Influenza has officially reached epidemic proportions in the United States,  the flu season hit the US early and hard. Twenty children have died from the virus that has swept across most of the country, there are vaccine shortages and New York Govenor Andrew Cuomo has declared a state of emergency. There have already been five times as many cases reported in New York as there were in the entire flu season last year, and it’s not clear if the season has yet peaked.

The early start and fast spread of flu this season – especially after 2011-2012’s very mild outbreak – has overwhelmed doctors’ offices and hospitals, forcing some patients to wait through the night to be seen in emergency departments.

Nine of the 10 U.S. regions had “elevated” flu activity last week, confirming that seasonal flu has spread across the country and reached high levels several weeks before the usual late January or February, CDC reported.

The Australian Medical Association president Steven Hambleton said the overseas experience was a “forewarning” for Australia.

“Last time the flu season peaked early (in the US) there were 50,000 deaths,” he said.

While flu vaccines offer protection, they are not failsafe.

This year’s flu vaccine is 62 percent effective, scientists reported in a CDC’s publication early January, meaning that almost four in 10 people who receive the vaccine and are exposed to the virus will nevertheless become infected. This is considered “moderate” effectiveness and is in line with previous years’ flu vaccines, which range from 50 percent to 70 percent effective, Dr. Joseph Bresee, chief of the CDC’s influenza division, told reporters.

Experts recommend the vaccine for everyone over 6 months of age. Even if it does not prevent flu, immunization can reduce the severity of the illness, preventing pneumonia and other life-threatening results of flu.

For the latest updates on the United States Flu Epidemic view the CDC Weekly Update.

---