It seems even influenza is kinder towards the richer among us, especially if you’re not vaccinated against it.

A recent report from the Centers for Disease Control and Prevention has found that the likelihood of a flu-related hospitalization was noticeably greater for people living in high-poverty areas when compared to residents of a low-poverty area during the flu seasons of 2011 and 2012 — nearly as twice. A similar increased risk was seen for hospitalizations needing intensive care, mechanical ventilation, and those that ultimately ended in death.

“These findings suggest that persons living in poorer census tracts should be targeted for enhanced influenza vaccination outreach and clinicians serving these persons should be made aware of current recommendations for use of antiviral agents to treat influenza,” the authors wrote.

To come up with their comparison, the CDC researchers turned to data obtained from the Influenza Hospitalization Surveillance Network (FluSurv-NET), a “national sentinel surveillance system established in 2009 that conducts population-based surveillance for laboratory-confirmed influenza-associated hospitalizations annually during October–April.” Looking at 78 FluSurv-NET sites from 14 different states, they ultimately focused on the 7,936 (out of 8,304) people who both visited the hospital because of their influenza and had confirmed residential addresses.

High poverty areas were defined as neighborhoods where 20 or more percent of the population is living below the poverty line, whereas low poverty areas have less than 5 percent living below the line. After adjusting for age and combining both flu seasons, the researchers estimated that out of 100,000 people, around 22 would experience a flu-related hospitalization in a year’s time if they lived in a high-poverty area; for low-poverty areas, that risk was cut in half. This relationship remained steady across all 14 states.

“Possible contributing factors are lower vaccination rates in residents of poorer census tracts, poverty-related crowding with higher rates of influenza transmission, and higher prevalence of medical conditions predisposing persons to influenza complications in poorer areas,” they explained. “However, differences in vaccination rates cannot fully explain all the age-specific differences by census tract poverty observed: only hospitalized influenza patients aged ≥65 years had a large enough difference in vaccination rates to fully explain the findings.” 94 percent of hospitalizations in high poverty areas occurred among the elderly, compared to 80 percent in low poverty neighborhoods.

Having reaffirmed earlier, if smaller, studies looking at the connection between poverty and influenza, the authors advocate for a broader public health approach to combatting the flu.

“Regardless of the causes, to reduce poverty-associated disparities in influenza-related hospitalizations, there is a need to increase influenza vaccination levels in higher poverty neighborhoods and to more fully implement recommendations on the use of antivirals in the outpatient setting,” they wrote. “This will require enhanced efforts by public health agencies and health care providers to address missed opportunities for vaccination and system barriers, as well as a better understanding of personal barriers to influenza vaccination in these neighborhoods. In addition, it will require evaluation of use of antivirals and efforts to improve them.”

Source: Hadler J, Yousey-Hindes K, Pérez A, et al. Influenza-Related Hospitalizations and Poverty Levels — United States, 2010–2012. MMWR. 2016.