Sunday Conversation: The strategy against swine flu

By TODD ACKERMAN
Copyright 2009 Houston Chronicle
May 23, 2009, 7:01PM

Dr. Wendy Keitel, a Baylor College of Medicine professor of molecular virology and microbiology, last week began collecting blood samples from local swine flu patients that will be used in the development of a vaccine in anticipation of the virus returning this fall. Keitel, the lead investigator of the national effort, talked with Chronicle reporter Todd Ackerman about the new virus, the seasonal flu and the lure of a so-called universal flu vaccine that would work against all types of flu.

Q: What role will the blood samples play in developing a vaccine?

A: We are not making a vaccine at Baylor. What these samples will do is enable us to understand how the body develops an immunity against the illness. The changes from when sufferers are acutely ill to when they are getting better can help us figure out how a vaccine should perform. That’s important in vaccine trials.

Q: What’s the likelihood we’ll have an effective swine flu vaccine in ample supply this fall?

A: Good. Most seasonal influenza vaccine production will be done by the end of July so manufacturers will be able to switch their manufacturing capacity to swine flu at that time if it appears the virus will circulate again when influenza season starts.

Q: What are the chances the virus could mutate significantly from what we’re seeing now?

A: The most important thing people need to understand about the influenza virus is that it’s a wily and unpredictable foe. We already know that an H1N1 virus went from mild to severe in the 1918 pandemic. That doesn’t mean that this one will. I think you hope for the best and you anticipate there could be a change in the virulence. But even if doesn’t change to become more virulent, it’ll likely still cause widespread infections, deaths, doctors visits, hospitalizations and secondary pneumonias — what we see every year with seasonal influenza.

Q: To experts in the field, does it seem unacceptable that 36,000 people a year die from the flu?

A: Certainly, it’s not acceptable to us. Over 90 percent of people who die from seasonal flu are elderly, whose immune systems aren’t as strong and tend to have underlying chronic conditions that can increase their risk for complications of influenza. So there has been a tremendous effort to develop specific vaccines for the protection of the elderly and other people with underlying conditions.

Q: Is it true we still don’t know that much about the flu?

A: We know a lot about the flu, but we still have a lot to learn. Over the past 10 years, the medical community’s growing awareness of the huge impact flu has on individuals and in populations has led to a progressive expansion of immunization efforts against influenza. There’s even a move toward a universal immunization against influenza, vaccines that may stimulate immunity that lasts longer than a year. But those are hopes and dreams still.

Q: What are common misconceptions about flu viruses, generally?

A: The most common misconception is that it’s not a big deal, it’s just the flu. It’s that perception that for many years undermined efforts to control it.

Q: There seems to be a growing consensus now that adults do have some natural protection against swine flu, is that right? At what age does that start?

A: When they’ve tested blood from older people, they tend to have detectable levels of antibodies to this virus, whereas younger people don’t. We think it may be related to an H1N1 virus that circulated before 1957 and then disappeared. People born before then may have been exposed to closely related viruses and have some immunity.

Q: Why do you think swine flu caused so much more death in Mexico and seems relatively mild here?

A: I think we haven’t seen the end of it here yet. It’s not over until it’s over. I suspect it was more widespread in Mexico than reported, which would mean the death rate wasn’t as high as it seemed. That’ll be the subject of investigation. But it’s premature to draw any conclusions about whether it’s worse or better here yet.

Q: Has anything about this outbreak better prepared us for the next epidemic?

A: Yes. The concern about bird flu, H5N1, resulted in a concerted prevention effort that I think better prepared us for this, but this outbreak still exposed public health system gaps: We had shortages of rapid diagnostic tests for our labs; we had inadequate supplies or ability to get antivirals into areas where disease was occurring; and our surveillance system had huge weaknesses — we had a large outbreak that was already international before we even knew it was occurring.

todd.ackerman@chron.com