Thursday, December 14, 2023

ECDC Technical Guidance: Investigation Protocol for Human Exposures and Cases of Avian Influenza in the EU/EEA

#17,818

While human infections with HPAI H5 (and other) novel flu viruses in the EU have been a rare event, today the ECDC has released a 46-page guidance document for member nations on the protocol for dealing with human exposures and/or infections, which they describe as follows:

This protocol sets out measures for the follow-up and management of individuals exposed to infected animals and human cases of avian influenza, and for the public health management of possible and confirmed human cases. It is based on what is known from the animal-to-human and (non-sustained) human-to-human transmission events observed previously. In this protocol we recommend a precautionary approach for managing potential, possible or confirmed cases and their contacts.
This guidance was published on the same day as a survey of member nations on their avian flu protocols (see EU/EEA country survey on measures applied to protect exposed people during outbreaks of highly pathogenic avian influenza) which found `divergence' in the following areas:
  • Personal protective equipment recommendations in the context of wild bird and mammal exposures
  • Definitions for levels of exposure risk, which inform decisions on active versus passive follow-up
  • Availability of data on the number of people who were exposed (aggregated by risk level) and subsequently tested
  • Recommendations for antiviral prophylaxis and seasonal influenza vaccination
  • Requirements for testing in the context of non-respiratory symptoms
  • Availability of guidelines for healthcare workers treating avian influenza patients
  • One Health communication between laboratories and primary and secondary care providers
  • Implementation of follow-up studies, such as enhanced surveillance, serosurveys and after-action reviews.
As we've discussed previously, it takes a bit of luck to identify early cases - and possible exposures - in the community, and an outbreak may not become apparent until dozens (perhaps hundreds) of people had been infected (see UK Novel Flu Surveillance: Quantifying TTD).

Due to its length, you'll want to download and peruse the entire document, as I've only reproduced the summary below. 


This protocol sets out measures for the follow-up and management of individuals exposed to infected animals and human cases of avian influenza, and for the public health management of possible and confirmed human cases. It is based on what is known from the animal-to-human and (non-sustained) human-to-human transmission events observed previously. In this protocol we recommend a precautionary approach for managing potential, possible or confirmed cases and their contacts. 
Guidance for individuals exposed to infected animals 
  • Individuals who are occupationally or otherwise exposed to birds or mammals infected with avian influenza virus (AIV) while taking appropriate preventive precautions (such as appropriately using personal protective equipment (PPE)) should monitor their symptoms for a minimum of 10 and up to 14 days after the last exposure and test if they develop symptoms. Testing of asymptomatic exposed individuals should be considered on a case-by-case basis according to the level of exposure.  
  • Given the uncertainties related to mammal-to-mammal transmission, individuals who have been exposed to infected mammals while unprotected (e.g. pets in the household) should ideally get tested as soon as possible, as a precautionary measure.
  • Antivirals should be considered as post-exposure prophylaxis for individuals exposed to infected animals. 
Management of human cases 
  •  Human avian influenza cases should self-isolate for 14 days but may cease isolation earlier if symptoms resolve and they have two consecutive negative RT-PCR tests after Days 7−8. 
  • Antivirals should be considered early for treatment of patients with confirmed AIV infection.

 Guidance for individuals exposed to human case 

  •  Contact tracing and contact management should be coordinated by public health authorities. 
  • No contact tracing activities need to be initiated for contacts of potential cases (i.e. those exposed to infected animals without protection, but with no symptoms or laboratory confirmation yet) before test results are available. 
  • Contacts of probable human avian influenza cases should be identified and actively monitored for symptoms for 10−14 days, even before the test result of the index case becomes available. If any of the contacts develop symptoms, they should self-isolate and get tested. If the index case is negative and AIV infection is ruled out, then contact tracing activities can end. 
  • Contacts of confirmed human avian influenza cases are of particular concern and any potential human-to-human transmission needs to be monitored and studied closely due to the potential increase of pandemic risk. Close contacts of confirmed human cases should be advised to remain at home for 14 days from the last known exposure (self-quarantine) and be tested as soon as possible, so that further contact tracing can commence. If the contacts develop symptoms, they should be retested and self-isolate.  
  • Antivirals should be considered as post-exposure prophylaxis for individuals exposed confirmed human cases.

 Data sharing, preventive measures and risk communication  

  • All avian influenza viruses from human cases should be sequenced and the sequences should be shared in public databases as soon as possible (e.g. Global Initiative on Sharing All Influenza Data (GISAID), European Nucleotide Archive (ENA)).  
  • Clinical specimens from human cases should be sent to the National Influenza Centre/National Reference Laboratory for Influenza in each country and to the World Health Organization (WHO) Collaborating Centre for further characterisation.  
  • Laboratory-confirmed cases need to be reported to WHO under the International Health Regulations (IHR) (2005) and according to EU regulations, they are notifiable to the Early Warning Reporting System (EWRS), Epipulse and the European Surveillance System (TESSy).  
  • Strong collaboration between animal and human sectors and involvement of authorities for occupational safety and health (in settings where workers are involved) is paramount for an effective case investigation and response to a zoonotic event such as a case of avian influenza in humans
  • Individuals who are occupationally exposed to animals infected with avian influenza can be offered vaccination against seasonal influenza to minimise the risk of reassortment between avian and human seasonal influenza strains. National Immunisation Technical Advisory Groups (NITAGs) can be consulted for specific vaccination recommendations. 
  • Other preventive measures should focus on minimising exposure, ensuring correct use of appropriate PPE and hygiene measures, reducing environmental contamination and enhancing biosafety and biosecurity measures, as necessary.  
  • Other preventive measures should focus on minimising exposure, ensuring correct use of appropriate PPE and hygiene measures, reducing environmental contamination and enhancing biosafety and biosecurity measures, as necessary.  
  • Public health authorities should communicate about the risk to the public and raise awareness of the possibility of human infection by avian influenza. In collaboration with occupational safety authorities, they should also raise awareness among employers concerning safety procedures on farms. 

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