A lot of people get sick every year due to the influenza virus. Some are hospitalized and a few even die.
It’s intersting to see how the hospitalization rates varied over years
CDC tracks this very closely as they do with several other infectious diseases.
Check out the data on hospitalization for the last 4 years. It’s very interesting to observe how the rates varied over these years for various age groups. Part of this speaks volume to the ability of the health care professionals ability to understand this dynamics and vaccinate the population (for example the age 50+ group did not get vaccination priority in until the 2nd half of the 2009-2010 flu season when they realized it was this group that’s most vulnerable.
More research is needed to prevent infection with influenza and if someone does get flu, how to mitigate the symptoms preventing hospitalization and even death. This particular research is definitely a step in that direction.
New research on mice has shown that pulmonary administration of granulocyte macrophage-colony stimulating factor (GM-CSF) significantly reduces flu symptoms and prevents death after a lethal dose influenza virus. While GM-SCF therapy for humans as a flu prophylaxis or treatment may be years away, the study results were striking: All of the mice treated with GM-SCF survived after being infected with the influenza virus, whereas untreated mice all died from the same infection.
"Such unique and unambiguous results demonstrate the great potential of GM-CSF and may be the remedy for a critical public health priority: developing strategies to reduce the morbidity and mortality from influenza," said Homayoun Shams, PhD, principal investigator of the study.
The results were posted online ahead of the print edition of the American Journal of Respiratory and Critical Care Medicine.
GM-SCF boosts innate immunity to make it immediately effective against the virus, and its protective effect has not been shown to be strain dependant so far. Alveolar macrophages (AM), which are enhanced by GM-SCF, are an essential piece of the innate immune response and are known to contribute to host defense against flu infections in animal models.
"Unlike a vaccine, GM-SCF does not rely heavily on the body’s ability to mount an immune counter-attack against a specific antigen or virus strain, but enhances the speed of local responses to virus infection and delicately balances the host immune responses," explained Dr. Shams.
Dr. Shams and colleagues wanted to test the idea that boosting AM by introducing GM-SCF would protect against flu. They used three types of mice to test their hypothesis: wild-type (WT) mice, transgenic mice that do not express any GM-SCF (GM-/-), and transgenic mice that express GM-SCF only in the lung (SPC-GM). They infected all three strains of mice with lethal doses of influenza virus. After progressive weight loss, all WT and GM-/- mice died within days. In contrast, all SPC-GM mice survived, and they gained back the weight they initially lost after a short period.
GM-SCF is already in use in humans as a therapy for neutropenia, and Dr. Shams hopes to eventually test its effectiveness in clinical trials for preventing or treating flu exposure. "If additional work determines that delivery of GM-SCF to the lungs after onset of symptoms improves the outcome of influenza infection, this strategy has great potential to represent a new intervention to reduce morbidity and mortality from influenza in humans," he said.