The number of flu cases is on the decline after peaking in late October, but health experts are warning people not to let down their guard on the pandemic H1N1 virus.
Dr. Edward Oldfield, an expert on infectious diseases and professor of immunology at Eastern Virginia Medical School, agreed to answer questions about the current swine flu situation. Oldfield also serves as an infectious disease doctor at Sentara Norfolk General Hospital.
Q. How has this pandemic flu compared with past strains?
A. It looks like this particular pandemic strain is quite infectious, but the overall severity may prove less than the seasonal flu. We rate the flu pandemics 1 through 5, like hurricanes. If anything, this is a category 1 or less, the equivalent of a tropical storm. As anyone in Tidewater knows, a tropical storm can cause significant problems. But the overall mortality is less than the seasonal flu.
Q. What are you seeing at hospitals?
A. The pediatric hospital has had much more activity than the adult hospitals. We have seen the numbers decline at Norfolk General and across Sentara hospitals during the past two weeks. We are hoping we are over the peak. But don't let your guard down. Get the vaccine.
A lot of people see that the activity is going down and they think, "I don't need the vaccine." I think that's not true. I think you will see recurring waves of this virus. I think by the end of November we will have seen a significant decrease in the pandemic strain, but we may see future waves even this season.
Q. How soon would you expect to see another wave of the pandemic H1N1?
A. It's unpredictable. Many people feel it could come back in the January-February time frame with the seasonal flu.
Q. What is that likely to look like?
A. It could get very confusing. Tamiflu is the major defense against this particular pandemic H1N1 flu. But one of the seasonal flu strains is completely resistant to Tamiflu.
When the two are circulating together, you may have a situation where treatment decisions will get confusing.... Some people have asked, "Why are we only using Tamiflu on high-risk populations?"
If we overuse Tamiflu, we may lose it just like we have lost it to one of the seasonal flu viruses.
Q. How long has one of the seasonal flu strains been resistant to Tamiflu?
A. The last couple of seasons. It took a while to develop resistance, but once it started, people were surprised how quickly it lost effectiveness. There are three seasonal virus strains; one is resistant to Tamiflu, but the other two are still sensitive.
Q. We've had four confirmed deaths from the pandemic H1N1 virus in this region. How, exactly, does the flu kill people?
A. There are three ways any influenza can cause significant illness.
One is the virus can directly affect cells in the lungs to produce pneumonia, which can cause death.
Another way is your body produces something called cytokines - these are your body's natural defenses. Sometimes your body goes overboard and causes an excess of that, a cytokine storm. It's like your own defenses go haywire. Those are the people who get very sick, very quickly. The lungs fill with fluid and are damaged.
The third way is you can get a secondary bacterial infection that damages the lungs. It looks like about 20 to 30 percent of the serious cases have had a secondary infection.
Q. How has this strain been different in terms of whom it affects?
A. People born before 1957 seem to be less affected. We are not seeing people who are 60, 65 and older. But if they do get it, it can be very serious.
Q. What are some of the lessons learned from this pandemic?
A. This gave us a chance to test our pandemic plans. We were able to test surge capabilities in our hospitals, and that was extremely valuable.
We still have lessons to learn as we have learned from past pandemics.
The 1918 pandemic became one of the seasonal flu viruses. It kept coming back until it disappeared in 1957 because of the appearance of a new pandemic strain. So our seasonal flu strain may get replaced with the pandemic. We can't tell yet.
With the pandemic 1918 flu, the virus in the spring was not aggressive, but when it returned in the fall it was more aggressive.
That's another concern: This virus could still mutate to become more aggressive.
Dr. Edward Oldfield, an expert on infectious diseases and professor of immunology at Eastern Virginia Medical School, agreed to answer questions about the current swine flu situation. Oldfield also serves as an infectious disease doctor at Sentara Norfolk General Hospital.
Q. How has this pandemic flu compared with past strains?
A. It looks like this particular pandemic strain is quite infectious, but the overall severity may prove less than the seasonal flu. We rate the flu pandemics 1 through 5, like hurricanes. If anything, this is a category 1 or less, the equivalent of a tropical storm. As anyone in Tidewater knows, a tropical storm can cause significant problems. But the overall mortality is less than the seasonal flu.
Q. What are you seeing at hospitals?
A. The pediatric hospital has had much more activity than the adult hospitals. We have seen the numbers decline at Norfolk General and across Sentara hospitals during the past two weeks. We are hoping we are over the peak. But don't let your guard down. Get the vaccine.
A lot of people see that the activity is going down and they think, "I don't need the vaccine." I think that's not true. I think you will see recurring waves of this virus. I think by the end of November we will have seen a significant decrease in the pandemic strain, but we may see future waves even this season.
Q. How soon would you expect to see another wave of the pandemic H1N1?
A. It's unpredictable. Many people feel it could come back in the January-February time frame with the seasonal flu.
Q. What is that likely to look like?
A. It could get very confusing. Tamiflu is the major defense against this particular pandemic H1N1 flu. But one of the seasonal flu strains is completely resistant to Tamiflu.
When the two are circulating together, you may have a situation where treatment decisions will get confusing.... Some people have asked, "Why are we only using Tamiflu on high-risk populations?"
If we overuse Tamiflu, we may lose it just like we have lost it to one of the seasonal flu viruses.
Q. How long has one of the seasonal flu strains been resistant to Tamiflu?
A. The last couple of seasons. It took a while to develop resistance, but once it started, people were surprised how quickly it lost effectiveness. There are three seasonal virus strains; one is resistant to Tamiflu, but the other two are still sensitive.
Q. We've had four confirmed deaths from the pandemic H1N1 virus in this region. How, exactly, does the flu kill people?
A. There are three ways any influenza can cause significant illness.
One is the virus can directly affect cells in the lungs to produce pneumonia, which can cause death.
Another way is your body produces something called cytokines - these are your body's natural defenses. Sometimes your body goes overboard and causes an excess of that, a cytokine storm. It's like your own defenses go haywire. Those are the people who get very sick, very quickly. The lungs fill with fluid and are damaged.
The third way is you can get a secondary bacterial infection that damages the lungs. It looks like about 20 to 30 percent of the serious cases have had a secondary infection.
Q. How has this strain been different in terms of whom it affects?
A. People born before 1957 seem to be less affected. We are not seeing people who are 60, 65 and older. But if they do get it, it can be very serious.
Q. What are some of the lessons learned from this pandemic?
A. This gave us a chance to test our pandemic plans. We were able to test surge capabilities in our hospitals, and that was extremely valuable.
We still have lessons to learn as we have learned from past pandemics.
The 1918 pandemic became one of the seasonal flu viruses. It kept coming back until it disappeared in 1957 because of the appearance of a new pandemic strain. So our seasonal flu strain may get replaced with the pandemic. We can't tell yet.
With the pandemic 1918 flu, the virus in the spring was not aggressive, but when it returned in the fall it was more aggressive.
That's another concern: This virus could still mutate to become more aggressive.
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