(Bloomberg) — Flu is widespread in 47 states and deaths from the virus and pneumonia are slightly above the epidemic level, though some regions may begin to see fewer cases, U.S. disease trackers say.

The Centers for Disease Control and Prevention report 20 children have died from the flu so far. The Atlanta-based agency doesn’t tally adult deaths until after the end of the season. Two children in New York have died from the flu, and more than 19,100 cases in the state prompted a public health emergency.

The influenza outbreak that prompted Boston to declare a health emergency has led to increasing hospital admissions and crowded emergency rooms in facilities around the country. Twenty-four states and New York City reported high levels of out-patient visits for flu-like illness, according to a surveillance report released yesterday. Sixteen states had moderate levels, five had low levels, and one, Hawaii, saw minimal levels of the illness.

“The bottom line: its flu season,” says Thomas Frieden, director of the CDC. “Most of the country has seen the flu and this will continue for a number of weeks.”

While flu activity remains high in the U.S. it may be decreasing, based on trends for the week Dec. 30 through Jan. 5, the CDC says. Flu activity in the South and Southeastern U.S. may soon be see improving conditions.

Influenza normally causes symptoms such as coughing, sneezing, headaches and body aches, fever, chills, and sometimes vomiting and diarrhea. Severe cases of flu are normally seen in very young and very old people whose immune systems are too weak to fight off the virus, and annual vaccination is recommended for vulnerable people and those who come into contact with them.

Flu outbreaks can occur as early as October in the northern hemisphere and peak in January or later. In the past 30-year period, most flu activity peaked in February, according to the CDC.

Anyone older than 6 months of age should be vaccinated, the CDC says. The effectiveness of the flu vaccine is estimated to be moderate at 62%, according to a report last week by the CDC.