Subject: To NFPs and OCPs for influenza FOR INFORMATION: Surveillance and targeted testing for avian influenza in humans and other PH prevention and response measures
From: "ECDC respiratory viruses" <[email-masked]>
Cc: "ECDC Info" <[email-masked]>
Date: Thu, 30 May 2024 21:23:38 +0300

Tähelepanu! Tegemist on väljastpoolt asutust saabunud kirjaga. Tundmatu 
saatja korral palume linke ja faile mitte avada.

To:         National Focal Points for Viral Respiratory Diseases, 
Operational Contact Points for influenza

Cc:         National Coordinators

Dear colleagues,

With this email we would like to raise your attention to the ECDC and joint 
ECDC/EFSA published documents related to avian influenza prevention and 
response measures, including enhanced surveillance and targeted testing in 
humans.

Highly pathogenic avian influenza (HPAI) A(H5N1) viruses continue to be 
widespread in wild bird populations across the EU/EEA. Viruses circulating 
in wild birds can spillover to both wild and domestic animals, leading to 
outbreaks in poultry and occasional cases in mammals. ECDC publishes 
together with EFSA a quarterly avian influenza monitoring report with more 
information on the epidemiological situation and human cases globally. The 
latest report can be found here: ECDC/EFSA quarterly monitoring report.

A public update, including updates for ongoing events (including the US 
A(H5N1) cattle transmission event and associated human cases) is also 
provided regularly through the ECDC Communicable Disease Threats Report 
(CDTR). The latest CDTR can be found 
<https://www.ecdc.europa.eu/sites/default/files/documents/Communicable-disease-threats-report-week-21-2024_0.pdf> 
here.

Prevention and response measures related to infections in humans

Although human infections from currently circulating 2.3.4.4b A(H5N1) 
influenza viruses remain rare despite widespread transmission among animals, 
sporadic human cases among exposed individuals can be expected. Active 
monitoring and testing of exposed persons to infected animals is recommended 
for early detection of human cases and to assess the possibility of 
human-to-human transmission. Enhanced surveillance should be considered in 
the context of the ongoing avian influenza outbreaks in animals; more 
information on the relevant ECDC documents is given below.

Follow-up of people exposed to animals infected with avian influenza and 
targeted testing

ECDC has published an Investigation protocol for human exposures and cases 
of avian influenza in the EU/EEA that 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 of avian influenza. People exposed to infected animals 
should be followed up to identify early transmission from animals to humans, 
as well as between humans.

The protocol recommends that follow-up should last between 10 to 14 days 
after last exposure. This could involve active follow-up, where health 
authorities contact the individuals daily or frequently to check for the 
onset of symptoms, or passive follow-up, which might include daily 
self-checks and reporting of health status.

If individuals develop symptoms, which could range from fever, 
conjunctivitis, and diarrhoea to respiratory, neurological, or other 
atypical symptoms, immediate testing should be undertaken, and the 
individuals should isolate. Those who have been in close contact with 
confirmed cases should also be tested and monitored to prevent further 
spread and to track transmission. Testing of asymptomatic individuals who 
have been exposed may be conducted on a case-by-case basis, taking into 
account the level of exposure.

Given the uncertainties related to mammal-to-mammal transmission and 
according to the epidemiological situation, a low threshold for testing 
persons exposed to potentially infected mammals can be considered (for 
example symptomatic individuals with conjunctivitis or respiratory 
symptoms). Serological testing can be applied in the context of avian 
influenza outbreaks in the area and follow-up studies to evaluate the 
seroconversion upon exposure and support the overall risk assessment for 
zoonotic transmission.

More information on testing and detection of zoonotic influenza virus 
infections in humans in the EU/EEA, and occupational safety and health 
measures for those exposed at work can be found at the joint 
ECDC/EFSA/EU-OSHA/EURL operational guidance ‘Testing and detection of 
zoonotic influenza virus infections in humans in the EU/EEA, and 
occupational safety and health measures for those exposed at work’.

Enhanced avian influenza surveillance to identify human infections

ECDC published jointly with 
<https://www.ecdc.europa.eu/en/publications-data/operational-considerations-respiratory-virus-surveillance-europe> 
WHO Euro operational considerations for respiratory virus surveillance in 
Europe that describe how to strengthen and design surveillance systems for 
respiratory viruses to fulfil different surveillance objectives. 
Particularly, sentinel surveillance systems in primary and secondary care 
are considered important for the monitoring of respiratory viruses in the 
EU/EEA, but these systems are not designed and powered to early identify a 
newly emerging virus such as avian influenza in the general population and 
to implement control measures. Ideally all influenza positive specimens from 
sentinel sources should be typed and subtyped. Surveillance of influenza and 
other respiratory viruses should be expanded throughout the whole year.

ECDC has published surveillance guidance documents with considerations 
regarding the monitoring of avian influenza during both the influenza season 
and the inter-seasonal periods: ‘Targeted surveillance to identify human 
infections with avian influenza virus during the influenza season 2023/24, 
EU/EEA’ and ‘Enhanced surveillance of severe avian influenza virus 
infections in hospital settings in the EU/EEA’ respectively. Below we 
provide a summary of aspects that are considered in these documents. During 
the influenza season, a risk-based approach has been suggested based on the 
knowledge of avian influenza outbreaks in specific geographical areas; 
testing and sub-typing approaches for avian influenza virus need to be 
proportionate to the epidemiological situation and the capacities of 
reference laboratories.

