A flu shot specially made for seniors combines high doses of immune stimulating antigens, targeted at three flu strains.
The shot, available for those over 65, was formulated with seniors in mind. According to the Mayo Clinic, older people produce 50 to 75 percent fewer antibodies than younger adults.
In one study, seniors who took the high-dose flu vaccine had 25 percent fewer cases of influenza than those who took the standard dose.
However, three clinical studies have also found that high-dose vaccine recipients were more likely to develop fever and soreness at the injection site a week after vaccination.
More than 90 percent of deaths from flu happen to people over the age of 65.