WEDNESDAY, Dec. 30, 2015 (HealthDay News) -- Anyone who hasn't had a flu shot this season should make a point to get vaccinated now, U.S. health officials advise.
Flu activity usually peaks in January or February, and flu can strike as late as May, according to the U.S. Food and Drug Administration. As long as the virus is circulating, it's not too late to receive a flu shot and protect yourself and others against this seasonal misery.
So far, the flu season has been mild, but U.S. health officials expect activity to pick up in the next few weeks.
"Influenza seasons and severity are often unpredictable. Annual influenza vaccination is the best way to prevent influenza among people 6 months of age and older," Marion Gruber, director of FDA's Office of Vaccine Research and Review, said in an agency news release.
"However, taking such practical measures as washing hands, covering coughs and sneezes, and staying home when sick can also help to decrease the spread and minimize the effects of flu," Gruber said.
Even healthy adults should be vaccinated every year, the agency said. Children and older people are typically at greatest risk for the flu and related complications, but flu viruses occasionally hit young and middle-aged adults hardest.
Last year, older Americans were hit particularly hard. Record numbers of seniors were hospitalized due to the flu, and by early March this age group accounted for the majority of deaths attributed to pneumonia and influenza, researchers from the U.S. Centers for Disease Control and Prevention reported.
Antiviral drugs -- such as Tamiflu (oseltamivir phosphate), Relenza (zanamivir) and Rapivab (peramivir) -- may help ease flu symptoms, but they are not a substitute for the seasonal flu vaccine, the agency said.
Virtually everyone older than 6 months of age is advised to get a flu shot. The exceptions are people with life-threatening allergies to flu vaccine or any ingredient in the vaccine. This might include gelatin, antibiotics, or other ingredients, according to the CDC.
And last year's flu shot won't help you now, experts cautioned. "Influenza viruses can change from year to year, due to different subtypes and strains that circulate each year," said Gruber.
That's why each year scientists produce a new flu vaccine that they predict will most closely match the viruses in circulation. Meanwhile, any protection provided by the previous year's vaccine wanes over time.
Developing an effective vaccine is a year-round effort. Each February global public health experts collect and analyze data from around the world to identify the flu viruses likely to cause the most illnesses the following flu season. Based on this analysis and the recommendations of an FDA advisory committee, scientists select the virus strains for inclusion in the seasonal flu vaccines used in the United States.
"The closer the match between the circulating strains causing disease and the virus strains in the vaccine, the better the protection against influenza," Gruber said.
The agency continuously monitors the safety of vaccines even after they are approved for use. This includes yearly surveillance for Guillain-Barre syndrome, a rare neurological condition associated with the 1976 flu vaccine.
In a typical season, flu complications -- including pneumonia -- send more than 200,000 Americans to the hospital. Death rates linked to flu vary annually, but have gone as high as 49,000 deaths in a year, the CDC says.
The U.S. Centers for Disease Control and Prevention has more about the seasonal flu vaccine.