IFNAR1 deficiency and vaccines
The Australian Technical Advisory Group on Immunisation (ATAGI) has prepared a statement on IFNAR1 deficiency, which does not recommend any changes to the National Immunisation Program. ATAGI recommends that all people in Australia, including people of Tongan, Samoan, and Niuean heritage, continue to receive the MMR at 12 months of age and the MMR-V vaccine at 18 months of age, given that illness from wild-type measles and mumps infections is more severe in unvaccinated individuals, including those with undiagnosed IFNAR1 deficiency. People with IFNAR1 deficiency can safely receive the rotavirus vaccine and non-live vaccinations, including the influenza and COVID-19 vaccines. Immunisation against measles is a key objective for the health and wellbeing of all Australians.
The New Zealand Ministry of Health has also developed information which is available at https://www.health.govt.nz/our-work/preventative-health-wellness/immunisation/ifnar1-deficiency-information-healthcare-professionals.
IFNAR1 deficiency is a newly described specific immune deficiency associated with severe adverse events and death following vaccination with some live attenuated virus vaccines, including the MMR vaccine, the yellow fever virus vaccine, and potentially the live varicella vaccine, though disseminated varicella post vaccination has not been seen. MMR and MMRV vaccines are available under the National Immunisation Program for all children at 12 and 18 months of age respectively.
A recent study from New Zealand and Australia described 7 cases of children who were found to have this specific immune deficiency presenting for medical attention with a hyperinflammatory symptom complex of fever, rash, shock, and hepatosplenomegaly, or symptoms of encephalopathy within 1 week of MMR vaccination. The research study can be accessed here: https://rupress.org/jem/article/219/6/e20220028/213170/A-loss-of-function-IFNAR1-allele-in-Polynesia
Although the role of MMR vaccine is not clear in all cases, 4 out of the 7 children in the study died and 3 had significant ongoing neurodevelopmental morbidity. An earlier report described complications following yellow fever virus vaccination in an adolescent with the condition. No deaths of children have been reported in Australia with IFNAR1 deficiency.
Although extremely rare, affecting less than one in one billion people, IFNAR1 deficiency appears more common in people who have two parents of Tongan, Samoan, or Niuean heritage. It is estimated to affect 1 in every 6,450 people with parents of Samoan heritage. This roughly equates to one child born every two years in Australia.
It is important for health professionals to remain aware of the advice contained in the ATAGI statement when considering administering the MMR and MMRV vaccine for patients.
This news item was issued on 6 May 2022 by Jill Smith, CEO of the Australasian Society of Clinical Immunology and Allergy (ASCIA). ASCIA is the peak professional body for clinical immunology and allergy in Australia and New Zealand.