During periods of very low seasonal influenza circulation, enhanced 
surveillance for hospitalised cases should be considered in all geographic 
locations irrespective of the presence of know avian influenza outbreaks.

Specifically:

*	Clinicians should collect the history of exposure to sick or dead animals 
of patients hospitalised with respiratory symptoms. This exposure risk 
assessment should inform the decision to test for avian influenza A(H5).
*	Specimens from hospitalised patients with very severe influenza A virus 
infection should be considered for further subtyping. During the summer 
period that we are soon entering, subtyping all hospitalised cases of 
influenza A can be considered to detect unexpected cases of avian influenza.
*	Hospitalised patients with unexplained viral encephalitis or 
meningoencephalitis should be tested for seasonal influenza virus. If the 
influenza A virus is detected, further subtyping should be performed to 
exclude avian influenza.
*	In addition, clusters of severe respiratory infections requiring 
hospitalization should be investigated. If routine testing for respiratory 
pathogens yields inconclusive results, tests for avian influenza should be 
carried out.
*	In general, any laboratory-confirmed influenza A positive sample that does 
not subtype as seasonal influenza virus (i.e., gives a negative result for 
both H3 and H1pdm09) from sentinel or non-sentinel primary or secondary-care 
sources should be tested specifically for the avian influenza H5 subtype.
*	Positive samples for A(H5) should be sent to the national influenza 
reference laboratories for further confirmation.
*	All A(H5) positive samples should be sequenced.
*	Positive samples should be sent to the 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).

Finally, wastewater surveillance could be considered as an additional 
monitoring system locally, although so far there is very limited experience 
in using this method to identify low-level circulation of zoonotic influenza 
virus infections in the human population.

Other options for preventive measures

Options for One Health mitigation measures in the human and animal sectors 
to reduce the potential of transmission to humans as well as the drivers and 
critical steps for a pandemic due to avian influenza are discussed in the 
joint ECDC/EFSA technical report ‘Drivers for a pandemic 
<https://www.ecdc.europa.eu/en/publications-data/drivers-pandemic-due-avian-influenza-and-options-one-health-mitigation-measures> 
due to avian influenza and options for One Health mitigation measures’. In 
order to protect human health, a strong collaboration between the animal and 
human sectors is critical.

Diagnostic accessibility: Access to diagnostic processes, including genomic 
technologies should be ensured.

Minimizing exposure: Appropriate personal protective equipment according to 
the level and type of exposure together with stringent hygiene, biosafety, 
and biosecurity measures to minimize exposure can be employed. Due to the 
higher risk of infection for individuals exposed to infected animals and 
contaminated environments, appropriate personal protective equipment and 
other precautionary measures should always be taken to reduce the risk of 
infection.

Public communication: The risks of exposure and human infection by avian 
influenza to the public and how it can be mitigated should be communicated 
and awareness-raising programs should be targeted for multiple audiences, 
under a One Health plan, as discussed in the ECDC document ‘Investigation 
protocol for human exposures and cases of avian influenza in the EU/EEA’. 
Guidance tailored to specific occupational groups, or people engaged in 
recreational activities where additional measures may be beneficial, should 
be provided.

Antiviral treatment: Antiviral drug treatment can be administered to humans 
infected with avian influenza as soon as symptoms appear; post-exposure 
prophylaxis can also be considered.

Seasonal influenza vaccination: Vaccination against seasonal influenza to 
minimize the risk of virus reassortment between avian and human influenza 
strains can be considered, adhering to the vaccination recommendations by 
national authorities. Vaccination should be complemented with other 
preventive measures as appropriate.

Avian influenza A(H5) vaccination: Immunization against influenza A(H5) for 
individuals occupationally exposed could be considered. Specific vaccination 
recommendations are under the remit of national authorities.

More information on the preparedness measures that countries have 
implemented and laboratory capacities and capabilities to detect and 
characterise zoonotic influenza viruses can be found in the two ECDC survey 
reports here: 
<https://www.ecdc.europa.eu/en/publications-data/avian-influenza-survey-report-laboratory-capacity> 
Survey report on laboratory capacity for molecular diagnosis and 
characterisation of zoonotic influenza viruses in human specimens in EU/EEA 
and the Western Balkans and EU/EEA country survey on measures applied to 
protect exposed people during outbreaks of highly pathogenic avian influenza 
<https://www.ecdc.europa.eu/en/publications-data/avian-influenza-survey-measures-applied> 
. An updated survey focused mainly on surveillance and targeted testing is 
currently ongoing.

If you need more information or support, please contact 
[email-masked] <mailto:[email-masked]>

Best regards,

The ECDC Respiratory Viruses and Legionella group

European Centre for Disease Prevention and Control (ECDC)Gustav III:s boulevard 40, 169 73 Solna, Sweden

Phone +46 (0)8 58 60 10 00

 <https://www.ecdc.europa.eu/> www.ecdc.europa.eu

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