Image of the H7N9 virus courtesy of Cynthia S. Goldsmith and Thomas Rowe
Not long after a newsworthy 2012-2013 influenza season, flu is in the headlines again. On April 1, the World Health Organization (WHO) first reported 3 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 CDC, we are following this situation closely, coordinating with domestic and international partners, taking routine preparedness steps, and sharing frequent updates.
Here are six things you should know about the current H7N9 situation:
- 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, visit CDC’s H7N9 Virus webpage.
- There are not any 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 current travel recommendations.
- 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 human cases of 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 their live poultry markets for the time being.
- On 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.
- 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.
- The investigation in China has not revealed any sustained (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.
For more information on human-to-human transmission, visit: http://www.cdc.gov/flu/spotlights/h7n9-cases-china.htm.