October 26th, 2011 (Reuters) - As Americans line up for flu shots, they should consider that the vaccines may be far less effective than thought, according to a new study.

Michael Osterholm, an infectious disease specialist at the University of Minnesota, and his colleagues found that the most common flu vaccine in the United States is effective for 59 percent of healthy adults, well below the 70 percent to 90 percent level previously reported.

"We're stuck with a vaccine that has been around for 60 years and not changed much," Osterholm said in recorded remarks. He stressed the need for a new generation of flu shots, particularly in the face of a future pandemic.

There is also a lack of information about how well the vaccine works in children and in adults over the age of 65, he said. These two groups are most at risk from flu-related illness or death.

U.S. health officials recommend that all Americans over six months of age get a flu shot. Nearly 131 million people, or 43 percent of the U.S. population, received the influenza vaccine last season, according to the Centers for Disease Control and Prevention (CDC).

Sanofi, GlaxoSmithKline, Novartis, the AstraZeneca unit MedImmune, and CSL make vaccines for the U.S. market.

While Osterholm does not dispute the need for the current vaccines, he said the common perception that they are "good enough" hinders the development of novel therapies.

In a study published in The Lancet Infectious Diseases journal, Osterholm and colleagues screened 5,707 vaccine studies published in the last 40 years.

They narrowed their analysis to 31 studies that tested for the presence of flu in laboratory tests rather than counting an increase in flu antibodies -- a faster method but one that researchers say tends to overestimate the vaccine's efficacy.

They also limited results to those that used randomized controlled trials or other observational methods that did not have "selection bias," which could lead to sicker people getting excluded from the study.

A meta-analysis of the 31 studies also showed that a newer type of vaccine that uses a live virus was 83 percent effective in protecting children between six months and seven years old.

However, this type of vaccine, which is made by MedImmune, is not currently recommended as the best treatment for children by the CDC group that decides immunization practices in the United States, the study's authors said.

The Lancet study was published ahead of a meeting of this group on Wednesday.

SOURCE: bit.ly/tQ4LAs The Lancet Infectious Diseases, online October 26, 2011.

Commentary: One of the concerns with this new report from Lancet is that it is a Meta-Analysis and Review of controlled trials. This is NOT a new study or a new trial of a new vaccine. This is a review of over 5,000 articles and 31 studies. The criteria used was Efficacy and effectiveness, at this time we are not certain what these terms mean. The criteria (efficay and effectiveness) were met in ages 18-65, meaning these people were able to report their symptoms and signs. The people outside this age range (childeren and eldery) did not appearantly meet the criteria (efficiency and effectiveness). Therefore the study concludes that the vaccine, esp the trivalent  vaccine is not as "effective" for children and elderly as it is for ages 18-65. With this said, the report is NOT indicating to not get the vaccine. It is simply stating that more research and product development needs to be done to make even BETTER vaccines. It is also mentioned that the MedImmune version of the Live virus vaccine is the best treatment for children. Caution should always be taken when a vaccine company is promoted or called the"best" in an unbiased review.

So, still get the flu vaccine !

Dr.Tim Norcross October 26th 2011.