The flu is hitting younger and middle-aged adults unusually hard this season, but getting vaccinated reduces the need for a doctor's care, U.S. health officials said Thursday.
People aged 18 to 64 represent 61 percent of all flu hospitalizations this flu season, according to the U.S. Centers for Disease Control and Prevention. This age group accounted for only about 35 percent of flu-related hospitalizations the last three seasons, officials said at a CDC news conference.
"We think one of the reasons flu is hitting younger adults hard is that such a low proportion get a flu shot, even those with underlying conditions like asthma, COPD, and diabetes," said CDC Director Dr. Tom Frieden at the news conference.
"The bottom line is, influenza can make anyone very sick, very fast and it can kill. Vaccination every season is the single most important thing you can do to protect yourself," he added.
More deaths than usual have occurred among younger and middle-aged adults this season, too. People 25 to 64 years old have accounted for about 60 percent of flu deaths -- triple the rate for that age group three seasons ago, the CDC said.
Flu activity will likely keep up for several more weeks, especially in places where flu surfaced later in the season, the CDC officials noted. Southern states, especially Alabama, Louisiana, Mississippi and Texas, saw an early spike in flu activity this season. During January, flu activity decreased in the Southeast and South Central states but picked up in the West and Northeast, health officials said.
The currently circulating H1N1 virus, which is striking younger adults, emerged in 2009 and triggered a pandemic. H1N1 viruses have continued to circulate since the 2009 pandemic, but this is the first season since then that they have predominated in the United States, according to the CDC officials.
While flu hospitalizations are still highest among the elderly, adults aged 50 to 64 now have the second-highest hospitalization rate followed by children up to 4 years old. During the 2009 pandemic, people 50 to 64 years also had the second-highest hospitalization rate, the CDC said.
"Younger people may feel that influenza is not a threat to them, but this season underscores that flu can be a serious disease for anyone," said Frieden.
He stressed the value of vaccination. The current flu vaccine has cut the risk of needing medical care for flu-related problems by about 60 percent across all ages, he said, noting that's "encouraging."
However, by November, only one-third of 18- to 64-year-olds had been vaccinated. "That's why we're seeing more hospitalizations and deaths" in that age group, he noted.
Frieden said it's important to remember that some people who get vaccinated may still get sick. "People at high risk of complications should seek treatment if they get a flu-like illness. Their doctors may prescribe antiviral drugs if it looks like they have influenza," he explained.
Dr. Len Horovitz, an internist and pulmonary specialist at Lenox Hill Hospital in New York City, said six of his patients in the last three weeks -- mostly young adults -- who were vaccinated still had symptoms and tested positive for influenza after a nasal swab test.
He urged people who think they have the flu to see their doctors sooner rather than later if flu symptoms arise. "It's important to see a physician if it's in the first 24 to 48 hours because you can treat with [the antiviral drug] Tamiflu, even in people who have been vaccinated," said Horovitz.
People at high risk for flu complications include pregnant women, people with asthma, diabetes or heart disease, the morbidly obese and people older than 65 or younger than 5 years, but especially those younger than 2 years.
The CDC recommends that everyone 6 months and older get an annual flu vaccine. "This season vaccinated people were substantially better off than people who did not get vaccinated," Frieden said.
Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases, stressed it's not too late to get a flu shot.
"I want to remind you that the season is not over and things could change," she said at the press conference.
Horovitz said to prevent flu infection, practice good hand washing and avoid touching your face. Also, avoid kissing on the face when someone is sick, and steer clear of people who are coughing.
"If you're walking behind someone coughing who has flu, even outdoors, droplets are more sustained in cold air than warm air, so cover your face," Horovitz added.
Sourc - HealthDay
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For more on this year's flu, follow @CDCFlu on Twitter, or visit the U.S. Centers for Disease Control and Prevention.
CDC -Editorial Note
Update: Influenza Activity — United States, September 29, 2013-February 8, 2014
Influenza activity in the United States began to increase in mid-November and remained elevated and widespread as of February 8, 2014. During September 29, 2013-February 8, 2014, pH1N1 accounted for the majority of circulating influenza viruses, but influenza A (H3N2) and influenza B viruses also were identified. This season, influenza activity first increased in the southern states. By the end of December 2013, high influenza activity was seen throughout the United States. During the first 4 weeks of 2014, influenza activity decreased in the southeast and south central areas of the United States but began increasing in the west and northeast areas. Elevated influenza activity in parts of the United States is expected for several more weeks.
Surveillance data from previous influenza seasons have shown that the epidemiology of influenza is related to the circulating subtype, which can vary by season. This is the first season that pH1N1 has been the predominant influenza virus circulating in the United States since this subtype emerged in 2009. Although illness was seen in all age groups during the 2009 pandemic, persons aged 50-64 years had the highest influenza-associated death rate and second highest influenza-associated hospitalization rate among all age groups (2).
