ECDC recommends 42 days of monitoring for contacts of imported Andes virus cases, with no routine testing in the absence of symptoms

The European Centre for Disease Prevention and Control (ECDC) recommends monitoring for 42 days of people who have been in contact with a probable or confirmed case of Andes virus infection, in situations involving sporadic cases imported into the EU and the European Economic Area. Authorities should actively follow up people with more intense exposure, while testing should be triggered by the appearance of symptoms. Routine testing of contacts without symptoms is not recommended.

In briefAll identified contacts of a probable or confirmed case should monitor their symptoms for 42 days from the last exposure. For more intense exposure, ECDC also recommends regular contact with the public health authority; at the lower level, self-monitoring is carried out without active follow-up.

The appearance of symptoms triggers self-isolation, notification of the authorities and testing, regardless of the level of exposure. Routine testing of people without symptoms is not recommended, and a negative result does not end self-isolation if symptoms persist.

On an airplane, the proximity of seats serves to identify contacts, without automatically meaning high exposure. Authorities should assess the actual interaction, its duration and any contact with secretions.

Human-to-human transmission remains uncommon, and the operational exposure criteria have not been formally validated for Andes virus. The recommendations retain individual assessment and the possibility of precautionary measures when information is incomplete.

The recommendations address differences between the national measures applied after an imported case reported by France at the beginning of August. The person had returned from Argentina and was subsequently cared for in Spain. Investigations by the French and Spanish authorities identified contacts among family members, healthcare personnel and travelers, but the approaches differed particularly regarding quarantine for people without symptoms. Some states questioned the proportionality of prolonged quarantine in relation to the relatively low and uncertain risk of human-to-human transmission in such cases.

ECDC organizes the response around two criteria. “The level of exposure determines the intensity of monitoring. Symptoms determine testing and clinical intervention,” the agency states. For both exposure categories, the follow-up period begins at the last contact involving risk, considered day zero. More intense exposure also entails regular contact with the public health authority, preferably by telephone; for lower exposure, self-monitoring is recommended without this active follow-up.

The more intense exposure category includes known contact with respiratory secretions, saliva, blood or other fluids of an infected person, including during caregiving, intimate contact or sharing the same bed. Close interactions that expose a person to respiratory particles are also included, as are unprotected exposures in healthcare services or laboratories. Interactions limited in duration or proximity and care provided with appropriate personal protective equipment throughout the exposure may be classified at the lower level.

In transport, the occupied seat helps locate contacts, but does not by itself establish the intensity of exposure. For flights longer than six hours, authorities may assess passengers in the same row and in the two rows in front of and behind them. Classification then depends on the actual interaction, the duration of the journey and any contact with secretions. A seat close to that of the infected person does not automatically mean high exposure.

If compatible symptoms appear, the recommendation is the same regardless of the contact's initial category: self-isolation, immediate notification of the public health authority and testing as soon as possible. Relevant symptoms include fever, muscle aches, chills, marked fatigue and digestive or respiratory manifestations. ECDC recommends RT-PCR testing, preferably from whole blood, and a positive result for acute infection requires managing the person as a confirmed case and isolating them in a medical facility, because their clinical condition may deteriorate rapidly.

A negative result does not automatically end the measures if symptoms persist. ECDC recommends continuing self-isolation until they disappear, clinical evaluation and consideration of repeat testing; worsening of the condition requires immediate retesting. After symptoms disappear, the person may return to monitoring appropriate to the initial exposure until the end of the 42 days calculated from the last contact involving risk.

The limitations of testing explain why a test does not replace symptom monitoring. In recommendations issued in May for high-risk contacts of the outbreak on the MV Hondius vessel, ECDC stated that a negative PCR result may appear too early to detect the infection, and identification of viral RNA does not automatically demonstrate the ability to transmit. At that time, testing people without symptoms could be considered if resources were available. The new recommendation concerns sporadic imported cases and does not recommend this routine testing.

Monitoring is accompanied by preventive measures. ECDC recommends that contacts practise hand hygiene, avoid sharing objects that may be contaminated with saliva and avoid intimate contact, as well as ensuring good ventilation during prolonged indoor interactions. The agency emphasizes that transmission of Andes virus between people is documented, but remains uncommon and is mainly associated with close and prolonged exposures.

Certainty regarding the recommendations remains limited. The evidence comes largely from retrospective investigations and observational studies, particularly from Argentina and Chile, while the operational criteria for proximity and duration of exposure have not been formally validated for Andes virus. The period of contagiousness and the role of people without symptoms are insufficiently known. As a precaution, authorities may extend contact identification to the 48 hours preceding the first symptom, but ECDC warns that this measure does not constitute evidence of presymptomatic transmission. Individual assessment and decisions by national authorities therefore remain part of applying the recommendations.

https://2eu.brussels/ro/news/ecdc-recomanda-42-de-zile-de-monitorizare-pentru-contactii-cazurilor-importate-de-virus-andes-fara-testare-de-rutina-in-absenta-simptomelor