Officials are warning against the dangers of the flu, which has already claimed the lives of 21 children — more deaths than this same timeframe last year — and the number is increasing.

In the week ending December 20, nearly 7 percent of deaths were blamed on pneumonia and flu. That’s higher than it was at the same time last year, but later on in the season the percentage of deaths blamed on the flu generally increases.

The number of children killed by the flu spiked tremendously in 2013. Thirty-seven deaths were blamed on the flu in the 2011 to 2012 season; the next season, 2012-2013, there were 171 deaths, the CDC says. In the 2013 to 2014 season, the figure was 109. (Totals are known for children but not adults because child deaths must be reported to the CDC; there’s no similar requirement for adult deaths.)

While the current stats are alarming, the latest statistics don’t indicate that the outbreak this year will be, overall, worse than in previous years, the Centers for Disease Control and Prevention says. It’s just too early to tell.

The CDC did release a map outlining flu activity. To date, nearly all states and Puerto Rico all have a high activity rating.

Even those vaccinated might not be safe, say reports. Just over half the strains tested were not covered by the vaccine. The biggest reason is a mutated strain that was not being spread at the time the vaccine was designed.