A new, stronger flu vaccine for seniors aged 65 and older has been licensed for use, according to recent reports.

The new vaccine contains four times the amount of antigen as a normal flu vaccine, according to an April 30 report in the journal Morbidity and Mortality Weekly. The Advisory Committee on Immunization Practices at the Centers for Disease Control and Prevention is still evaluating whether the new vaccine will be more effective, and is holding off its approval until more data can be gathered. Health experts say the vaccine could be very useful for seniors, especially those with chronic health conditions, such as diabetes or chronic obstructive pulmonary disease.

Seniors are particularly vulnerable to the seasonal flu. Each year, roughly 36,000 seniors die from influenza and influenza-related complication. During the last flu season, roughly 68% of adults over the age of 65 received a vaccine—the highest percentage for any age group, according to CDC data.