Influenza

November 10, 2012

As of the most recent report from the CDC (for the week ending on 11/3) shows very slight flu activity, with no states showing “widespread” activity, and  only one state (Maine) showing “regional” activity.  This is up very slightly from the prior report, but as yet there is no clear sign of epidemic activity.

A New York Times article, on November 5th, referenced a report from The Center for Infectious Disease Research and Policy, of the University of Minnesota, that reviewed the effectiveness of influenza vaccine and discussed various policy issues.

The report is rather long and technical, but a summary can be found beginning on page 120.

An important focus of the report is to understand the need for, and the obstacles to developing a better vaccine.

From the article:

Last month,, in a step tantamount to heresy in the public health world, scientists at the Center for Infectious Disease Research and Policy at the University of Minnesota released a report saying that influenza vaccinations provide only modest protection for healthy young and middle-age adults, and little if any protection for those 65 and older, who are most likely to succumb to the illness or its complications. Moreover, the report’s authors concluded, federal vaccination recommendations, which have expanded in recent years, are based on inadequate evidence and poorly executed studies.

“We have overpromoted and overhyped this vaccine,” said Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy, as well as its Center of Excellence for Influenza Research and Surveillance. “It does not protect as promoted. It’s all a sales job: it’s all public relations.”

But the article also states:

C.D.C. officials acknowledge that the vaccines do not work as well in the elderly population as they do in younger healthy adults. But, they say, the effectiveness of the flu shots, which are reformulated every year in an attempt to match the strains most likely to be circulating that season, varies depending on the population being inoculated and the year.

“Does it work as well as the measles vaccine? No, and it’s not likely to. But the vaccine works,” Dr. Joseph Bresee, chief of epidemiology and prevention in the C.D.C.’s influenza division, said. And research is advancing to improve the effectiveness of the vaccine.

Although the vaccine may be less effective at preventing influenza in the elderly, Dr. Bresee said, that is the population most susceptible to the disease and at highest risk. Anywhere from as few as 3,000 to as many as 49,000 Americans die of influenza each year, some 90 percent of them elderly.

The NY Times article(which non-subscribers may not be able to access) also highlights other assessments of flu vaccine and related policy issues.  For example:

Another Cochrane review found no evidence that vaccinating health care workers who work with the elderly has any effect on influenza or pneumonia deaths.

“Not having evidence doesn’t prove it doesn’t work; we just don’t know,” said Dr. Roger Thomas, a Cochrane Collaboration coordinator for the University of Calgary in Alberta, who was an author of both of the reviews. “The intelligent decision would be to have large, publicly funded independent trials.”

So, as usual, the flu vaccines issues are complex.  Even for those who are vaccinated, I continue to stress the value of prudence during an epidemic, adequate hygiene, maintenance of good vitamin D status, and general good nutrition as being of proven value in flu prevention.