The annual flu season kicked off at the end of November, with a surge in cases in parts of the country that could foretell a nasty spread of certain virus subtypes, according to the Centers for Disease Control and Prevention.

Four states report widespread flu activity, and 10 are reporting regional spread, as the predominant Influenza A H3N2 strain was noted in the 24 states reporting any flu activity, according to the latest CDC figures.

Georgia, Louisiana, Massachusetts, and Oklahoma all have widespread cases of the flu, health officials said. Regional rates of spread are seen in Arkansas, Connecticut, Kentucky, Maine, Mississippi, New Hampshire, North Dakota, Oregon, South Carolina, and Washington, as well as Guam.

Five pediatric deaths have been reported so far to the CDC, and there have been 566 hospitalizations due to flu that have been confirmed by laboratory tests.

But much could change before the season’s peak, which generally crests between now and February.

This year’s trivalent flu vaccine mixture was aimed at covering the H3N2 strain, which was first isolated and identified in the 1968 Hong Kong flu pandemic, resulting in 1 million deaths.

However, experts have said that the vaccine was not effective in Australia during this flu season, which is just now ending – and could be an indication of the viral spread here in the Northern Hemisphere.

Last month, a group of scientists from the University of Georgia and Sano Pasteur reported in the Journal of Virology that they had developed a “universal vaccine” for H3N2 strains. But that research is not yet clinically available.

Influenza kills an average of 36,000 people in the United States each year. Researchers continue to look for ways to attack the viruses – even through proteins long-lost in the process of evolution.