Every year, millions of Americans get sick with the flu. While the vast majority of people will recover without any serious complications, not everyone is so lucky.
Over the course of a typical flu season -- which runs from October to May in the United States -- hundreds of thousands of people are hospitalized with the virus and tens of thousands die from it, according to the Centers for Disease Control and Prevention.
Although no seasonal flu vaccine is 100% effective (last year's vaccine was just 42% effective), it is still the best way to prevent infection. The CDC recommends that everyone 6 months and older get vaccinated every year.
However, not everyone in that range has been able to get the vaccine to date. In the past, people with egg allergy were advised to explore egg-free flu vaccination options.
Most flu vaccines administered today are manufactured using chicken eggs and contain trace amounts of a protein called ovalbumin.
But a paper published Tuesday in the Annals of Allergy, Asthma and Immunology found the flu shot to be safe and recommended its use for people who are allergic to eggs.
"People with egg allergy of any severity can receive the influenza vaccine without any special precautions," said Dr. Matthew Greenhawt, the paper's lead author and chairman of the American College of Allergy, Asthma and Immunology.
The new findings mean that even more people will be able to get their recommended flu shot without sacrificing peace of mind.
Greenhawt, who is also an associate professor of pediatrics at Children's Hospital Colorado, estimates that egg allergy affects 2% of children in the United States.
"It's very rare to see an adult with egg allergy -- not impossible," he said. "One redeeming quality about egg allergy is that the majority of it is outgrown at some point in childhood, with a very small proportion of individuals retaining that into adulthood. ... It's primarily a pediatric problem."
According to a press release accompanying the new report, it is no longer necessary to:
- See an allergy specialist for the flu shot.
- Give special flu shots that don't contain traces of egg.
- Require longer-than-normal observation periods after the shot.
- Ask about egg allergy before giving the vaccine.
The new guidelines are the result of an analysis of 28 studies involving thousands of people with egg allergy, including hundreds with severe egg allergy.
The researchers concluded that someone who is allergic to eggs is not at an increased risk of experiencing an adverse reaction to the flu vaccine.
"That doesn't rule out that somebody might react to the influenza vaccine," Greenhawt said. "Any provider who's giving vaccines needs to be prepared to recognize and manage an adverse reaction to a vaccine, including a severe reaction like anaphylaxis."
Anaphylaxis -- a potentially life-threatening allergic reaction -- "can occur rarely after the administration of any vaccine to any patient at a rate of approximately 1 per million," according to research conducted by Dr. John Kelso, an allergist and immunologist at Scripps Health, who co-authored the new guidelines.
Symptoms of the flu usually come on quickly and can include fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches and fatigue, according to the CDC.
"You may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick," the agency says. "Although people with the flu are most contagious in the first 3-4 days after their illness begins, some otherwise healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick."
The best ways to avoid the flu include staying away from people who you know or suspect may be sick; covering your mouth when you cough and nose when you sneeze; and washing your hands regularly -- especially during the cold winter months.
Even though it is the single most effective way to prevent infection, only 46.8% of people living in the United States got vaccinated for the 2016-17 flu season, according to CDC data. Experts say it's still not too late to get your 2017-18 shot.
"This is the best preventative measure we have against contracting influenza," Greenhawt said. "It's a very important vaccine to get every year."
The CDC recommends a yearly flu vaccine for everyone 6 months and older
Flu shots are safe for people with an egg allergy, according to new guidelines