As flu season approaches, many people wonder whether getting vaccinated twice in the same year might offer extra protection. With immunity known to fade and flu viruses changing fast, the question sounds reasonable. But according to public health experts, doubling up on flu shots rarely delivers added benefit for adults.Flu Shot: Why a Second Flu Shot Usually Does Not HelpThere is no known harm in receiving two flu shots in one year, but research shows it is largely unnecessary. Katrine Wallace, an epidemiologist at the University of Illinois at Chicago, explains that most adult immune systems have already been exposed to both the influenza virus and the vaccine over the years.Because of this prior exposure, studies have not found improved protection from a second flu shot, even among older adults whose immune responses may be weaker. For the majority of people, one influenza vaccination per year is sufficient to reduce the risk of severe illness and complications.The guidance is different for children. The US Centers for Disease Control and Prevention recommends that children under the age of nine who have never received a flu vaccine should get two doses during their first vaccination season to build adequate immunity.Flu Shot: Why You Still Need a Flu Shot Every Year?While a second shot in the same season does not add much value, annual vaccination remains important. Flu viruses mutate quickly, far faster than viruses like Covid. This means last year’s vaccine is less effective against the strains circulating this season.In addition, immunity from the flu shot gradually declines over time. These two factors make yearly vaccination necessary, even for people who rarely fall sick.Flu Shot: Which Flu Vaccine Should Children Get?As per CDC, there are two kinds of influenza vaccines in use. One is the injectable vaccine commonly known as the flu shot. The other is given as a nasal spray.This year, all flu vaccines approved for children are designed to protect against three strains of the virus, including two influenza A strains and one influenza B strain. During any flu season, several types of flu viruses can circulate at the same time, and in some cases, these viruses may shift or evolve as the season progresses.Flu Shot: Timing Matters More Than Taking Two ShotsExperts also stress that when you get the flu shot matters almost as much as getting it at all. Wallace notes that vaccination in August or early September is generally not advised for most adults, since protection may weaken before flu activity peaks.There are exceptions. Pregnant people in their third trimester may be advised to get vaccinated earlier to pass antibodies to their baby, who cannot receive a flu shot immediately after birth, as per the CDC.For most adults, the best approach is simple: get one flu shot per year and get it at the right time. There is no need to worry about doubling doses unless advised by a doctor. One well-timed vaccination remains the most effective and evidence-backed strategy