J&J said, indicating those results would soon be made available. 

With the trial start, J&J joins Moderna, Pfizer, AstraZeneca and several Chinese groups in evaluating how well their would-be vaccines protect healthy adults from developing COVID-19 or being infected with the new coronavirus SARS-CoV-2. Pfizer and Moderna are further along, and expect initial data in October and November, respectively.

While J&J's shot trails vaccine frontrunners in the U.S. and China by several months, the drugmaker's candidate could have similar important advantages, if testing proves it safe and effective. 

Unlike those developed by Moderna and Pfizer, J&J's vaccine is designed to be given as a single injection, which could aid what's likely to be a challenging process of vaccinating large swathes of the world's population. (That said, J&J does appear to be hedging its bets with a U.K. trial testing a two-dose regimen.) 

J&J's vaccine also appears to keep for longer at higher temperatures, lowering some of the distribution hurdles that could imperil vaccine roll-outs, particularly in more remote areas or regions with less equipped healthcare systems. 

The company said it expects the vaccine to be stable for two years when maintained at -20 degrees Celsius, and for at least three months when kept between 2 and 8 degrees Celsius, or roughly 35 to 45 degrees Fahrenheit. Both Moderna's and Pfizer's candidates are more temperature sensitive

J&J hasn't yet released data from the Phase 1/2 study that it ran in the U.S. and Belgium. In a statement Wednesday, the company said results from that trial would be released "imminently" in a draft manuscript to be posted on the pre-print server medRxiv. 

Early testing data from Pfizer, Moderna and AstraZeneca showed their vaccines were generally safe and spurred immune responses that researchers think could be protective. The larger, late-stage trials now underway aim to prove whether that's the case.


AstraZeneca, however, was forced to briefly suspend all study vaccinations with its shot after a participant in a U.K. study developed a neurological illness. Trials in the U.K. and Brazil have since restarted, but health authorities in the U.S. continue to investigate the case and AstraZeneca's study there remains on pause. 

Pfizer, which has enrolled more than 30,000 people into its Phase 3 study, has said the first results could come by late October, while Moderna expects its late-stage trial to produce data by the second half of November. 

While J&J did not give a timeline for how fast its trial may enroll and yield results, the company said it would have the first batches of its vaccine ready for distribution by early 2021 in the event of an emergency authorization. 

J&J estimates it can produce up to 1 billion doses of its shot each year and said it will distribute the vaccine, if safe and effective, on a not-for-profit basis during the pandemic.

Author:Ned Pagliarulo


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