Published: October 2009
Written by: Sam Stebbins, MD, MPH, Director, Center for Public Health Preparedness
Yes Pennsylvania, there is a pandemic
For those who were wondering if there was going to be a pandemic this fall, the answer is unequivocally “YES!” Local, state, national, and international data all paint the same picture—the novel 2009 H1N1 virus (“swine flu”) is highly contagious and pretty much impossible to stop. In Pennsylvania, the surge is here, and we are clearly in the thick of the pandemic. So far, we are very fortunate that the virus is generally very mild; but at these numbers the cases are straining health care systems, school systems, and parents’ ability to get to work.
This first graph (Figure 1) shows the number of laboratory confirmed cases per week during the past five “regular” flu seasons, the spring wave of the novel 2009 H1N1 (small purple wave) and the current wave (big purple spike that goes nearly straight up). It is important to recognize that although “7000” seems like a lot of cases in a week, this is only the number of laboratory confirmed cases—and it is for LAST week at best, since these data were released on Tuesday of this week. It doesn’t include the larger majority of cases that didn’t get tested. Such as my family—my 11 year-old had classic symptoms two weeks ago, with moderate fever (102 ish), headache, sore throat, dry cough, and extreme fatigue. He was sick for five days. My oldest son had milder symptoms that lasted three days. My daughter initially seemed to escape, but then missed an entire week of 1st grade last week with flu-like symptoms. None of them were tested, nor did they need to be. But it is clear that they very likely have participated in the pandemic. This means that the “7000” confirmed cases last week are just the tip of the iceberg, and that the number of actual new cases for that time period is greater by a factor of 50–100; in other words, between 350,000 and 700,000! This figure is supported by CDC’s recent release that estimated that the “true” number of U.S. cases in the spring wave was 1.8–5.7 million, contrasted with only 43,677 laboratory-confirmed cases. Seven hundred thousand cases in PA means that more than 5% of the population was infected in one week.
The state and local health departments are utilizing multiple surveillance methods in addition to laboratory-confirmed cases to estimate who is being affected and where they live. State data shows increases throughout the state as indicated in this graph (Figure 2). Although the Southeastern region of the state (Philadelphia and nearby counties) was hit hardest in the spring, all regions in the state have been heavily affected so far, and all regions except North Central showed more than 80% increases last week. Information on “influenza-like illness” (ILI) from sentinel sites shows that up to 15% of college students were affected in one week, although this is likely peaking, and that pediatric practices were estimating that 9% of all visits were related to patients with ILI symptoms (normal in non-flu seasons is around 2% or less).
This graph (Figure 3) shows the age breakdown of cases so far. Again, it is important to remember that this data is based on laboratory confirmed cases, which doesn’t necessarily include all ages equally, and is likely biased towards the sicker patients since they are more likely to be tested. As can also be seen, the age group distribution for the pandemic is quite distinct from the previous “regular” flu season. Key points and trends are that similar to the spring, pre-teens and teens are most likely to be infected, followed by K-5 grade children and then younger to middle-aged adults. There is some evidence that the pandemic may be peaking in the younger age groups, while at the same time increasing in older adults and seniors. This may cause more strain on the health care system, as older adults with more complex medical problems are more likely to become seriously ill and/or die. More than 400 people have been reported hospitalized due to the pandemic in this wave, and two of the deaths reported last week were in persons aged 80 or older.
Data on flu trends in Pennsylvania can be found at PA Influenza Weekly Report.
What about Vaccine?
Although the state received initial doses of vaccine several weeks ago, additional shipments have been limited. The state website (www.h1n1inpa.com) notes that: “Pennsylvania continues to place orders with the federal government for the novel H1N1 flu vaccine for more than 4,000 pre-registered and certified providers in the state. However, due to the nationwide delay in the production of the vaccine, it is arriving in the state in very limited quantities. There are currently no public vaccination sites.”
The Pennsylvania Department of Health is recommending the limited vaccine doses for the following groups that are most vulnerable to being affected by H1N1:
- Pregnant women
- Persons six months to 24 years old
- Health care providers and EMS personnel
- Parents, household members, or caregivers of children under 6 months
- Those under 65 with certain underlying medical conditions
If you or a loved one is in one of the five priority groups, please contact your health care provider or school district to find out if the H1N1 vaccine is available near you. If you are unable to find the vaccine in your area, please call the Pennsylvania Department of Health at 1-877-PA-HEALTH (1-877-724-3258).