Friday, January 27, 2017

ECDC RRA: Human Infection With Avian Influenza A(H7N9) Virus, Fifth Update


The ECDC has published a new RRA (Rapid Risk Assessment) on the H7N9 virus currently circulating in China.  This comes after more than 200 human cases have been reported since November, a marked increase in activity compared to the past two years.    

While reports out of China remain fragmented and delayed, we've not seen any evidence that H7N9 is spreading efficiently from human to human. 

Still, concerns are elevated around the world  - as expressed earlier this week by WHO DIrector-General Chan,  and so we are seeing a lot of public health agencies releasing risk analysis statements and advice to travelers to China.

Today the ECDC released one of their patented, in-depth RRAs which serves not only as an excellent reference on the virus, but also defines the current risks to the EU.   Follow the link below to download and read the entire, data-rich document.   I've only excerpted the threat assessment for the EU

Human infection with avian influenza A(H7N9) virus, fifth update
 ECDC threat assessment for the EU

The A(H7N9) transmission pattern indicates a persistent zoonotic reservoir. The continued transmission of this reassortant avian influenza virus capable of causing severe disease in humans in one of the most densely populated areas in the world remains a cause for concern due to the potential for a pandemic virus to develop. However, the most likely current scenario for China is that these outbreaks remain local zoonotic outbreaks in which the virus is transmitted sporadically to humans in close contact with the animal reservoir, similar to the influenza A(H5N1) situation. A seasonal pattern in human infections, similar to seasonal influenza, appears to be emerging.

The epidemiology of the human cases has not changed during the most recent epidemics, however in the current wave more cases in rural areas have been detected, and cases are more widely distributed. This might be due to a change in the epidemiology of the disease in the reservoir (i.e. domestic poultry, with a higher circulation in poultry at the farm level than at live poultry markets). A higher virus circulation and prevalence in the poultry population would also contribute to increased contamination of the environment.

The recent upsurge of human cases due to a higher risk of exposure indicates the possibility of sporadic imported cases to Europe. Caution should be taken by people travelling to China to avoid direct exposure to poultry, live poultry markets or backyard farms. Travellers that have visited affected areas and develop respiratory symptoms and fever after their return should consult a physician and mention their recent travel history to initiate early diagnosis and treatment. The possibility of humans infected with A(H7N9) returning to the EU/EEA cannot be excluded. However, the risk of the disease spreading within Europe via humans is still considered low, as the virus does not transmit easily among people.

People in the EU presenting with severe respiratory or influenza-like infection and a history of travel to the affected areas in China with potential exposure to poultry or live bird markets will require careful investigation, management and infection control. Adequate samples for influenza tests should be rapidly taken and processed from patients with relevant exposure history within 10 days of symptom onset. Early or presumptive treatment with neuraminidase inhibitors should always be considered for suspect or confirmed cases, in line with relevant national and international recommendations. Contacts of confirmed cases should be followed-up, tested and offered post-exposure prophylaxis.

The risk of avian influenza viruses being transported to Europe in poultry through legal trade is negligible. EU regulations do not permit importation of live poultry, day-old chicks and hatching eggs and other birds (captive birds such as parrots, finches and ornamental birds) from China. The only poultry commodities authorised for import from China into the EU are sterilised meat products, heat-treated poultry meat from Shandong, and heat-treated egg products. Given the very heat-labile nature of all influenza viruses, these commodities are not considered to pose a risk of influenza virus transmission to consumers.

Considering the severity of the disease, the fact that limited human-to-human transmission cannot be excluded in some clusters, that no vaccine is available against A(H7N9), and the favourable safety profile of the antiviral drugs of choice, it is likely that the benefits of post-exposure chemoprophylaxis of close contacts with neuraminidase inhibitors outweigh the risks. Evidence of benefits and effectiveness of prophylaxis and treatment remain limited.

In order to decrease the risk of infection, EU citizens travelling or living in China should minimise their exposure to live poultry markets, avoid contact with live or dead poultry or their products, and practice good hand hygiene when visiting places with birds or poultry [75].

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