Washington, November 20:According to a new study, seasonal flu immunization not only lowers the risk of contracting the new pandemic H1N1 strain but also reduces the need for hospitalization if you do get it.
A study of the U.S. military personnel found that the 2008-2009 seasonal flu vaccine had the ability to shield the youngest and the oldest age group. However, it failed to protect everyone from the lethal virus.
The researchers analyzed the data from the health files of 1,205 people who had contracted swine flu along with 4,820 controls who had not been infected by the virus in the military community between April and Oct. 15th of this year.
Observations by researchers
On the whole the researchers found that a shot of the seasonal flu lowered the risk of getting swine flu by 42percent while it cut the risk of being hospitalized by 62 percent.
The vaccine did not offer any defense to the personnel in the age bracket of 25 to 39. However, it was 50percent effective for those under 25 years and had a 55 percent success rate for those over 39 years.
Jose Luis Sanchez, MD, MPH, influenza team leader at the Armed Forces Health Surveillance Center in Silver Spring, Md. Stated, "This strongly suggests that prior vaccination with seasonal influenza vaccine confers some degree of cross-immunity against H1N1 swine flu.
"It's probably not conferring protection against H1N1 infections, but probably is protecting against disease and hospitalization once you are infected."
Reasons for protection unknown
Sanchez declared, "Why it protected against more severe hospitalized type outcomes — in what way or shape — we don't' know.”
The researchers had hoped that the seasonal flu vaccination would provide some protection against the pandemic but study from the Center for Disease Control and Prevention (CDC) reveals that the two viruses are too different for the antibodies raised against one, to affect the other.
People who got the seasonal flu vaccine do not have antibodies in their blood that neutralize the H1N1 swine flu.
Implications of the study
Dr Thomas Wellems president of the American Society of Tropical Medicine and Hygiene (ASTMH) stated, "These data highlight the need for concise, timely assessments of influenza vaccine effectiveness against the new A/H1N1 as well as seasonal strains.
“Although the United States military constitutes a highly immunized population that may not be generalizable to civilians, it offers unique cohorts of at-risk individuals that can be studied in randomized clinical trials. We look forward to further data from this population."
The study was presented at the 58th annual meeting of the American Society of Tropical Medicine and Hygiene, in Washington, D.C.