Babies who develop several fevers in their first year are less likely to develop allergies later in life, U.S. researchers said on Monday.
The study lends support to the so-called hygiene hypothesis, which proposes that unless children’s immune systems fight infections early on, they can go into overdrive later and cause allergic reactions.
“The hygiene hypothesis is widely recognized but largely unproven,” Kenneth Adams, who oversees asthma research funded by the National Institute of Allergy and Infectious Diseases, said in a statement.
“The findings of this study strengthen the hypothesis and, after more research, could lead to preventative therapies for asthma and allergies.”
Writing in the Journal of Allergy and Clinical Immunology, Christine Johnson of the Henry Ford Health System in Detroit, and colleagues examined the medical records of 835 children from birth to age 1.
They found that half the children who experienced no fever during their first year had an allergic sensitivity by age 7.
Of those who had one fever, 46.7 percent were allergic or sensitive by age 7 but this figure dropped to 31 percent among children who suffered two or more fevers during infancy.
“We didn’t expect fever to relate with such a consistent effect,” Johnson said.
“If we can uncover which environmental factors affect allergic development and why, it may be possible to immunize children against these conditions,” she added.
Allergy is on the rise in the United States and other developed countries and scientists are working to find out why.
Some studies have shown that children who grow up with pets in the house are less likely to become allergic, another finding that supports the hygiene hypothesis.
