LOS ANGELES — So many people have fallen sick with influenza in California that pharmacies have run out of flu medicines, emergency rooms are packed and the death toll is rising higher than in previous years.

Health officials said Friday that 27 people younger than 65 have died of the flu in California since October, compared with three at the same time last year. Nationwide and in California, flu activity spiked sharply in late December and continues to grow.

The emergency room at UCLA Medical Center in Santa Monica typically treats about 140 patients a day, but at least one day this week had more than 200 patients —mostly because of the flu, said the ER’s medical director, Dr. Wally Ghurabi.

“The Northridge earthquake was the last time we saw over 200 patients,” Ghurabi said.

Experts say it’s possible that this year’s flu season is outpacing the last simply because it’s peaking earlier.

The flu season is typically worst around February, but can reach its height anytime from October to April. Though influenza had only killed three Californians at this time last year, it had taken 68 lives by the end of February, according to state data.

California doctors, however, contend that the recent surge has been unusually severe.

“Rates of influenza are even exceeding last year, and last year was one of the worst flu seasons in the last decade,” said Dr. Randy Bergen, clinical lead of the flu vaccine program for Kaiser Permanente in Northern California.

State health officials said Friday that there was no region of the state where people were being spared from the flu.

In Riverside and San Bernardino counties, ambulance services have been severely strained because of the number of flu calls coming in, local health officials said.

Plus, emergency rooms are so crowded that ambulances arriving at hospitals can’t immediately unload their patients, so they’re unable to leave for incoming 911 calls, said Jose Arballo Jr., spokesman for the Riverside County Department of Public Health.

“The ambulances have to wait, and if they’re waiting there, they can’t be out on calls,” Arballo said.

Most people in California and nationwide are catching a strain of influenza known as H3N2, which the flu vaccine typically doesn’t work as well against. National health officials predict the vaccine might only be about 32 percent effective this year, which could be contributing to the high number of people falling ill.

H3N2 is a dangerous strain of the flu, experts say.

“It tends to cause more deaths and more hospitalizations than the other strains,” said Dr. Jeffrey Gunzenhauser, L.A. County’s interim health officer.

Of extra concern this year are large numbers of older patients who are showing up at hospitals with the flu and pneumonia, a potentially fatal combination.

“You have no choice but to admit them and hydrate them on IV antibiotics to prevent —God forbid — a bad outcome,” Ghurabi said.

Each year, the number of flu deaths reported by the state includes only people younger than 65 and therefore underestimates the toll of the flu, since elderly people are most likely to succumb to the illness, experts say. In Los Angeles County, 33 people have died of the flu this season and only a handful were under 65, Gunzenhauser said.

Dr. Matthew Mullarky, an emergency physician at St. Joseph Hospital in Orange, said that half of the patients he saw on a recent ER shift were so sick that he had to keep them in the hospital. Most of them were older than 85, with the flu and pneumonia.

“It’s incredibly scary,” he said.