H1N1 and Where are we Going?

Epidemiology and Impact

Updated Influenza Data for United States, Based on CDC Surveillance Data

(CDC, Influenza Division. FluView. Available at: http://www.cdc.gov/flu/weekly/ Accessed September 16, 2009.)

• The week of September 7-12, 2009 showed that outpatient visits for influenza-like illness (ILI) were increased and that 1378 of 7569 (18%) tested specimens were positive for influenza. Of 685 influenza strains that were subtyped, 679 (99.6%) were 2009 influenza A (H1N1) viruses, 4 were type B, and 2 were seasonal H1N1.
• Testing of 562 2009 H1N1 strains showed that all were related to the A/California/07/2009 reference virus used in the vaccine.
• Sensitivity tests done on 1148 2009 H1N1 isolates showed 8 (0.6%) to be resistant to oseltamivir; review of these cases showed that all 8 patients had documented prior exposure to oseltamivir.
• During the week of September 7-12, pneumonia and influenza accounted for 6% of US deaths. This is below the epidemic threshold of 6.3%.

Schools. The CDC reported that about 25,000 students were dismissed from secondary schools on September 2, 2009. (McKay B, Simpson C. Fighting flu without big gun. Wall Street Journal. September 9, 2009. Available at: http://online.wsj.com/article/SB125245538175894251.html Accessed September 16, 2009.)

Colleges. During the week of September 12-19, 2009, US colleges and universities reported 6432 cases of influenza at 253 schools enrolled in the American College Health Association. A University of Michigan study indicated a 50% reduction in cases with hand hygiene and facemasks. (Steenhuysen J. Flu on campus: What works, what doesn't. Reuters. September 18, 2009.)

USA Today reports that 73% of US colleges and universities are declaring ILIs. Highest rates are in the Southeast and Midwest. Most cases are mild, but Tom Skinner of the CDC noted that some people "may feel like a train hit them." The most common symptoms are fever to 101-102° F, headache, aches, chills, sore throat, and cough. Students are told to rest in their rooms, take fluids, and not to go out. (Weise E. Most US campuses already reporting flu-like sicknesses. USA Today. September 9, 2009. Available at: http://www.usatoday.com/news/health/2009-09-09-swine-flu-college_N.htm Accessed September 16, 2009.)

Washington State University reported the largest outbreak of ILI, with an estimated 5400-9000 cases among 18,000 students, as well as several thousand staff. The illness is reported to be mild and last 3-5 days. Approximately 2600 students have contacted the University Health Service and about 500 have seen physicians. No tests for 2009 H1N1 are being done. One reason given for the early epidemic at this university may be the early start of classes -- August 24.(Geranios NK. Swine flu hits Washington State Univ. The Associated Press, Washington Post, September 8, 2009. Available at: http://www.washingtonpost.com/wp-dyn/content/article/2009/09/08/AR2009090802899.html Accessed September 16, 2009.)

Businesses. A national survey of 1057 randomly selected businesses in 6 categories (small, medium, large; critical or noncritical) was conducted by the Department of Homeland Security and the Harvard School of Public Health The study was funded by the CDC and took place between July 16 and August 12, 2009. Key findings from the survey of businesses (Harvard Opinion Research Program, Harvard School of Public Health. Business Preparedness: Novel Influenza A (H1N1). July 16-August 12, 2009. Available at: http://www.hsph.harvard.edu/news/press-releases/2009-releases/businesses-problems-maintaining-operations-significant-h1n1-flu-outbreak.html Accessed September 16, 2009.):

• 74% provide paid sick leave; 34% offer leave to care for others; 21% provide sick leave to care for children;
• 67% would note operational problems if 50% of workforce was off more than 2 weeks;
• Paid sick leave is offered by 74% and 35% allow paid sick leave to care for family members;
• A doctor's note is required for sick leave by 43%, and 69% that offer sick leave require a doctor's note to return after a contagious illness (relevance is concern about physician access in a pandemic);
• Strategies to decrease person-person contact (like staggered shifts) could be implemented by 50% for 1-2 weeks.

Click here for information about business planning for influenza.

Nursing homes. No outbreaks of the 2009 H1N1 virus have been reported to the CDC. This is attributed to the advanced ages of most persons in chronic care facilities, which is a reduced risk for this virus.

Hospitals. Many anticipate a surge of H1N1 influenza cases in the coming influenza season based on the experience in the Southern hemisphere. The President's Advisors estimate that there will be a 30%-50% attack rate this winter with 1.8 million hospitalizations, which will pose extreme challenges for hospitals. A 2006 Institute of Medicine report indicated that emergency medicine nationwide was "at the breaking point" in both finances and capacity. (Committee on the Future of Emergency Care in the United States Health System, Institute of Medicine. Emergency Medical Services: At the Crossroads. Washington, DC: National Academies Press; 2007.)

An analysis by the Center for Biosecurity at the University of Pittsburgh Medical Center estimated that a severe pandemic would require 4.6-fold more ICU beds and 2-fold more hospital beds. (Bartlett JG, Borio L. Healthcare epidemiology: the current status of planning for pandemic influenza and implications for health care planning in the United States. Clin Infect Dis. 2008;46:919-925.)

These concerns are compounded by the lack of a vaccine for the 2009 H1N1 virus before mid-October and the fact that there may be only enough vaccine for 25% of the target population (assuming that a single dose is required).

Social conventions in France. French companies and schools are discouraging the common greeting of a cheek kiss or hug. Others are also discouraging the handshake and the "high five." (Schipoliansky C, Cox L. Swine flu cuts the kiss in Europe. ABC News, September 9, 2009. Available at: http://abcnews.go.com/Health/SwineFluNews/swine-flu-cuts-kiss-europe/story?id=8520227 Accessed September 16, 2009.)