Japan on Friday approved a drug that claims to kill the flu in 24 hours, a move that could be a major breakthrough in combating the way influenza is treated.

The Japanese drug maker Shionogi can begin selling its pill, called Xofluza, locally but it wouldn't hit U.S. shelves until at least 2019, the Wall Street Journal reports.

The price of the pill? Good question. The national insurer has yet to set one meaning that the drug may not be available in Japan until at least May, according to the Wall Street Journal.

That's unfortunate since the U.S. is in the grips of the worst flu season in a decade, with a total of 84 child deaths.

The flu remained widespread in 48 states, according to the CDC's latest report Friday. In the last severe flu season, during 2014-2015, 148 children died. The flu also killed an estimated 56,000 people, mostly older adults, that season.

Most of the children who have died this year, as in past years, have not been vaccinated. The CDC does not keep exact counts of adult flu deaths.

This year's flu vaccines are preventing about 36% of flu cases in vaccinated people but are working better, at a rate of about 59%, in young children, according to the CDC. The vaccines are about 25% less effective at preventing illnesses caused by the dominant virus behind this year's epidemic, CDC reported last week.