Preliminary surveillance data for the 2013-14 influenza season suggest that although overall disease prevalence is lower than during the 2009 pandemic, persons aged 18-64 years are again at relatively high risk for severe illness from influenza this season.
As of February 8, 2014, persons aged 18-64 years represented 4,077 (61%) of influenza-associated hospitalizations reported by FluSurv-NET. In contrast, during the past three seasons in which H3N2 or B influenza viruses predominated, persons aged 18-64 years accounted for only 35% (2012-13), 40% (2011-12), and 43% (2010-11) of all influenza-associated hospitalizations reported by
FluSurv-NET (Figure 4). For the 2013-14 season, cumulative influenza-associated hospitalization rates for persons aged 18-49 years (16.8 per 100,000) and 50-64 years (38.7 per 100,000) in FluSurv-NET have already surpassed the end-of-season rates from three of the previous four seasons (3).
During the three previous influenza seasons, the total number of P&I deaths reported through the 122 Cities Mortality Reporting System ranged from 37,444 to 41,708, of which <1% to 2% were deaths for which influenza was listed on the death certificate as an underlying or contributing cause of death. Although the age distribution of pneumonia deaths this season is similar to previous seasons, the age distribution of influenza deaths has changed. The number of influenza deaths during the current season (through February 8, 2014) among persons aged 25-64 years (352) exceeds the 138 deaths reported for that age group for the entire 2012-13 influenza surveillance season (September 30, 2012-September 28, 2013). This age group has accounted for approximately 62% of all influenza-associated deaths already this season, compared with 47% in 2010-11, 30% in 2011-12, and 18% in 2012-13 (Figure 4).
The more severe impact of pH1N1 on adults aged 18-64 years seen this season and during the pandemic is thought to result from at least two factors. First, persons in this age group likely lack the cross-protective immunity to pH1N1 seen in adults aged ≥65 years, which was likely acquired from past infection with antigenically related viruses (4). Second, preliminary vaccination coverage estimates for this season indicate that by early November 2013, adults aged 18-64 years had been vaccinated against influenza at a rate substantially lower (33.9%; 95% confidence interval [CI] = 31.9%-35.9%) than those aged 6 months-17 years (41.1%; 95% CI = 38.8%-43.4%) and ≥65 years (61.8%; 95% CI = 57.9%-65.7%) (5). In previous years, adults aged 18-64 years also have been less likely to receive influenza vaccine, compared with persons in other age groups (5). Although some persons infected with pH1N1 during the 2009 pandemic might retain some residual immunity, this protection has likely declined over time. Furthermore, seroprevalence studies showed that only a minority (approximately 35% of all ages combined) were seropositive for pH1N1 after the 2009 pandemic, with even smaller percentages (26%) among those aged 25-64 years (6).
Surveillance data available from the 2013-14 season are a reminder that, although some age groups are at increased risk of influenza complications every year (e.g., adults aged ≥65 years), influenza can cause severe illness in persons of any age, even in adults aged 18-64 years. Vaccination is the primary means to prevent influenza and its complications and is recommended annually for all persons aged ≥6 months. Data from the current and two previous influenza seasons suggest that vaccination reduced the risk for medical visits associated with influenza by 47%-61% (7,8). Health-care providers should continue to recommend and offer influenza vaccine for the remainder of the season to all unvaccinated persons aged ≥6 months.
Early and aggressive treatment of influenza with neuraminidase inhibitor antiviral drugs should be used when indicated, and data from this season show that pH1N1 remains susceptible to these agents. Currently circulating influenza A virus strains have shown resistance to amantadine and rimantadine, also known as adamantanes; therefore, adamantanes are not recommended for antiviral treatment or chemoprophylaxis of currently circulating influenza A virus strains (9).
Antiviral treatment is recommended as early as possible (ideally within 48 hours of illness onset) for patients with severe illness (e.g., patients hospitalized with influenza) or patients at high risk for serious influenza complications, including children aged <2 years, adults aged ≥65 years, and persons with certain underlying medical conditions (10).††† If treatment can be initiated within 48 hours of illness onset, antiviral medications also may be considered for outpatients with suspected or confirmed influenza who are not known to be at increased risk for developing severe illness (10).
Influenza surveillance reports for the United States are posted online weekly and are available at http://www.cdc.gov/flu/weekly. Additional information regarding influenza viruses, influenza surveillance, influenza vaccine, influenza antiviral medications, and novel influenza A infections in humans is available at http://www.cdc.gov/flu.
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