Rice Expert Alert: Will this year’s flu shot work?

EXPERT ALERT

David Ruth
713-348-6327
david@rice.edu

Jade Boyd
713-348-6778
jadeboyd@rice.edu

Will this year’s flu shot work?
Rice U. expert Michael Deem available to discuss flu vaccine efficacy

HOUSTON — (Oct. 2, 2018) — With annual flu shots on the horizon for millions of Americans, Rice University bioengineer and genetics expert Michael Deem is available to discuss how our immune systems target the flu, how the flu evolves to avoid detection and the challenges vaccine designers face in creating effective annual flu shots.

Michael Deem

In April, Deem and graduate student Melia Bonomo analyzed this year’s flu vaccine and predicted it will be 19 percent effective against H3N2 influenza. Flu vaccines the past two years had about 20 percent efficacy verses H3N2, the type of flu that sickened most people those years. Efficacy describes how well a vaccine protects the overall population. A 20 percent efficacy means that among those who’ve been vaccinated, 20 percent fewer will get the flu compared to those who are unvaccinated. Flu vaccine efficacy is about 60 percent in the best years and can be as low as 10 percent in bad years.

The Centers for Disease Control and Prevention still recommends getting vaccinated because all flu vaccines can prevent some infections, reduce the severity of illness and save the lives of children, the elderly and those with chronic health problems. For example, the CDC estimates that vaccination in 2016-17 — when efficacy was around 20 percent — prevented 5.3 million infections and 85,000 flu-related hospitalizations.

Deem and Bonomo’s peer-reviewed predication of 19 percent efficacy for this year’s vaccine is based on a fast, inexpensive test that compares the genetic code of the vaccine with the codes of recently circulating strains of flu that have been uploaded to global flu databases. The method, known as pEpitope (pronounced PEE-epih-tope), was invented by Deem more than 10 years ago as a fast, inexpensive way of gauging the effectiveness of proposed flu vaccines.

Annual flu vaccines are designed to protect against three types of flu — influenza B and two forms of influenza A, one H3N2 strain and one H1N1 strain. The H and N refer to hemagglutinin and neuraminidase, two proteins that cover the outside of flu particles that can cause infection when inhaled.

Deem can explain how the immune system targets flu particles for destruction based on the genetic sequences of H and N proteins, and the selective pressure that this exerts on the virus to evade detection by changing those sequences. Deem can discuss some of the consequences of this evolutionary arms race between the virus and immune system, including the tendency of the immune system to produce antibodies that correspond to a strain of the flu it has previously encountered. Because of this phenomenon, known as “original antigenic sin,” people who received flu shots in previous years but miss the shot this year may be slightly more susceptible to contracting the flu than if they’d never received a vaccination.

Vaccines are typically less effective against H3N2, the dominant type of flu in the past two seasons and the type that is predicted to be dominant this year. Deem can explain how the H3N2 efficacy of vaccines can be reduced by the egg-based production process that is used to manufacture most U.S. flu vaccines.

Deem also can explain the challenges of predicting which strain of H3N2 will become dominant and can discuss methods to better predict the emergence of new dominant strains. In 2010, for example, Deem and former student Jiankui He showed that careful analysis of the genetic code of newly emergent flu strains could be used to predict the emergence of newly dominant strains that would eventually sicken millions. Using historical sequence data, they showed they could correctly predict the emergence of dominant strains of H3N2 that were not covered by vaccines in 2002, 2003 and 2009.

Deem is Rice’s John W. Cox Professor in Biochemical and Genetic Engineering and professor of physics and astronomy. To schedule an interview with Deem, contact David Ruth at 713-348-6327 or david@rice.edu, or Jade Boyd at 713-348-6778 or jadeboyd@rice.edu.

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A high-resolution IMAGE is available for download at:
http://news.rice.edu/files/2018/09/0215_CRISPR-deem-v-lg-1926gvl.jpg
CAPTION: Michael Deem is the John W. Cox Professor in Biochemical and Genetic Engineering and professor of physics and astronomy at Rice University. (Photo by Jeff Fitlow/Rice University)

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