On Tuesday, Moderna (MRNA 3.06%) reported highly successful results from a clinical trial of its COVID-19 vaccine in patients ages 12 to 17. Depending on how you look at the top-line data from the TeenCove study, mRNA-1273 was found to be between 93% and 100% effective at preventing new cases.

The TeenCOVE trial enrolled over 3,700 12- to 17-year-old participants. Going by the primary case definition of COVID-19, from a period starting 14 days after their second dose, none of the volunteers who received the vaccine have tested positive. And although new case numbers are plummeting across the country, four of the volunteers who received the placebo did test positive for COVID-19.

A smiling scientist

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Since teenagers are far less likely to present symptoms of COVID-19 when they're infected, investigators also used a more sensitive definition of COVID-19 positivity that requires just one symptom plus a positive nasal swab test. Based on those looser criteria, the vaccine was still 93% effective at preventing new cases.

The TeenCove trial results Moderna reported Tuesday stack up nicely against those reported in March by Pfizer (PFE 0.11%) and BioNTech (BNTX 2.23%)for their rival mRNA vaccine, Comirnaty. That said, comparisons between the two teen trials should be taken with a grain of salt. Pfizer and BioNTech ran their U.S.-based clinical trial in 12- to 15-year-olds at a time when far more Americans were contracting the virus.

Moderna plans to submit a completed data package from the TeenCOVE study to the FDA in early June. Given that its top-line results are roughly in line with those that earned Pfizer and BioNTech a green light for their vaccine to be administered to teens, we can reasonably expect a similar response from the regulator within a few days of its receiving Moderna's submission.