What to know about the Moderna vaccine for young children

Some families of young children have eagerly anticipated coronavirus vaccines. (Matt Roth for The Washington Post)

Drugmaker Moderna announced Wednesday it would soon seek authorization for its coronavirus vaccine for young children, toddlers and babies after a clinical trial showed the vaccine was safe and triggered an immune response against the virus.

But the results, presented in a news release, were more complicated to interpret than previous trials — a reflection of how the emergence of variants has complicated the pandemic.

Coronavirus vaccines performed spectacularly well against the original version of the virus circulating in 2020, preventing most illness and infections in adults. But the virus has evolved, and those same shots provide far less protection against omicron infections in adults. The same was true for the children in Moderna’s trial, who were between 6 months and 5 years old.

Regulators will spend the coming weeks scrutinizing data and details, and will make the call on whether the vaccine is safe and effective in children. Here’s what we know about the vaccine so far and the next steps.