What we know about the flu season so far: ANALYSIS The worst of the 2018-2019 flu season may be yet to come.

The new year may have just begun, but the 2018-2019 flu season is well underway.

Across the U.S., outpatient clinic visits for flu-like symptoms during the last full week of December are double what they would be during a typical week outside of flu season.

Almost 6 percent of patient samples sent to the lab from Sept. 30 through December have been flu-positive, according to the Centers for Disease Control and Prevention. However, in the week preceding New Year’s Eve, that figure jumped to over 13 percent.

Flu rates typically peak in the U.S. between December and February. If you haven’t already received the flu shot, there’s no better time than now to protect yourself and your loved ones by getting the vaccine. People who are at most risk for flu complications include children, pregnant women, people over 65, those with chronic medical conditions and nursing home residents. In these cases the flu vaccine could be life-saving.

Influenza A (H1N1) is currently the most common strain of the flu virus in the U.S., and the 2018-2019 vaccine provides protection against this strain. The H3N2 strain, seen predominantly in the southeast, is also covered by the vaccine. The flu shot is available in doctor’s offices and drugs stores, and the CDC continues to recommend vaccination through January and even later. Once vaccinated, it typically takes two weeks for the body to develop antibodies.

The majority of states are experiencing low to moderate flu activity, although 19 states are seeing higher levels of flu, particularly the South and Southwest. Almost half of all states have flu cases in at least half of their counties. There are currently over five flu-related hospital admissions for every 100,000 Americans.

Children under 5-years-old have the highest likelihood of being hospitalized for the flu; so far there have been 13 pediatric deaths from the flu in the 2018-2019 season.

Overall deaths from flu and pneumonia, however, are not at epidemic levels this season. The current number U.S. flu deaths per week is around 40. It’s important for every member of a household to get the flu vaccine in order to protect the whole family. Regular hand washing also plays a key role in preventing the spread of bacteria and viruses.

Anyone with flu symptoms should stay home from work or school to prevent the spread of flu. Contact your provider to see if antiviral flu treatment is needed. There are currently 4 FDA approved medications to treat the virus for the 2018-2019 flu season.

Dr. Naomi Kaplan is a resident physician in physical medicine and rehabilitation, and a member of the ABC News Medical Unit.