The team is producing updated versions of the vaccine that more closely match strains circulating today.
The South Asian 2.3.2.1a clade is known to circulate in birds in India and Bangladesh.
Officials have identified a fill-and-finish opening on a production line at a vaccine company partner and said the activity won't disrupt the supply of seasonal flu vaccine.
Tests on an eye swab were positive in testing at the CDC, though respiratory samples were negative.
The child contracted the virus in India, which continues to report sporadic H5N1 outbreaks in poultry.
Among 49 jurisdictions with H5 virus testing capacity, 29 (59%) reported testing respiratory specimens from symptomatic people since January 2022.
The group will use the H5 probe to test samples from all 190 WastewaterSCAN sites and share the information with local public health officials and on its dashboard.
In other developments, H5N1 has been detected in cats from South Dakota with no known links to poultry or dairy herd outbreaks.
Federal officials said it's unclear if dairy cow outbreaks are peaking, and they haven't made much headway testing farm workers for avian flu virus.
Of the three newly confirmed outbreaks, two are in Michigan and one is in Idaho.
