A joint position statement from the European Academy of Allergy and Clinical Immunology (EAACI) and Allergic Rhinitis and its Impact on Asthma (ARIA) relating to the use of allergen-specific immunotherapy (AIT) has been recently published.
The position statement is designed to support allergists and any physicians performing AIT in their daily practice and provides clear recommendations for the use of these treatment in patients during the COVID-19 pandemic as discussed below.
AIT describes a disease-modifying therapy that provides a long-term clinical benefit in patients with immunoglobin E (IgE)-mediated, immediate-type allergic airways diseases such as allergic bronchial asthma and allergic rhinoconjuctivitis. The objective of AIT is to decrease the symptoms experienced by a patient when exposed to a specific allergen and treatment typically involves gradual administration of increasing amounts of a specific allergen until a dose is reached at which immune tolerance is achieved. AIT can also be used to reduce the risk of developing asthma in patients with allergic rhinitis and has been shown to be effective against IgE-mediated food allergies.
AIT and viral infections
The joint position paper makes clear how the presence of allergic airway diseases are associated with an increased risk of infections but recognises that there is limited evidence of the impact of viral infections on allergic diseases. Some evidence cited from studies of patients using AIT with influenza have demonstrated that there was no difference in symptoms in those with or without allergic asthma. Other work in patients with HIV has also shown that AIT treatment is both effective, safe and well-tolerated.
In an overview of the mode of action of AIT, the joint position statement discusses how allergen-specific immune tolerance is developed through several different mechanisms directed at T and B cells, leading to a suppression of their cytokines though this mechanism does not affect the whole immune system. Consequently, patients using AIT are not likely to be become immunocompromised. The position paper however, does cite recent data that indicates how infection with COVID-19 leads to lymphopaenia and, in particular, a reduction in both CD4, CD8 and natural killer lymphocytes which affect a patient’s ability to mount an anti-viral response. While AIT reduces allergen-specific Th2 cells, according to the available data, it appears that COVID-19 infection is linked to a systemic Th1 response and subsequent cytokine storm. These observations therefore suggest that AIT is unlikely to interfere with viral infections.
Allergy services and control measures
The position paper advises that allergy departments follow infection prevention and control measures introduced by the World Health Organization and the European Centre for Disease Prevention and Control, for all patients undergoing AIT as these measures cover the reporting and transfer of patients with possible or confirmed COVID-19 infection.
In an effort to reduce the number of patients who may be infected coming into contact with allergy staff, it is suggested that those who feel ill with typical respiratory symptoms (for example, cough, fever) should contact their allergy department by telephone or via e-Health/telemedicine to seek medical advice and triage before attending their appointment.
A further recommendation is that all allergy service staff including doctors, nurses and administrative staff should:
- Be fully aware of the COVID-19 situation in their country and relevant risk factors for infection
- Know the clinical signs and symptoms of COVID-19 infection
- Follow appropriate infection and control procedures.
The position paper advises that departments have access to appropriate personal protective equipment (PPE) to ensure standard, contact and droplet protection. It is also recommended that each allergy department appoints a dedicated member of staff who is able to take the lead on COVID-19 preparedness and to implement the relevant infrastructure and control measure policies.
A useful and practical suggestion in the position paper is for departments to create notices that are displayed on all entrance doors, listing the main COVID-19 symptoms. This is designed to ensure that visitors are aware of COVID-19 symptoms and informed that they should not enter the department if they have any of these recognised symptoms, for example, fever, cough. In addition, everyone entering the department should adopt hand hygiene measures such as using soap and water or an alcohol-based hand rub.
The position paper advocates the use of a case-by-case approach for a risk assessment of whether individual staff undertaking AIT should use PPE. Nevertheless, in light of the potential for airborne transmission of COVID-19, it is strongly advised that appropriate PPE is used, especially for aerosol-generating procedures such as swabbing. Another practice piece of advice that staff provide surgical masks for patients with respiratory symptoms.
AIT treatments
AIT is available in several different formulations, for example, subcutaneous and sublingual and would normally require recurrent contact with a physician or nurse over extended periods time (which can be up to three years) before immune tolerance is developed. This necessitates many patient appointments, especially among those receiving subcutaneous injections that are administered daily or weekly (during the up dosing phase) and monthly during the continuation phase. In contrast, sublingual therapy although initiated at the allergy clinic can be continued by patients themselves at home thus avoiding the need to visit the department.
AIT use during viral respiratory infections
The position paper notes the recommendation to temporarily suspend both subcutaneous and sublingual therapies in patients who experience an acute respiratory tract infection until the infection has resolved and this recommendation is extended to those with COVID-19.
- Therefore subcutaneous or sublingual AIT should be STOPPED in those with diagnosed or suspected COVID-19 infection.
However, AIT can be restarted or continued for patients who have recovered from COVID-19 and who are symptom free.
Patients without COVID-19
For patients who are not known or suspected of having COVID-19 infection:
- Both subcutaneous and sublingual therapy should CONTINUE especially in life-threatening allergies such as venom allergy.
The position statement concludes by stating that their recommendations are conditional due to the lack of available data on COVID-19 and that revisions will be implemented when any new or relevant information becomes available.
Reference
Akdis C et al. Handling of allergen immunotherapy in the COVID-19 pandemic: An ARIRA-EAACI statement. Allergy 2020;Apr 24 doi: 10.1111/all.14336. [Online ahead of print].
