Report: Why we need a better flu vaccine

Science lacking on many current recs

Bring science back into the discussion of influenza vaccination.

That is the essential message of an extensive exploration of influenza vaccination by the Center for Infectious Disease Research & Policy (CIDRAP) at the University of Minnesota in Minneapolis. While supporting flu vaccination as providing “moderate” protection from disease, CIDRAP says U.S. public health authorities have focused too much on expanding the uptake of the existing vaccine and not enough on promoting the development of a better vaccine.

CIDRAP lobbed its biggest indictment at the Centers for Disease Control and Prevention and its Advisory Committee on Immunization Practices (ACIP) for overstating the effectiveness of the vaccine and relying on expert opinion while failing to acknowledge the weak scientific basis for many recommendations.

“There was such an emphasis placed on getting more people vaccinated that they lost sight of the [question] of ‘How well do these vaccines work?’” says Michael Osterholm, PhD, MPH, director of CIDRAP, former Minnesota state epidemiologist and lead author of the study.

CIDRAP calls on the U.S. government to declare that development of a new influenza vaccine is a “national priority” and to provide financial resources to make that a reality.

“It’s going to take at least a billion dollars, if not more, to get a new influenza vaccine that will work more effectively than the current one. There is no financial source even close to supporting the vaccine at that level,” he says.

From 2005 to 2011, the United States spent about $2 billion to develop manufacturing capacity for the influenza vaccine – but none of it on a novel, “game-changing” version, he says.

Overstatement of the effectiveness of the current vaccine essentially creates a barrier to moving forward, he says. “We have basically frozen in time real progress toward a game-changing vaccine,” he says.

Vaccine effectiveness overstated

Here are some issues that have a questionable scientific basis, according to the CIDRAP report:

  • The expansion of flu vaccination to universal vaccination. ACIP’s recommendation for universal flu vaccination was based on consensus opinion but not data on vaccine effectiveness or benefits for various age groups, CIDRAP said. “We found that a number of the new references cited to support the revised recommendations were actually unrelated to specific aspects of the new recommendations and did not present findings from new studies,” the report said.
  • The vaccine efficacy and effectiveness, including the optimal dose. Some studies used methods that overstate the vaccine effectiveness, CIDRAP found. “Our review identified 30 instances in which the authors of the current ACIP influenza vaccine statement did not apply current standards of scientific rigor to their analysis or did not cite relevant work,” the report said.
  • The impact of health care worker vaccination on influenza transmission. CDC advisors asserted that the recommendation for HCW vaccination had the highest quality evidence (category 1A), but CIDRAP found that two of four studies cited did not provide support with statistically significant results and two provided “some support.”
  • The use of the nasal vaccine (live attenuated influenza virus or LAIV) in adults. A CIDRAP meta-analysis of randomized controlled trials found that the efficacy of the nasal vaccine was 83% for children ages 6 months to 7 years, but there was no evidence of efficacy in those 8 years to 59 years of age.

“The single most important currency that public health owns is trust,” says Osterholm. “We owe it to the public to tell them exactly what we know and what we don’t know.

“We can still make recommendations,” he says. “But do we have the data to show that it’s going to have a dramatic impact on hospitalized patients? The answer is no.”


This question of the science behind influenza vaccination is not just an intellectual discussion. Osterholm suggests changes in the approach to health care worker vaccination.

He does support and encourage vaccination; the vaccine is about 59% effective and very safe. “Influenza vaccination offers more protection than not being vaccinated,” he says.

But offering the nasal vaccine as an equivalent to the traditional vaccine isn’t warranted, based on current scientific evidence, he says. “I don’t know if you vaccinate health care workers with LAIV that you’ve accomplished anything,” he says. “That’s the kind of discussion we need to be having.”

Osterholm also finds insufficient evidence for mandating vaccination or requiring health care workers to wear masks if they aren’t vaccinated. “I think that is just not in keeping with good public health,” he says of the mask policies. “If they really wanted to have the most impact right now, not just on influenza but respiratory illnesses in general, they should mandate that workers who have signs and symptoms of any respiratory illness not come to work.”

Ultimately, Osterholm says a greater awareness of the limitations of the current influenza could lead to a greater demand for a better one. A severe, global influenza pandemic remains a threat. As the CIDRAP report says, “A universal vaccine should be the goal, with a novel-antigen game-changing vaccine the minimum requirement.”

[Editor’s note: The CIDRAP report, “The Compelling Need for Game-Changing Influenza Vaccines: An Analysis of the Influenza Vaccine Enterprise and Recommendations for the Future,” is available at]