Enlarge AP Health authorities are urging nearly everyone to get vaccinated, and people 65 or older can choose to try a new high-dose version. HEALTH REPORTER TWEETS HEALTH REPORTER TWEETS Getting a flu shot will be far easier this fall than last, with retailers already stocking millions of doses and free shots available through Medicare and private insurance, officials say. Secretary of Health and Human Services Kathleen Sebelius says the federal Affordable Care Act mandates for the first time that Medicare and private health plans offer flu vaccine coverage without co-pays or deductibles. Uninsured children are covered under the federal Vaccines for Children program. "That will keep people healthy on the front end," Sebelius says. The elimination of cost as a barrier to vaccination comes at a key moment, with health officials now recommending that nearly everyone get a flu shot, except for children younger than 6 months and those with egg allergies. FIGHTING FLU: Families' stories FLU.GOV: Know what to do about the flu FLU SHOT Q&A: Get just one this year FINDING THE SHOT: What was your experience? Vaccine makers are even offering the first high-potency vaccine for those 65 and older, to see whether a stronger vaccine offers better protection to those with aging immune systems. This year's vaccine protects against 2009 H1N1, or swine, flu and the two other flu viruses that also are expected to cause disease this year. Three strains of flu have begun to spread in the USA, swine flu among them, health officials say. Roughly 60% of Americans are believed to be susceptible to swine flu — those who dodged the virus last year and weren't vaccinated against it. "We could still have a bad year," says Trish Perl, a flu expert at Johns Hopkins University Hospital in Baltimore. Ann Schuchat, director of the Centers for Disease Control and Prevention's National Center for Immunization and Respiratory Diseases, says no one can predict how the year will turn out, partly because no obvious pattern surfaced during winter flu season in the Southern Hemisphere. One of the three strains now circulating in the USA is H3N2, a variety often linked to more serious disease and death. "H3N2 hasn't really hit the U.S. in large numbers yet. We do think most people will be susceptible to this," Schuchat says. Fortunately, she says, this year's seasonal flu vaccine protects against H3N2. "We are recommending that when you see vaccine, get vaccinated. You don't have to worry, if you get vaccinated now, that you'll need another shot in January." Unlike last year, when the swine flu pandemic peaked before vaccine was widely available, the world's five flu vaccine makers three weeks ago began shipping out the first of nearly 165 million flu vaccine doses slated for use in the USA. About 30 million doses are now available through doctors' offices, pharmacies and other retailers, or will be soon. Navy surgeon Henry Lin of Bethesda, Md., has embarked on his own crusade to promote flu shots, an effort driven by personal tragedy. Lin's son, Trevor, 7, died Nov. 2 of swine flu after developing a secondary bacterial infection. At the time, flu vaccine was in short supply. Trevor, who had been healthy, didn't awaken enough concern in emergency room doctors to prompt them to prescribe Tamiflu, then often held in reserve for high-risk patients. About 30 hours after he left the emergency room, he collapsed and stopped breathing, Lin says. An autopsy revealed that, in addition to flu, he had developed a bacterial super-infection. "It's not just sick kids who are getting this. It's healthy kids," he says. Says Schuchat: "We can't perfectly predict who's going to have a horrible time with influenza and who isn't. A vaccine is the best way to protect against it. "No one wants to be in the shoes of that father." READERS: Since last year's swine flu vaccine was in short supply, health departments were forced to develop innovative ways of providing it. Did you have any trouble acquiring the flu shot last year? Describe your experience below. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more