The flu virus that four years ago proved especially deadly to younger people is back in force this season, prompting health officials to renew their annual call for the public, particularly children and pregnant women, to get vaccinated.
In an unusual move, the state is even picking up the cost of flu shots for pregnant Medicaid beneficiaries.
The current flu vaccine fights the H1N1 virus, popularly called "swine flu," the strain that dominated the 2009-2010 season and was blamed for an estimated 12,470 deaths in the United States.
The total number of flu-related deaths that year wasn't especially high in comparison with other years. But what was different was that most of the hospitalizations and deaths were in patients under age 64, according to the Centers for Disease Control and Prevention. That was largely because younger people had never been exposed to the unusual H1N1 strain, making immunization even more critical.
"Go out there and get the flu shot," said Seyi Omaivboje, an epidemiologist with the Florida Department of Health in Hillsborough County. "That's still our message."
Nationwide, the H1N1 virus has been the dominant strain detected in laboratories this season for the first time since the 2009-2010 season. Since October, there have been more than 1,580 confirmed cases of flu-associated hospitalizations. Six children have died of complications, according to the CDC.
Officials do not track adult deaths from the flu, which makes gauging the impact difficult. But in Pasco County, two H1N1-related deaths have been confirmed in recent weeks. One was an unidentified adult man and the other was 27-year-old Holly Harrelson of Ridge Manor, whose family said she had otherwise been healthy.
Following reports that one pregnant woman in Florida has died and at least four other pregnant women hospitalized because of flu this season, the state's Medicaid program has decided to pay for vaccinations for nearly 65,000 pregnant enrollees through the end of March, according to Shelisha Coleman, spokeswoman for the Agency for Health Care Administration.
Pregnant women can be especially vulnerable to the flu. During the 2009-2010 season, the CDC recorded nearly 60 deaths of pregnant women nationally. In the Tampa Bay area, at least two pregnant women died, a 24-year-old from Citrus County and 22-year-old from Hillsborough.
Medicaid typically covers vaccinations only for children and young adults up to age 21. Officials temporarily added pregnant women after the Florida Department of Health received reports about the fatality and the hospitalized women, none of whom had been vaccinated.
Citing patient confidentiality, Health Department spokesman McKinley Lewis declined to say where those women live and emphasized there may be even more such cases, since hospitals are not required to report flu in adults.
The flu vaccine has long been considered safe for pregnant women and their fetuses. U.S. health officials began recommending flu shots for them more than five decades ago after pregnant women died at a higher than average rate during a flu pandemic in the late 1950s.
Medicare, the public insurance program for seniors and the disabled, has picked up the tab for flu shots since 1993. Private insurance plans vary, but under the Affordable Care Act, most policies must cover the flu vaccine at no cost.
The price of a flu shot at pharmacies runs around $30.
Michael Jhung, a medical epidemiologist with the CDC, said it's unclear why H1N1 has become the dominant strain this year. "Since 2009, we've seen it every year but just not to the extent that we've seen it this year," said Jhung.
Jhung noted that pregnant women are susceptible every flu season, but said Florida's decision to pay for pregnant Medicaid recipients' vaccinations reflects the H1N1's historical impact on younger people.
Vaccines do not guarantee you won't get flu, but if you do, it will likely be a less severe case, experts say.
Another group that benefits especially from flu shots is people with asthma and allergies, said Dr. Richard Lockey, an allergy and immunology specialist with University of South Florida Health.
Because of existing inflammation, asthmatics and allergy patients are susceptible to viruses, including the flu, he said. Allergy season is about to take off with cypress, cedar and bayberry trees already pollinating for the last month and oaks getting started.
"We have so many people who reject the flu vaccination," he said. "It's almost incomprehensible."
Lockey's clinic has been open late in recent days to accommodate all the patients who got sick over the holidays. He's seen people with bad colds and flu.
"Is it worse than usual? Probably not," he said. "But after a while, you don't look forward to this time of year as a doctor."
Jodie Tillman can be reached at firstname.lastname@example.org.