Stronger dose of vaccine protects elderly from flu

October 27th, 2008 - 2:38 pm ICT by IANS  

Washington, Oct 27 (IANS) Giving the elderly a dose four times the quantity of normal flu vaccines, boosts their immunity against the virus, a study has found. The higher dose of vaccine produced 30 percent to 80 percent more antibodies against flu. These findings are based on a study of nearly 4,000 people.

Ann Falsey, associate professor of medicine at the University of Rochester School of Medicine and Dentistry, conducted the research.

The immune system generally weakens as one ages, besides reducing the ability to respond to vaccination. While some studies have questioned the effectiveness of the flu vaccine in older adults, the nation’s leading public health experts stress that it’s a worthwhile, even life-saving, measure.

About 90 percent of the estimated 36,000 people who die from flu-related causes in the US each year are 65 and older, according to a Rochester School release.

“Without doubt, the influenza vaccine as it is today is beneficial for everyone, including older adults, and we strongly encourage every older person, and every person with a chronic illness, to get vaccinated,” said Falsey.

“However, older people generally don’t respond to vaccines as well as young healthy adults and, therefore, there is much room for improvement. The goal is to increase immune response in older adults, since this is one of the populations most at risk for becoming seriously ill or dying from influenza.”

The conventional flu vaccine is a combination of three circulating strains of flu, with each component consisting of 15 micrograms of material designed to evoke an immune response to protect a person against a particular type of flu.

In the study headed by Falsey and conducted at 30 sites around the country in 2006, physicians compared the immune response brought about from a traditional flu vaccine compared to that from a vaccine shot containing four times as much material - 60 micrograms of material known as hemagglutinin for each of the three components.

In the study of people in the age group of 65 and older, the larger dose was given to 2,575 participants, while 1,262 subjects received the standard dose. Scientists checked the level of antibodies in the blood of the participants one month later.

Generally, the large-dose vaccine increased the number of flu antibodies in study participants on average from about 30 to 80 percent. The level of such antibodies in the blood has long been considered a good gauge of how protected people are against the flu.

These findings were presented at the 48th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)/Infectious Diseases Society of America (IDSA) 46th annual meeting.

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