Children and Obese Adults “Shed” Influenza Longer

Being significantly overweight, or obese, may play a significant role in the transmission of the seasonal flu.

Obesity has been found to alter the body's immune response and can lead to chronic inflammation, which increases with age.

A recent study’s conclusion suggests obesity extends how long the influenza A virus is shed, or transmitted, from infected adults.

Adults with obesity and 2 or more symptoms of influenza A, were found to shed the flu virus for 5.2 days, compared to 3.7 days among non-obese adults.

This means the flu virus was being spread 42 percent longer by obese adults.

And, age was found to contribute to flu shedding.

Children aged 0–4 years shed influenza virus 40 percent longer, and children aged 5–17 years shed influenza virus 30 percent longer than adults aged 18–92 years.

Given the dramatic rise in obesity over the past few decades, this increased risk for influenza infection poses a serious public health threat because nearly 500 million adults and children worldwide are classified as obese, said the World Health Organization (WHO).

Obesity was defined for this study by the Body Mass Index (BMI) standard from the WHO.

Influenza, a highly contagious respiratory tract infection, affects millions of adults and children each year.

Viral shedding serves as a measure for how long a person with flu might be infectious to others.

"This is the first real evidence that obesity might impact more than just disease severity," said senior study author Aubree Gordon, MPH, Ph.D., of the University of Michigan School of Public Health.

"It might directly impact transmission as well."

The authors say they're still studying this association.

The study, funded by the NIH, monitored 1,783 people in Nicaragua over the three flu seasons between 2015 and 2017. This work uses data from 2 studies of households in the catchment area of the Health Center Sócrates Flores Vivas (HCSFV) in District II of Managua, the capital of Nicaragua.

This new study’s conclusion is similar to previous studies:

• 2017
• 2013
• 2012