H1N1 was the big fear a number of months ago. But the flu season has arrived in the southern United States and New York City, and it is sure to spread to the rest of the country. The good news: There is still plenty of vaccine. but the vaccine protection takes about 2 weeks to kick in. Take the opportunity while you got the chance, advises a doctor of the U.S. Centers for Disease Control and Prevention (CDC). January and February typically are the worst flu months, and it can drag into March. This winter, a well-known strain of Type A flu is causing most of the illnesses so far in the United States. This so-called H3N2 branch of the flu family tends to trigger more pneumonia and other complications than other forms of influenza. This vaccine offers triple protection, against the swine flu known formally as Type A H1N1 flu, the worrisome H3N2 strain, and the Type B flu that tends to be less severe. The United States produced more than 160 million doses this year, a record amount. The CDC said the flu so far is striking very hard in parts of the South, including Alabama, Georgia, Louisiana, and Mississippi , and also in New York City. Illinois and Oklahoma also are reporting high levels of flu.