H7N9 influenza: What you should know now

Dr. Michael Jhung,
medical officer for the influenza division,
Centers for Disease Control and Prevention

A new flu virus has recently emerged in China, putting health officials around the world, including those at the U.S. Centers for Disease Control and Prevention, on alert. Today’s guest blog post by Dr. Michael Jhung, medical officer for the influenza division, Centers for Disease Control and Prevention, provides a status report of flu activity as of April 18, 2013, and tells you what you need to know about this novel virus that to date has led to 87 confirmed illnesses and 17 deaths.

Not long after a newsworthy 2012-2013 influenza season, flu is in the headlines again. On April 1, the World Health Organization first reported three human infections with a new influenza A (H7N9) virus in China. Since then, additional cases have been reported. Most of the people reportedly infected have had severe respiratory illness and, in some cases, have died.

Fortunately, there are currently no reported cases of H7N9 in the U.S. or anywhere outside of China. At the Centers for Disease Control and Prevention, we are following this situation closely, coordinating with domestic and international partners, taking routine preparedness steps and sharing frequent updates.

Here are some things you should know about the current H7N9 situation:

1. It is still early in the response and there is a tremendous amount that we don’t know. Our information is likely to be updated and change frequently as we learn more about H7N9. To stay informed, please visit our H7N9 page.
2. There are no confirmed cases of human infection in the U.S., and there is currently no evidence that the virus can spread in a sustained way from person-to-person. Other than advice for travelers or people who are ill, CDC is not making any additional or special recommendations for U.S. public action specific to H7N9. Travelers should continue to visit CDC’s Travelers' Health page on H7N9 for CDC’s current travel recommendations.
3. After the first human infections with H7N9 were detected in China, Chinese authorities detected H7N9 viruses in poultry in the same area where human infections have occurred. China is investigating cases, their exposures and their contacts closely. Many of the humans infected with H7N9 are reported to have had contact with poultry. The current working assumption is that most human infections with H7N9 have resulted from exposure to infected birds or contaminated environments. The extent of the outbreak in poultry is still being assessed, but China has reportedly begun removing birds from live markets. Shanghai is currently taking extra precautions by closing down its live poultry markets for the time being.
4. On Thursday, April 11, CDC received the first H7N9 virus isolate from China. Since this H7N9 virus is new and has pandemic potential, we are using the virus isolate from China to develop a candidate vaccine virus that could be used to make a vaccine if one is needed.
5. CDC also is using the virus isolate from China to:
• Develop a test kit for detecting H7N9 infections in humans.
• Test for the presence of antibodies against the H7N9 virus in human blood samples. This will allow CDC to see if some people already have immunity against this virus.
• Test to see whether existing antiviral drugs —i.e., Tamiflu and Relenza — will work to treat people who become ill from H7N9.
6. The investigation in China has not revealed any sustained — or ongoing — human-to-human spread of this virus, but non-sustained human-to-human spread of bird flu viruses has occurred in the past, most notably with H5N1. It’s likely that some limited human-to-human spread of H7N9 will occur. Sustained, community transmission is needed for a pandemic to start.

Visit cdc.gov for more information on human-to-human transmission. 


About the author:
Michael Jhung, MD, MPH, MS, is a medical officer for the Surveillance and Outbreak Response Team in the Influenza Division, National Center for Immunization and Respiratory Diseases, at the Centers for Disease Control and Prevention in Atlanta, Georgia. Dr. Jhung received his Bachelor of Science in Kinesiology from University of Michigan in 1989 and his Master of Science in Bioengineering from the University’s College of Engineering in 1994. He completed his doctorate of medicine from Case Western Reserve University School of Medicine in 2002, and his Master of Public Health in Epidemiology from University of Michigan’s School of Public Health in 2004.

Dr. Jhung began working with CDC’s Division for Healthcare Quality Promotion in 2005 as an Epidemic Intelligence Officer, where he conducted surveillance for healthcare-associated adverse events and rapidly responded to requests for assistance with investigation of health-care associated infections. Dr. Jhung graduated from the EIS program and joined Influenza Division’s Surveillance and Outbreak Response Team in 2009, where he has applied his expertise to responding to influenza outbreaks, providing scientific training of Fellows and staff, and contributing key findings to CDC’s pandemic preparedness plans.